12th Class Physics Electric Charges and Fields Question Bank

done Case Based (MCQs) - Electric Charges and Fields Total Questions - 76

• question_answer1)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): When we rub a glass rod with silk, the rod gets positively charged and the silk gets negatively charged.

  Reason (R): On rubbing, electrons from silk cloth move to the glass rod.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer2)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): Charge is quantize(d)

  Reason (R): Charge, which is less than 1 C is not possible.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false  done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer3)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): Charging is due to transfer of electrons.

  Reason (R): Mass of a body decreases slightly when it is negatively charged.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false             done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer4)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): When bodies are charged through friction, there is a transfer of electric charge from one body to another, but no creation or destruction of charge.

  Reason (R): This follows from conservation of electric charges.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false             done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer5)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): The charge on a body can be increased or decreased in terms of electronic charge e.

  Reason (R): Quantisation of charge means that the charge on a body is the integral multiple of electronic charge e.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false             done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer6)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): The coulomb force is the dominating force in the universe.

  Reason (R): The coulomb force is weaker than the gravitational force.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false             done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer7)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): Coulomb force and gravitational force follow the same inverse-square law.

  Reason (R): Both laws are same in all aspects.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false             done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer8)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): If there exists coulomb attraction between two bodies, both of them may not be charged.

  Reason (R): In coulomb attraction two bodies are oppositely charged.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false             done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer9)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): Electric force acting on a proton and an electron, moving in a uniform electric field is same, where as acceleration of electron is 1836 times that of a proton.

  Reason (R): Electron is lighter than proton.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false             done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer10)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): For charge to be in equilibrium, sum of the forces on charge due to rest of the two charges must be zero.

  Reason (R): A charge is lying at the centre of line joining two similar charges each which are fixed. The system will be in equilibrium, if that charge is one fourth of the similar charges.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer11)
            

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): The force with which two charges attract or repel each other are not affected by the presence of a third charge.

  Reason (R): Force on any charge due to a number of other charges is the vector sum of all the forces on that charge due to other charges, taken one at a time.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false   done clear
  D)
            Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer12)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): Electric field at a point superimpose to give one resultant electric field.

  Reason (R): Electric lines of force cross each other.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false             done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer13)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): Electric field is always normal to equipotential surfaces and along the direction of decreasing order of potential.

  Reason (R): Negative gradient of electric potential is electric field.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false             done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer14)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): If a proton and an electron are placed in the same uniform electric field. They experience different acceleration.

  Reason (R): Electric force on a test charge is independent of its mass.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false             done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer15)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): As force is a vector quantity, hence electric field intensity is also a vector quantity.

  Reason (R): The unit of electric field intensity is newton per coulomb.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false             done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer16)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): In a uniform electric field electron move in the opposite direction of electric field.

  Reason (R): This is because of the negative charge of an electron.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer17)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): Three equal charges are situated on a circle of radius r such that they form an equilateral triangle, then the electric field intensity at the centre is zero.

  Reason (R): The force on unit positive charge at the centre, due to the three equal charges are represented by the three sides of a triangle taken in the same order.

  Therefore, electric field intensity at centre is zero.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false             done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer18)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): No two electric lines of force can intersect each other.

  Reason (R): Tangent at any point of electric line of force gives the direction of electric field.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false             done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer19)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): Electrostatic field Lines start at positive charges and end at negative charges.

  Reason (R): Field lines are continuous curves without any breaks and they form closed loop.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false   done clear
  D)
            Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer20)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): The electric lines of forces diverges from a positive charge and converge at a negative charge.

  Reason (R): A charged particle free to move in an electric field always move along an electric Line of force.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false             done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer21)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): In electrostatics, electric lines of force can never be closed loops, as a line can never start and end on the same charge.

  Reason (R): The number of electric lines of force originating or terminating on a charge is proportional to the magnitude of charge.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false             done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer22)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): The surface charge densities of two spherical conductors of different radii are equal. Then the electric field intensities near their surface are also equal.

  Reason (R): Surface charge density is equal to charge per unit area.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false             done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer23)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): Surface charge density of an irregularly shaped conductor is non-uniform.

  Reason (R): Surface density is defined as charge per unit area.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false             done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer24)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): Total flux through a closed surface is zero, if net charge enclosed by the surface is zero.

  Reason (R): Gauss law is true for any closed surface, no matter what its shape or size is.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false             done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer25)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): The electric flux emanating out and entering a closed surface are \[8\times {{10}^{3}}\]and \[2\times {{10}^{3}}\,Vm\]respectively.

  The charge enclosed by the surface is 0.053 u(C)

  Reason (R): Gauss's theorem in electrostatics may be applied to verify.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false             done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer26)

  Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason:

  (R). Mark the correct choice as:

  Assertion (A): A point charge is lying at the centre of a cube of each side. The electric flux emanating from each surface of the cube is \[\frac{1}{6}\]th of total flux.

  Reason (R): According to Gauss theorem, total electric flux through a closed surface enclosing a charge is equal to \[{}^{1}/{}_{{{\varepsilon }_{0}}}\]times the magnitude of the charge enclosed.

  A)
  Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A) done clear
  B)
  Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A) done clear
  C)
  Assertion (A) is true but Reason (R) is false            done clear
  D)
  Assertion (A) is false and Reason (R) is also false done clear
  View Solution play_arrow

• question_answer27)

  Direction Q.1 to 5

  A charge is a property associated with the matter due to which it experiences and produces an electric and magnetic field. Charges are scalar in nature and they add up like real numbers. Also, the total charge of an isolated system is always conserved. When the objects rub against each other charges acquired by them must be equal and opposite.

  Read the above passage carefully and give the answer of the following questions.

  The cause of charging is:
  A)
  the actual transfer of protons done clear
  B)
  the actual transfer of electrons done clear
  C)
  the actual transfer of neutrons done clear
  D)
  None of the above done clear
  View Solution play_arrow

• question_answer28)
  When a glass rod is rubbed with silk:
  A)
  negative charge is produced on silk but no charge on glass rod done clear
  B)
  equal but opposite charges are produced on both done clear
  C)
  equal and similar charges are produced on both done clear
  D)
  positive charge is produced on glass rod but no charge on silk done clear
  View Solution play_arrow

• question_answer29)
  A piece of paper appears to be attracted to a charged ebonite rod, even before they touch (see fig.). The Charge at B is:
  A)
  positive done clear
  B)
  may be positive or negative done clear
  C)
  no charge done clear
  D)
  negative done clear
  View Solution play_arrow

• question_answer30)
  What happens when a charged balloon is placed near another balloon of the same charge?
  A)
  Attract each other       done clear
  B)
  Repel each other    done clear
  C)
  Neither attract nor repel done clear
  D)
  All of the above done clear
  View Solution play_arrow

• question_answer31)
  The cause of quantization of electric charges is:
  A)
  transfer of an integral number of neutrons done clear
  B)
  transfer of an integral number of protons done clear
  C)
  transfer of an integral number of electrons done clear
  D)
  None of the above done clear
  View Solution play_arrow

• question_answer32)

  Direction Q.6 to 10

  Photocopiers work on the principle that 'opposites attract'. Toner is a powder that is used to create the printed text and images on paper. The powder is negatively charged, and so it is attracted to something positive—the paper. The drum, which is located in the heart of a photocopier, is positively charged using static electricity.

  An image of the master copy is transferred onto the drum using a laser. The light parts of the image (the white areas on a piece of paper) lose their charge so becomes more negative, and the black areas of the image (where the text is) remain positively charged.

  Read the above passage carefully and give the answer of the following questions.

  Which of the following figures represent the electric field lines due to a single negative charge.
  A)
  done clear
  B)
  done clear
  C)
  done clear
  D)
  done clear
  View Solution play_arrow

• question_answer33)
  Consider a region inside which, there are various types of charges but the total charge is zero. At points outside the region:
  A)
  the electric field is necessarily zero done clear
  B)
  the electric field is due to the dipole moment of the charge distribution only done clear
  C)
  the dominant electric field is inversely proportional to \[{{r}^{3}}\]for larger r (distance from origin) done clear
  D)
  the work done to move a charged particle along a closed path, away from the region will not be zero done clear
  View Solution play_arrow

• question_answer34)
  If a body is negatively charged, then it has:
  A)
  excess of electrons done clear
  B)
      excess of protons done clear
  C)
  deficiency of electron done clear
  D)
  deficiency of neutron done clear
  View Solution play_arrow

• question_answer35)
  A charged particle is free to move in an electric field. It will travel:
  A)
  always along a line of force done clear
  B)
  along a line of force, if its initial velocity is zero done clear
  C)
  along a line of force, if it has some initial velocity in the direction of an acute angle with the line of force done clear
  D)
  None of the above done clear
  View Solution play_arrow

• question_answer36)

  Which of the following statements is incorrect?

  (i) The charge q on a body is always given by q= ne, where n is any integer, positive or negative.

  (ii) By convention, the charge on an electron is taken to be negative.

  (iii) The fact that electric charge is always an integral multiple of e is termed as quantisation of charge.

  (iv) The quantisation of charge was experimentally demonstrated by Newton in 1912.

  A)
  Only (i) done clear
  B)
  Only (ii) done clear
  C)
  Only (iv) done clear
  D)
  Only (iii) done clear
  View Solution play_arrow

• question_answer37)

  Direction Q.11 to 15

  Coulomb's law states that the electrostatic force of attraction or repulsion acting between two stationary points charges is given by

  \[F=\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{{{q}_{1}}{{q}_{2}}}{{{r}^{2}}}\]

  where F denotes the force between two charges \[{{q}_{1}}\]and \[{{q}_{2}}\] separated by a distance r in free space, e q is a constant known as permittivity of free space. Free space is vacuum and may be taken to be air practically.

  If free space is replaced by a medium, then E o is replaced by \[\left( {{\varepsilon }_{0}}k \right)\]or \[\left( {{\varepsilon }_{0}}{{\varepsilon }_{r}} \right)\]where k is known as dielectric constant or relative permittivity.

  Read the above passage carefully and give the answer of the following questions.

  In Coulomb's law, \[F=k\frac{{{q}_{1}}{{q}_{2}}}{{{r}^{2}}}\], then on which of the following factors does the proportionality constant k depends?
  A)
  Electrostatic force acting between the two charges done clear
  B)
  Nature of the medium between the two charges done clear
  C)
  Magnitude of the two charges done clear
  D)
  Distance between the two charges done clear
  View Solution play_arrow

• question_answer38)
  Dimensional formula for the permittivity constant \[{{\varepsilon }_{0}}\]of free space is:
  A)
  \[\left[ M{{L}^{-3}}{{T}^{4}}{{A}^{2}} \right]\] done clear
  B)
  \[\left[ {{M}^{-1}}{{L}^{3}}{{T}^{2}}{{A}^{2}} \right]\] done clear
  C)
  \[\left[ {{M}^{-1}}{{L}^{-3}}{{T}^{4}}{{A}^{2}} \right]\]   done clear
  D)
  \[\left[ M{{L}^{-3}}{{T}^{4}}{{A}^{-2}} \right]\] done clear
  View Solution play_arrow

• question_answer39)
  The force of repulsion between two charges of 1 C each, kept 1 m apart in vacuum is:
  A)
  \[\frac{1}{9\times {{10}^{9}}}N\]         done clear
  B)
  \[9\times {{10}^{9}}N\] done clear
  C)
  \[9\times {{10}^{7}}N\]                        done clear
  D)
  \[\frac{1}{9\times {{10}^{12}}}N\] done clear
  View Solution play_arrow

• question_answer40)
  Two identical charges repel each other with a force equal to 10 mg wt when they are 0.6m apart in air.\[\left( g=10\,m{{s}^{-2}} \right)\] The value of each charge is:
  A)
  2 mC                done clear
  B)
  \[2\times {{10}^{-7}}mC\] done clear
  C)
  \[2\,nC\]            done clear
  D)
  \[2\mu C\] done clear
  View Solution play_arrow

• question_answer41)
  Coulomb's law for the force between electric charges most closely resembles with:
  A)
  law of conservation of energy done clear
  B)
  Newton's law of gravitation done clear
  C)
  Newton's 2nd law of motion done clear
  D)
  law of conservation of charge done clear
  View Solution play_arrow

• question_answer42)

  Direction Q.16 to 20

  When a charged particle is placed in an electric field, it experiences an electrical force. If this is the only force on the particle, it must be the net force. The net force will cause the particle to accelerate according to Newton's second law. So

  If \[\overrightarrow{E}\]is uniform, then \[\overrightarrow{a}\] is constant and\[\overrightarrow{a}=q\overrightarrow{E}/m\]. If the particle has a positive charge, its acceleration is in the direction of the field. If the particle has a negative charge, its acceleration is in the direction opposite to the electric Field. Since, the acceleration is constant, the kinematic equations can be used.

  Read the above passage carefully and give the answer of the following questions.

  An electron of mass m, charge e falls through a distance h metre in a uniform electric field E. Then time of fall:
  A)
  \[t=\sqrt{\frac{2hm}{eE}}\]        done clear
  B)
  \[t=\frac{2hm}{eE}\] done clear
  C)
  \[t=\sqrt{\frac{2eE}{hm}}\]                    done clear
  D)
  \[t=\frac{2eE}{hm}\] done clear
  View Solution play_arrow

• question_answer43)
  An electron moving with a constant velocity v along X-axis enters a uniform electric field applied along Y-axis. Then the electron moves:
  A)
  with uniform acceleration along V-axis done clear
  B)
  without any acceleration along Y-axis done clear
  C)
  in a trajectory represented as \[y=a{{x}^{2}}\] done clear
  D)
  in a trajectory represented as y = ax done clear
  View Solution play_arrow

• question_answer44)
  Two equal and opposite charges of masses \[{{m}_{1}}\]and \[{{m}_{2}}\] are accelerated in an uniform electric field through the same distance. What is the ratio of their accelerations, if their ratio of masses is \[\frac{{{m}_{1}}}{{{m}_{2}}}=0.5\]?
  A)
  \[\frac{{{q}_{1}}}{{{q}_{2}}}=2\]                   done clear
  B)
  \[\frac{{{q}_{1}}}{{{q}_{2}}}=0.5\] done clear
  C)
  \[\frac{{{q}_{1}}}{{{q}_{2}}}=3\]                   done clear
  D)
  \[\frac{{{q}_{1}}}{{{q}_{2}}}=1\] done clear
  View Solution play_arrow

• question_answer45)
  A particle of mass m carrying charge q is kept at rest in a uniform electric field E and then released. The kinetic energy gained by the particle, when it moves through a distance y is:
  A)
  \[\frac{1}{2}qE{{y}^{2}}\]                  done clear
  B)
  \[qEy\] done clear
  C)
  \[qE{{y}^{2}}\]                       done clear
  D)
  \[q{{E}^{2}}y\] done clear
  View Solution play_arrow

• question_answer46)
  A charged particle is free to move in an electric field. It will travel:
  A)
  always along a line of force done clear
  B)
  along a line of force, if its initial velocity is zero done clear
  C)
  along a line of force, if it has some initial velocity in the direction of an acute angle with the line of force done clear
  D)
  None of the above           done clear
  View Solution play_arrow

• question_answer47)

  Direction Q.21 to 25

  Electric field strength is proportional to the density of lines of force i.e., electric field strength at a point is proportional to the number of lines of force cutting a unit area element placed normal to the field, at that point. As illustrated in the given figure, the electric field at P is stronger than at Q.

  Read the given passage carefully and give the answer of the following questions.

  Electric lines of force about a positive point charge are:
  A)
  radially outwards    done clear
  B)
  circular clockwise done clear
  C)
  radially inwards       done clear
  D)
  parallel straight lines          done clear
  View Solution play_arrow

• question_answer48)
  Which of the following is false for electric lines of force? :
  A)
  They always start from positive charges and terminate on negative charges done clear
  B)
  They are always perpendicular to the surface of a charged conductor done clear
  C)
  They always form closed loops done clear
  D)
  They are parallel and equally spaced in a region of uniform electric field done clear
  View Solution play_arrow

• question_answer49)
  Which one of the following pattern of electric line of force is not possible in filed due to stationary charges?
  A)
  done clear
  B)
  done clear
  C)
        done clear
  D)
  done clear
  View Solution play_arrow

• question_answer50)
  Electric lines of force are curved:  
  A)
  in the field of a single positive or negative charge done clear
  B)
  in the field of two equal and opposite charges           done clear
  C)
  in the field of two like charges   done clear
  D)
  Both (b) and (c) done clear
  View Solution play_arrow

• question_answer51)
  The figure below shows the electric field Lines due to two positive charges. The magnitudes \[{{E}_{A}},\,{{E}_{B}}\]and \[{{E}_{C}}\] of the electric fields at points A, B and C respectively are related as:
  A)
  \[{{E}_{A}}>{{E}_{B}}>{{E}_{C}}\] done clear
  B)
  \[{{E}_{B}}>{{E}_{A}}>{{E}_{C}}\] done clear
  C)
  \[{{E}_{A}}={{E}_{B}}>{{E}_{C}}\] done clear
  D)
  \[{{E}_{A}}>{{E}_{B}}={{E}_{C}}\] done clear
  View Solution play_arrow

• question_answer52)

  Direction Q.26 to 30

  When electric dipole is placed in uniform electric field, its two charges experience equal and opposites forces, which cancel each other and hence net force on electric dipole in uniform electric field is zero. However these forces are not collinear, so they give rise to some torque on the dipole. Since, net force on electric dipole in uniform electric field is zero, so no work is done in moving the electric dipole in uniform electric field. However some work is done in rotating the dipole against the torque acting on it.

  Read the given passage carefully and give the answer of the following questions.

  The dipole moment of a dipole in a uniform external field \[\overrightarrow{E}\]is \[\overrightarrow{P}\]. Then the torque \[\overrightarrow{\tau }\] acting on the dipole is:
  A)
  \[\overrightarrow{\tau }=\overrightarrow{P}\times \overrightarrow{E}\]                     done clear
  B)
  \[\overrightarrow{\tau }=\overrightarrow{P}.\overrightarrow{E}\] done clear
  C)
  \[\overrightarrow{\tau }=2\left( \overrightarrow{P}\times \overrightarrow{E} \right)\]   done clear
  D)
  \[\overrightarrow{\tau }=\left( \overrightarrow{P}+\overrightarrow{E} \right)\] done clear
  View Solution play_arrow

• question_answer53)
  An electric dipole consists of two opposite charges, each of magnitude \[1.0\,\mu C\] separated by a distance of 2.0 cm. The dipole is placed in an external field of \[{{10}^{5}}N{{C}^{-1}}\]. The maximum torque on the dipole is:
  A)
  \[0.2\times {{10}^{-3}}Nm\]     done clear
  B)
  \[1\times {{10}^{-3}}Nm\] done clear
  C)
  \[2\times {{10}^{-3}}Nm\]                    done clear
  D)
  \[4\times {{10}^{-3}}Nm\] done clear
  View Solution play_arrow

• question_answer54)
  Torque on a dipole in uniform electric field is minimum when \[\theta \]is equal to:
  A)
  \[0{}^\circ \]                 done clear
  B)
  \[90{}^\circ \] done clear
  C)
  \[180{}^\circ \]             done clear
  D)
  Both a and c done clear
  View Solution play_arrow

• question_answer55)
  When an electric dipole is held at an angle in a uniform electric field, the net force F and torque \[\tau \]on the dipole are:
  A)
  \[F=0,\,\tau =0\]                        done clear
  B)
  \[F\ne 0,\,\tau \ne 0\] done clear
  C)
  \[F=0,\,\tau \ne 0\]                     done clear
  D)
  \[F\ne 0,\,\tau =0\] done clear
  View Solution play_arrow

• question_answer56)
              An electric dipole of moment p is placed in an electric field of intensity E. The dipole acquires a position such that the axis of the dipole makes an angle \[\theta \] with the direction of the field. Assuming that the potential energy of the dipole to be zero when\[\theta =90{}^\circ \], the torque and the potential energy of the dipole will respectively be:
  A)
  \[pE\,\sin \theta ,\,-pE\,\cos \theta \] done clear
  B)
  \[pE\,\sin \theta ,\,-2pE\,\cos \theta \] done clear
  C)
  \[pE\,\sin \theta ,\,2pE\,\cos \theta \] done clear
  D)
  \[pE\,\cos \theta ,\,-pE\,\sin \theta \] done clear
  View Solution play_arrow

• question_answer57)

  Direction Q.31 to 35

  Animals emit low frequency electric fields due to process known as osmoregulation. This process allows the concentration of ions (charged atoms or molecules) to flow between the inside of our bodies and the outside. In order for our cells to stay intact, the flow of ions needs to be balanced. But balanced doesn't necessarily mean equal. The concentration of ions within a shrimp's body is much lower than that of the sea water it swims in. Their voltage, or potential difference generated between the two concentrations across 'leaky' surfaces, can then be measured.

  Read the above passage carefully and give the answer of the following questions..

  The Gaussian surface for ions in the body of animals:
  A)
  can pass through a continuous charge distribution done clear
  B)
  cannot pass through a continuous charge distribution done clear
  C)
  can pass through any system of discrete charges done clear
  D)
  can pass through a continuous charge distribution as well as any system of discrete charges done clear
  View Solution play_arrow

• question_answer58)
  Gauss's law is valid for:
  A)
  any closed surface  done clear
  B)
         only regular close surfaces                  done clear
  C)
  any open surface     done clear
  D)
               only irregular open surfaces  done clear
  View Solution play_arrow

• question_answer59)
  The electric field inside a shrimp's body of uniform charge density is:
  A)
  zero done clear
  B)
  constant different from zero done clear
  C)
  proportional to the distance from the curve             done clear
  D)
  None of the above     done clear
  View Solution play_arrow

• question_answer60)
  If a small piece of linear isotropic dielectric is swallowed by a shrimp and inside the body it is influenced by an electric field E, then the polarization P is:
  A)
  independent of E done clear
  B)
  inversely proportional to E done clear
  C)
  directly proportional to \[\sqrt{E}\] done clear
  D)
  directly proportional to E done clear
  View Solution play_arrow

• question_answer61)

  Field due to multiple charges/ions inside shrimp's body at a point is found by using:

  (i) superposition principle

  (ii) Coulomb's law

  (iii) Law of conservation of charges

  A)
  (i) and (ii) done clear
  B)
  (ii) and (iii) done clear
  C)
  (i) and (iii) done clear
  D)
  (i), (ii) and (iii) done clear
  View Solution play_arrow

• question_answer62)

  Direction Q.36 to 40

  Gauss's law and Coulomb's law, although expressed in different forms, are equivalent ways of describing the relation between charge and electric field in static conditions. Gauss's law is\[{{\varepsilon }_{0}}\phi ={{q}_{encl}}\], when \[{{q}_{encl}}\]is the net charge inside an imaginary closed surface called Gaussian surface. \[\phi =\oint{\overrightarrow{E}}\,.\,d\,\overrightarrow{A}\]gives the electric flux through the Gaussian surface. The two equations hold only when the net charge is in vacuum or air.

  Read the given passage carefully and give the answer of the following questions.

  If there is only one type of charge in the universe, then \[\left( \overrightarrow{E} \right.\to \]Electric field, \[d\,\overrightarrow{S}\to \]Area vector)                         
  A)
  \[\oint{\overrightarrow{E}}\,.\,d\,\overrightarrow{S}\ne 0\]on any surface done clear
  B)
  \[\oint{\overrightarrow{E}}\,.\,d\,\overrightarrow{S}\]could not be defined done clear
  C)
  \[\oint{\overrightarrow{E}}\,.\,d\,\overrightarrow{S}=\infty \], if charge is inside done clear
  D)
  \[\oint{\overrightarrow{E}}\,.\,d\,\overrightarrow{S}=0\], if charge is outside, \[\oint{\overrightarrow{E}}\,.\,d\,\overrightarrow{S}=\frac{q}{{{\varepsilon }_{0}}}\], if charge is inside done clear
  View Solution play_arrow

• question_answer63)
  What is the nature of Gaussian surface involved in Gauss Law of electrostatic?
  A)
  Magnetic                        done clear
  B)
  Scalar   done clear
  C)
  Vector                           done clear
  D)
  Electrical                         done clear
  View Solution play_arrow

• question_answer64)
              A charge \[10\,\mu C\] is placed at the centre of a hemisphere of       radius \[R=10\,cm\]as shown. The electric flux through the hemisphere (in MKS units) is:
  A)
  \[20\times {{10}^{5}}\]            done clear
  B)
  \[20\times {{10}^{5}}\] done clear
  C)
  \[6\times {{10}^{5}}\]              done clear
  D)
  \[2\times {{10}^{5}}\] done clear
  View Solution play_arrow

• question_answer65)
  The electric flux through a closed surface area S enclosing charge Q is \[\phi \]. If the surface area is doubled, then the flux is:
  A)
  \[2\phi \]                                    done clear
  B)
  \[\phi /2\] done clear
  C)
  \[\phi /4\]                                   done clear
  D)
  \[\phi \] done clear
  View Solution play_arrow

• question_answer66)
  A Gaussian surface encloses a dipole. The electric flux through this surface is:   
  A)
  \[\frac{q}{{{\varepsilon }_{0}}}\]                                   done clear
  B)
  \[\frac{2q}{{{\varepsilon }_{0}}}\] done clear
  C)
  \[\frac{q}{2{{\varepsilon }_{0}}}\]                                 done clear
  D)
  zero done clear
  View Solution play_arrow

• question_answer67)

  Direction Q.41 to 45

  Surface charge density is defined as charge per unit da surface area of surface charge distribution i.e., \[\sigma =\frac{dq}{ds}\].

  Two large, thin metal plates are parallel and close to each other. On their inner faces, the plates have surface charge densities of opposite signs having magnitude of \[17.0\times {{10}^{-22}}\,C{{m}^{-2}}\]as shown. The intensity of electric field at a point is\[E=\frac{\sigma }{{{\varepsilon }_{0}}}\], where \[{{\varepsilon }_{0}}\]= permittivity of free space.

  Read the above passage carefully and give the answer of the following questions.

  E in the outer region of the first plate is:
  A)
  \[17\times {{10}^{-22}}N/C\]    done clear
  B)
  \[1.5\times {{10}^{-25}}N/C\] done clear
  C)
  \[1.9\times {{10}^{-10}}N/C\] done clear
  D)
  zero done clear
  View Solution play_arrow

• question_answer68)
  E is the outer region of the second plate is:
  A)
  \[17\times {{10}^{-22}}N/C\] done clear
  B)
  \[1.5\times {{10}^{-15}}N/C\] done clear
  C)
  \[1.9\times {{10}^{-10}}N/C\] done clear
  D)
  zero done clear
  View Solution play_arrow

• question_answer69)
  E between the plates is:
  A)
  \[17\times {{10}^{-22}}N/C\] done clear
  B)
  \[1.5\times {{10}^{-15}}N/C\] done clear
  C)
  \[1.9\times {{10}^{-10}}N/C\] done clear
  D)
  zero done clear
  View Solution play_arrow

• question_answer70)
  The ratio of E from right side of B at distances 2 cm and 4 cm, respectively is: 
  A)
  1 : 2                  done clear
  B)
  2 : 1  done clear
  C)
  1 : 1                 done clear
  D)
  \[1:\sqrt{2}\] done clear
  View Solution play_arrow

• question_answer71)
  In order to estimate the electric field due to a thin finite plane metal plate, the Gaussian surface considered is:
  A)
  spherical              done clear
  B)
  cylindrical done clear
  C)
  straight line           done clear
  D)
  None of these done clear
  View Solution play_arrow

• question_answer72)
             

  Direction Q.46 to 50

  Faraday Cage: A Faraday cage or Faraday shield is an enclosure made of a conducting material. The fields within a conductor cancel out with any external fields, so the electric field within the enclosure is zero. These Faraday cages act as big hollow conductors you can put things into shield them from electrical fields. Any electrical shocks the cage receives, pass harmlessly around the outside of the cage.

  Read the above passage carefully and give the answer of the following questions.

  Which of the following materials can be used to make a Faraday cage? 
  A)
  Plastic                           done clear
  B)
  Glass   done clear
  C)
  Copper             done clear
  D)
  Wood done clear
  View Solution play_arrow

• question_answer73)
  Example of a real-world Faraday cage is:
  A)
  car                                done clear
  B)
  plastic box done clear
  C)
  lightning rod         done clear
  D)
  metal rod done clear
  View Solution play_arrow

• question_answer74)
  What is the electrical force inside a Faraday cage when it is struck by lightning?
  A)
  The same as the lightning done clear
  B)
  Half that of the lightning done clear
  C)
  Zero done clear
  D)
  A quarter of the lightning done clear
  View Solution play_arrow

• question_answer75)
  An isolated point charge +q is placed inside the Faraday cage. Its surface must have charge equal to:
  A)
  zero                   done clear
  B)
  +q       done clear
  C)
  -q                     done clear
  D)
  +2q done clear
  View Solution play_arrow

• question_answer76)
  A point charge of 2 C is placed at centre of Faraday cage in the shape of cube with surface of 9 cm edge. The number of electric field lines passing through the cube normally will be:
  A)
  \[1.9\times {{10}^{5}}\,N{{m}^{2}}/C\]entering the surface done clear
  B)
  \[1.9\times {{10}^{5}}\,N{{m}^{2}}/C\] leaving the surface done clear
  C)
  \[~2.0\text{ }\times \text{ }{{10}^{5}}\text{ }N{{m}^{2}}/C\] leaving the surface done clear
  D)
  \[2.0\text{ }\times \text{ }{{10}^{5}}\text{ }N{{m}^{2}}/C\]entering the surface done clear
  View Solution play_arrow