A body cools from \[100{}^\circ C\] to \[90{}^\circ C\] in 20 min, it will cool down from \[110{}^\circ C\] to \[100{}^\circ C\] in [Assume same surroundings]
Consider two observers moving with respect to each other at a speed v along a straight line. They observe a block of mass m moving a distance I on a rough surface. The following quantities will be same as observed by the two observers
An astronaut has left the international space station to test a new space scooter. His partner measures the following velocity changes which take place in 10 s interval. Find the magnitude and direction of average acceleration. At the beginning of 10 s interval the astronaut is moving towards positive x-axis at 10 m/s and at the end of, 10 s he is moving towards negative x-axis at 5 m/s.
A particle of mass 10 kg starts from point A, with an initial velocity of 3m/s towards negative x-axis, it has been acted by a force of 10 N towards positive x-axis. Find the distance travelled by particle in 4 s.
A uniform slender rod 1m long is initially standing vertically on a smooth, horizontal surface. It is struck by a sharp horizontal blow at the top end, with the blow directed at right angles to the rod axis. As a result, the rod acquires an angular velocity of 3.00 rad/s. What is the translational velocity of the centre of mass of the rod after the blow?
During the discharging of battery, the battery supplies electrical energy at the rate of \[VI=EI-{{I}^{2}}r\]. Here, El represent the rate at which non-electrical energy is converted to electrical energy
doneclear
B)
During the charging of battery, the battery consumes energy at the rate of \[VI=EI+{{I}^{2}}r\]. Here, El represents the rate at which electrical energy is converted to non-electrical energy
doneclear
C)
In both the above cases the term \[{{I}^{2}}r\]represents the rate of dissipation of energy in the internal resistance of battery
A 0.5 kg ball is dropped from rest at a point 1.20 m above the floor. The ball rebounds straight upward to a height of 0.7 m. What is the magnitude and the direction of the impulse of the net force applied to the ball during the collision with the floor?
A body is moving with uniform speed v in a horizontal circle in anticlockwise direction as shown in figure. The motion starts from point A, find the change in velocity in second quarter of revolution.
The block which is moving with constant speed 4 m/s with respect to ground is observed from two reference frames A and B. The frame A is non-inertial while B is inertial, then
A)
acceleration of block, with respect to A as well as with respect to B is zero
doneclear
B)
acceleration of block, with respect to A is non-zero while with respect to B is zero
doneclear
C)
acceleration of block with respect to A may be zero while with respect to B may be non-zero
doneclear
D)
acceleration of block with respect to both reference frames A and B would be non-zero
N moles of an ideal diatomic gas are in a cylinder at temperature T. If we supply some heat to; it, then N/3 moles of gas dissociates into atoms while temperature remains constant. Heat supplied to the gas is
Electrons having KE 15 eV is collided with hydrogen atom and 80.6% of it is used to excite the electrons from its ground state. Find the number of emitted wavelengths.
A pistol fires a 3g bullet with a speed of 400 m/s. The pistol barrel is 13 cm long. How (much energy is given to the bullet? Also, calculate the average force acted on the bullet while it was moving down the barrel.
A person of mass m is standing a on a structure made up of pulley, strings and platform as shown in figure. Find the force exerted by the person on the rope, so that the system (person structure) remains in equilibrium.
\[{{\text{X}}_{\text{ }\!\!\beta\!\!\text{ }}}\]X-ray of argon has wavelength 0.36 nm, the minimum energy needed to ionize an argon atom is 16 eV. Find the energy needed to knock out an electron from K shell of an argon atom.
Directions: Assertion - Reaction type. Each of these contains tow statements: Statement I (Assertion), Statement II (Reason). Each of these questions also has four alternative choices, only one of which is correct. You have to select the correct choices from the codes (a), (b), (c) and (d) given below:
Statement I: When speed of projection of a body is made n times, its time of flight becomes n times.
Statement II: At this speed the range of projectile becomes n times.
A)
Statement I is true; Statement II is true; Statement II is not a correct explanation for Statement I,
doneclear
B)
Statement I is true; Statement II is false.
doneclear
C)
Statement I is false; Statement II is true.
doneclear
D)
Statement I is true; Statement II is true; Statements is the correct explanation for Statement I.
Directions: Assertion - Reaction type. Each of these contains tow statements: Statement I (Assertion), Statement II (Reason). Each of these questions also has four alternative choices, only one of which is correct. You have to select the correct choices from the codes (a), (b), (c) and (d) given below:
Statement I: No diffraction is produced in sound waves near a very small opening.
Statement II: For diffraction to take place the aperture of opening should be of the same order as wavelength of the waves.
A)
Statement I is true; Statement II is true; Statement II is not a correct explanation for Statement I,
doneclear
B)
Statement I is true; Statement II is false.
doneclear
C)
Statement I is false; Statement II is true.
doneclear
D)
Statement I is true; Statement II is true; Statements is the correct explanation for Statement I.
Two identical p-n junctions may be connected in series with a battery in three ways as shown in figure. The potential differences across the two p-n junctions are equal in
The electric field associated with a monochromatic beam becomes zero 2.4 x 1015 times per second. Find the maximum KE of the photoelectrons when this light falls on a metal surface whose work function is 2 eV.
A radioactive sample whose half-life is 40 h has 18 times too much activity for safety, then after how many half-lives will the radioactive sample will be safe?
Direction: Question based on the following paragraph.
Two rods 1 and 2 are released from rest as shown in figure.
Given:\[{{l}_{1}}=4l,{{m}_{1}}=2m,{{l}_{2}}=2l\]and\[{{m}_{2}}=m.\]There is no friction between the two rods. If \[\alpha \]be the angular acceleration of rod 1 just after the rods are released. Then
What is the normal reaction between the two rods at this instant?
Direction: Question based on the following paragraph.
Two rods 1 and 2 are released from rest as shown in figure.
Given:\[{{l}_{1}}=4l,{{m}_{1}}=2m,{{l}_{2}}=2l\]and\[{{m}_{2}}=m.\]There is no friction between the two rods. If \[\alpha \]be the angular acceleration of rod 1 just after the rods are released. Then
What is the horizontal force on rod 1 by hinge A at this instant?
Direction: Question based on the following paragraph.
Two rods 1 and 2 are released from rest as shown in figure.
Given:\[{{l}_{1}}=4l,{{m}_{1}}=2m,{{l}_{2}}=2l\]and\[{{m}_{2}}=m.\]There is no friction between the two rods. If \[\alpha \]be the angular acceleration of rod 1 just after the rods are released. Then
What is initial angular acceleration of rod 2 in terms of the given parameters in the question?
For the given combination of gates, if the logic states of inputs A, B, C are as follows A = B = C = 0 and A = 5 = 1, C = 0, then the logic states of output D are
A person tries to find the value of unknown resistance using potentiometer as shown in the diagram below. He uses a resistance of \[5\Omega ,\]unknown resistance X and a battery of 5 V in secondary circuit. He touches the jockey\[{{\text{J}}_{\text{1}}}\]on potentiometer wire to get the point P, so that there is no deflection in \[{{G}_{1}}\] then he locates the point Q, so that \[{{G}_{2}}\] shows zero deflection. It is found that \[AP=\frac{AQ}{3}.\] Value of X is
A rain drop of radius 0.2 cm is falling through air with a terminal velocity of 8.7 m/s. The viscosity of air in SI units is [Take \[{{\text{ }\!\!\rho\!\!\text{ }}_{\text{water}}}\] = 1000 kg/m3 and \[{{\text{ }\!\!\rho\!\!\text{ }}_{\text{air}}}=1\text{kg/}{{\text{m}}^{\text{3}}}]\]
For the reaction \[A+BC+D,\]equilibrium concentration of [C] =[D] = 0.5M if we start with 1 mole each of A and B. Percentage of A converted into C if we start with 2 moles of A and 1 mole of B, is
The molecule \[B{{F}_{3}}\] and \[N{{F}_{3}}\] both are covalent compounds, but \[B{{F}_{3}}\]is non-polar and \[N{{F}_{3}}\]is polar. The reason is that
A)
boron is a metal and nitrogen is a gas in uncombined state
doneclear
B)
\[B{{F}_{3}}\] bonds have no dipole moment whereas \[N{{F}_{3}}\] bond have dipole moment
doneclear
C)
atomic size of boron is smaller than that of nitrogen
doneclear
D)
\[B{{F}_{3}}\] is symmetrical molecule whereas \[N{{F}_{3}}\]is unsymmetrical?
\[X\xleftarrow[{{H}_{2}}S{{O}_{4}},{{H}_{2}}O]{HgS{{O}_{4}}}\]1-pentyne\[\xrightarrow[OH_{,}^{-}{{H}_{2}}{{O}_{2}}]{B{{H}_{3}},THF}Y\]X and V cannot be distinguished by
Direction: Assertion- Reaction type. Each of these contains tow statements: Statement I (Assertion), Statement II (Reason). Each of these questions also has four alternative choices, only one of which is correct. You have to select the correct choices from the codes (a), (b), (c) and (d) given below:
Statement I: N-atom in \[N{{H}_{3}}\] is \[s{{p}^{3}}\]hybridized and bond angle is \[107{}^\circ \].
Statement II: \[lp-bp\] repulsion (VSEPR) decreases bond angle to \[107{}^\circ \].
A)
Statement I is true; Statement II is true; Statement II is not a correct explanation for Statement I,
doneclear
B)
Statement I is true; Statement II is false.
doneclear
C)
Statement I is false; Statement II is true.
doneclear
D)
Statement I is true; Statement II is true; Statements is the correct explanation for Statement I.
Direction: Assertion- Reaction type. Each of these contains tow statements: Statement I (Assertion), Statement II (Reason). Each of these questions also has four alternative choices, only one of which is correct. You have to select the correct choices from the codes (a), (b), (c) and (d) given below:
Statement I: In vulcanisation of rubber, sulphur cross links are introduced.
Statement II: Vulcanisation is a free radical initiated chain reaction.
A)
Statement I is true; Statement II is true; Statement II is not a correct explanation for Statement I,
doneclear
B)
Statement I is true; Statement II is false.
doneclear
C)
Statement I is false; Statement II is true.
doneclear
D)
Statement I is true; Statement II is true; Statements is the correct explanation for Statement I.
Total entropy change for a system which is not isolated from the surroundings is given by \[\Delta {{S}_{total}}=\Delta {{S}_{system}}+\Delta {{S}_{surroundings}}.\]For the spontaneous process
A)
\[\Delta {{S}_{total}}=0,\] always
doneclear
B)
\[\Delta {{S}_{total}}=\] positive, always
doneclear
C)
\[\Delta {{S}_{total}}=\] negative, always
doneclear
D)
\[\Delta {{S}_{total}}\] will be positive or negative other than zero
The osmotic pressure of blood is 7.65 atm at \[37{}^\circ C\]. How much glucose should be used per litre for an intravenous injection that is to have the same osmotic pressure as blood?
\[\Delta {{S}^{o}},\]change in entropy for the following cell reaction is \[2{{H}_{2}}+{{O}_{2}}\to 2{{H}_{2}}O\](Given :\[{{E}^{o}}_{cell}=1.23V,\] \[\Delta H_{f}^{o}({{H}_{2}}O)=-285.8\,\text{kJ}\,\text{mo}{{\text{l}}^{-1}}\],\[\Delta {{G}^{o}}=-\,474.78\text{kJ}\,)\]
A metal X on heating in nitrogen gas gives Y. Y on treatment with H-f) gives a colourless gas which when passed through \[CuS{{O}_{4}}\] solution gives a blue colour. Y is
If one litre of air is passed repeatedly over heated copper and magnesium till no further reduction in volume takes place, the volume finally obtained would be approximately
The compound 'X yeas boiled under reflux for some time with a solution of sodium hydroxide. The solution was cooled, acidified with dilute nitric acid and then silver nitrate solution was added, a thick precipitate was formed, which one is incorrect as 'X' ?
In the reaction sequence\[X\xrightarrow[{}]{Ca{{(OH)}_{2}}}Y\xrightarrow[distillation]{Dry}Actetone\xrightarrow[{{H}_{2}}S{{O}_{4}}]{Conc.}Z;\]X. V and Z are
To a 25 mL HaOa solution, excess of acidified solution of potassium iodide was added. The iodine liberated required 20 mL of 0.3 N sodium thiosulphate solution. The volume strength of \[{{H}_{2}}{{O}_{2}}\] solution is
In a certain polluted atmosphere containing 03 at a steady state concentration of \[2.0\times {{10}^{-8}}\text{mol/L,}\] the hourly production of 03 by all sources was estimated as \[7.2\times {{10}^{-15}}\text{mol/L}\]. If the only mechanism for destruction of \[{{O}_{3}}\] is the second order reaction\[2{{O}_{3}}\to 3{{O}_{2}},\]what is the rate constant for the destruction reaction?
The chemical reaction \[2{{O}_{3}}\to 3{{O}_{2}}\] proceeds as follows \[{{O}_{3}}{{O}_{2}}+O\] .... (fast)\[O+{{O}_{3}}\to 2{{O}_{2}}\].... (slow), the rate law expression should be
Directions: The decarboxylation of aromatic acids is most often carried out by heating with Cu-quinoline \[ArCOOH\xrightarrow[{}]{Cu-quinoline}ArH+C{{O}_{2}}\] Cuprous salts of aromatic acids, actually undergoes decarboxylation. However, two other methods can be used with certain substrates.
Method 1: Salt of acid, \[ArCO{{O}^{-}}\]is heated (SE1)
Step I:
Step II:
Method II: Carboxylic acid is heated with a strong acid, often sulphuric acid.
Decarboxylation takes place by the arenium ion mechanism, with\[{{\text{H}}^{+}}\] electrophile. Evidently, the order of electrofugal ability is \[C{{O}_{2}}>{{H}^{+}}>COO{{H}^{+}}\]Rearrangements are also known to take place. For example,, when the phthalate ion is heated with catalytic amount of cadmium, the terephthalate ion is produced. In a similar process, potassium benzoate heated with cadmium salts disproportionates. The rearrangement is named as 'Henkel rearrangement'.
Mark out the correct order of -G (functional group) according to their ease to facilitate the decarboxylation reaction.
Directions: The decarboxylation of aromatic acids is most often carried out by heating with Cu-quinoline \[ArCOOH\xrightarrow[{}]{Cu-quinoline}ArH+C{{O}_{2}}\] Cuprous salts of aromatic acids, actually undergoes decarboxylation. However, two other methods can be used with certain substrates.
Method 1: Salt of acid, \[ArCO{{O}^{-}}\]is heated (SE1)
Step I:
Step II:
Method II: Carboxylic acid is heated with a strong acid, often sulphuric acid.
Decarboxylation takes place by the arenium ion mechanism, with\[{{\text{H}}^{+}}\] electrophile. Evidently, the order of electrofugal ability is \[C{{O}_{2}}>{{H}^{+}}>COO{{H}^{+}}\]Rearrangements are also known to take place. For example,, when the phthalate ion is heated with catalytic amount of cadmium, the terephthalate ion is produced. In a similar process, potassium benzoate heated with cadmium salts disproportionates. The rearrangement is named as 'Henkel rearrangement'.
Mark out the correct order of -G (functional group) according to their ease to facilitate the decarboxylation reaction.
Directions: The decarboxylation of aromatic acids is most often carried out by heating with Cu-quinoline \[ArCOOH\xrightarrow[{}]{Cu-quinoline}ArH+C{{O}_{2}}\] Cuprous salts of aromatic acids, actually undergoes decarboxylation. However, two other methods can be used with certain substrates.
Method 1: Salt of acid, \[ArCO{{O}^{-}}\]is heated (SE1)
Step I:
Step II:
Method II: Carboxylic acid is heated with a strong acid, often sulphuric acid.
Decarboxylation takes place by the arenium ion mechanism, with\[{{\text{H}}^{+}}\] electrophile. Evidently, the order of electrofugal ability is \[C{{O}_{2}}>{{H}^{+}}>COO{{H}^{+}}\]Rearrangements are also known to take place. For example,, when the phthalate ion is heated with catalytic amount of cadmium, the terephthalate ion is produced. In a similar process, potassium benzoate heated with cadmium salts disproportionates. The rearrangement is named as 'Henkel rearrangement'.
In the 'Henkel reaction' when potassium benzoate is heated with cadmium salts, the products are
If \[{{x}_{1}},{{x}_{2}},{{x}_{3}}\]as well as \[{{y}_{1}},{{y}_{2}},{{y}_{3}}\]are in GP with the same common ratio, then the points\[({{x}_{1}},{{y}_{1}}),({{x}_{2}},{{y}_{2}})\]and \[({{x}_{1}},{{y}_{1}}),({{x}_{2}},{{y}_{2}})\]
Let \[\overrightarrow{a},\overrightarrow{b},\overrightarrow{c}\] three vectors such that \[\overrightarrow{a}\ne 0\] and \[\overrightarrow{a}\times \overrightarrow{b}=2\overrightarrow{a}\times \overrightarrow{c},\]\[|\overrightarrow{a}|=|\overrightarrow{c}|=1,\]\[|\overrightarrow{b}|=4\]and \[|\overrightarrow{b}\times \overrightarrow{c}|=\sqrt{15}.\]If \[\overrightarrow{b}-2\overrightarrow{c}=\lambda \overrightarrow{a},\]then \[\lambda \] is equal to
Eight chairs are numbered 1 to 8. Two women and three men wish to occupy one chair each. First the women choose the chairs from amongst the chairs marked 1 to 4 and then the men select the chairs from amongst the remaining. The number of possible arrangements is
Direction: Assertion- Reaction type. Each of these contains tow statements: Statement I (Assertion), Statement II (Reason). Each of these questions also has four alternative choices, only one of which is correct. You have to select the correct choices from the codes [a], [b], [c] and [d] given below:
Statement I: A coin is tossed 31 times. If the probability of getting number of heads more than the number of tails is equal to the probability of getting tails more than the number of heads, then the coin must be unbiased.
Statement II: If p = q and p + q = 1, then coin is unbiased.
A)
Statement I is true; Statement II is true; Statement II is not a correct explanation for Statement I
doneclear
B)
Statement I is true; Statement II is false.
doneclear
C)
Statement I is false; Statement II is true.
doneclear
D)
Statement I is true; Statement II is true; Statements is the correct explanation for Statement I.
Direction: Assertion- Reaction type. Each of these contains tow statements: Statement I (Assertion), Statement II (Reason). Each of these questions also has four alternative choices, only one of which is correct. You have to select the correct choices from the codes [a], [b], [c] and [d] given below:
Statement I: If f(x) is odd function and g(x) is even function, then f(x)+ g(x) is neither even no odd.
Statement II: Odd function is symmetrical at in opposite quadrants and even function is symmetrical about the y-axis.
A)
Statement I is true; Statement II is true; Statement II is not a correct explanation for Statement I
doneclear
B)
Statement I is true; Statement II is false.
doneclear
C)
Statement I is false; Statement II is true.
doneclear
D)
Statement I is true; Statement II is true; Statements is the correct explanation for Statement I.
Direction: Assertion- Reaction type. Each of these contains tow statements: Statement I (Assertion), Statement II (Reason). Each of these questions also has four alternative choices, only one of which is correct. You have to select the correct choices from the codes [a], [b], [c] and [d] given below:
Statement I: If normal at the ends of double ordinate x = 4 of parabola y2 = 4x meet the curve again at P and P' respectively, then PP' = 12unit.
Statement II: If normal at \[{{\text{t}}_{\text{1}}}\] of y2 = 4ox meet the parabola again at \[{{\text{t}}_{2}},\] then \[{{\text{t}}_{2}}=-{{t}_{1}}\frac{2}{{{t}_{1}}}.\]
A)
Statement I is true; Statement II is true; Statement II is not a correct explanation for Statement I
doneclear
B)
Statement I is true; Statement II is false.
doneclear
C)
Statement I is false; Statement II is true.
doneclear
D)
Statement I is true; Statement II is true; Statements is the correct explanation for Statement I.
10 different toys are to be distributed among 10 children. Total number of ways of distributing these toys, so that exactly 2 children do not get any toy, is equal to
If\[{{(1+x)}^{n}}=\sum\limits_{r=0}^{n}{^{n}{{C}_{r}}\,{{x}^{n}},}\]then\[\frac{^{n}{{C}_{0}}}{1.2}{{2}^{2}}+\frac{^{n}{{C}_{1}}}{2.3}{{2}^{3}}+\frac{^{n}{{C}_{2}}}{3.4}{{2}^{4}}+...\]\[+\frac{^{n}{{C}_{2}}}{(n+1).(n+2)}{{2}^{n+2}}\]is equal to
A parallelepiped is formed by planes drawn through the points (2, 3, 5) and (5, 9, 7), parallel to the coordinate planes. The length of a diagonal of the parallelepiped is
If\[a>2b>0,\]then positive value of m for which \[y=mx-b\sqrt{1+{{m}^{2}}}\]is a common tangent to \[{{x}^{2}}+{{y}^{2}}={{b}^{2}}\]and \[{{(x-a)}^{2}}+{{y}^{2}}={{b}^{2}},\]is
If \[{{a}_{r}}>0,r\in N\]and \[{{a}_{1}},{{a}_{2}}....,{{a}_{2n}}\]are in AP, then\[\frac{{{a}_{1}}+{{a}_{2n}}}{\sqrt{{{a}_{1}}}+\sqrt{{{a}_{2}}}}+\frac{{{a}_{2}}+{{a}_{2n+1}}}{\sqrt{{{a}_{2}}}+\sqrt{{{a}_{3}}}}+\frac{{{a}_{3}}+{{a}_{2n-2}}}{\sqrt{{{a}_{3}}}+\sqrt{{{a}_{4}}}}+....+\]\[\frac{{{a}_{n}}+{{a}_{n+1}}}{\sqrt{{{a}_{n}}}+\sqrt{{{a}_{n+1}}}}\]
PQ and RS are two perpendicular chords of the rectangular hyperbola If C is the centre of the rectangular hyperbola, then the product of the slopes of CP, CQ, CR and CS is equal to