12th Class Physics Alternating Current / प्रत्यावर्ती धारा Question Bank

done Assertion And Reason (MCQs) - Alternating Currents Total Questions - 34

• 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]: An alternating current does not show any magnetic effect.

  Reason (R): Alternating current does not vary with 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_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]: Average value of AC over a complete cycle is always zero.

  Reason (R): Average value of AC is always defined over half cycle.

  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]: The DC and AC both can be measured by a hot wire instrument.

  Reason (R): The hot wire instrument is based on the principle of magnetic effect of current.

  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]: AC is more dangerous than DC.

  Reason (R): Frequency of AC is dangerous for human body.

  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]: Long distance transmission of AC is carried out at extremely high voltage.

  Reason (R): For Large distance, voltage has to be large.

  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 capacitive reactance limits the amplitude of the current in a purely capacitive circuit.

  Reason (R): Capacitive reactance is proportional to the frequency and the capacitance.

  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]: Capacitor serves as a block for DC and offers an easy path to AC.

  Reason (R): Capacitive reactance is inversely proportional to frequency.

  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]: When capacitive reactance is smaller than the inductive reactance in LCR series circuit, e.m.f. leads the current.

  Reason (R): The phase angle is the angle between the alternating e.m.f. and alternating current of the circuit.

  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]: The inductive reactance limits amplitude of the current in a purely inductive circuit.

  Reason (R): The inductive reactance is independent of the frequency of the current.

  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]: An inductance and a resistance are connected in series with an AC circuit. In this circuit the current and the potential difference across the resistance lags behind potential difference across the inductance by an angle \[\pi /2\].

  Reason (R): In L – R circuit voltage leads the current by phase angle which depends on the value of inductance and resistance both.

  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]: Capacitor serves as a block for DC and offers an easy path to AC.

  Reason (R): Capacitive reactance is inversely proportional to frequency.

  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]: If the frequency of alternating current in an AC circuit consisting of an inductance coil is increased, then current gets decreased.

  Reason (R): The current is inversely proportional to frequency of alternating current.

  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]: When capacitive reactance is smaller than the inductive reactance in LCR current, e.m.f. Leads the current.

  Reason (R): The phase angle is the angle between the alternating e.m.f. and alternating current of the circuit.

  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]: A capacitor of suitable capacitance can be used in an AC circuit in place of the choke coil

  Reason (R): A capacitor blocks DC and allows AC only.

  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]: In series LCR resonance circuit, the impedance is equal to the ohmic resistance.

  Reason (R): At resonance, the inductive reactance exceeds the capacitive reactance.

  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 purely inductive or capacitive circuit, the current is referred to as wattless current.

  Reason (R): No power is dissipated in a purely inductive or capacitive circuit even though a current is flowing in the circuit.

  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]: The only element that dissipates energy in an AC circuit is the resistive element.

  Reason (R): There are no power losses associated with pure capacitances and pure inductances in an AC circuit.

  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]: The power in an AC circuit is minimum, if the circuit has only a resistor.

  Reason (R): Power of a circuit is independent of the phase angle.

  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]: Resonance is exhibited by a circuit only, if both L and C are present in the circuit.

  Reason (R): Only then the voltage across L and C cancel each other, both being out of phase.

  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]: An electric heater is heated first by direct and then by alternating currents. For both the currents, the potential difference across the ends of the heater is the same. The rate of production of heat will be different in two cases.

  Reason (R): The resistance of a coil in alternating current will be more than the resistance of a coil in direct current, hence heat produced in case of direct current will be low.

  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 series LCR circuit resonance can take place.

  Reason (R): Resonance takes place if inductance and capacitive reactances are equal and opposite.

  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 AC Lags behind the e.m.f. by a phase angle of \[\pi /2\], when AC flows through an inductor.

  Reason (R): The inductive reactance increases as the frequency of AC source decreases.

  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]: An electric lamp connected in series with a variable capacitor and AC source, its brightness increases with increase in capacitance.

  Reason (R): Capacitive reactance decreases with increase in capacitance of capacitor.

  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]: At resonance, LCR series circuit have a maximum current.

  Reason (R): At resonance, in LCR series circuit, the current and e.m.f. are in phase with 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_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]: When a current flows in the coil of a transformer then its core becomes hot.

  Reason (R): The core of transformer is made of softiron.

  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]: An ideal transformer does not vary the power.

  Reason (R): A transformer is used to step-up or step-down AC voltages.

  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)

  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 step-up transformer changes a low voltage into a high voltage.

  Reason (R): This violate the Law of conservation of energy.

  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_answer28)

  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 given transformer can be used to step-up or step-down the voltage.

  Reason (R): The output voltage depends upon the ratio of the number of turns of the two coils of the transformer.

  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_answer29)

  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 Laminated core is used in transformers to increase eddy currents.

  Reason (R): The efficiency of a transformer increases with increase in eddy currents.

  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_answer30)

  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 transformer cannot work on DC supply.

  Reason (R): DC changes neither in magnitude nor in direction.

  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_answer31)

  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]: Step-down transformer increases the current.

  Reason (R): Transformer obeys the law of conservation of energy.

  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_answer32)

  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]: Soft iron is used as a core of transformer.

  Reason (R): Area of hysteresis Loop for soft iron is small.

  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_answer33)

  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 core of transformer is made laminated in order to increase the eddy currents.

  Reason (R): The sensitivity of transformer increases with increase in the eddy currents.

  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_answer34)

  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]: We use a thick wire in the secondary coil of a step down transformer to reduce the production of heat.

  Reason (R): When the plane of the armature is parallel to the line of force of magnetic field, the magnitude of induced e.m.f,

  is maximum.
  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