Home
Class 12
PHYSICS
Asseration:Lenz's law violates the princ...

Asseration:Lenz's law violates the principle of conservation of energy.
Reason: Induced e.m.f. opposes always the change in magnetic flux responsible for its production.

A

(a) Statement I is True, Staatement II is True, Statement II is correct expaination for Statement I.

B

(b) Statement I is True, Staatement II is True, Statement II is NOT a correct expaination for Statement I.

C

( c) statement I is True, Satement II is false.

D

( d) statement I is False, Satement II is True.

Text Solution

AI Generated Solution

The correct Answer is:
To solve the assertion-reason question, we will analyze both the assertion and the reason step by step. ### Step 1: Analyze the Assertion - **Assertion**: "Lenz's law violates the principle of conservation of energy." - Lenz's law states that the direction of induced current (and thus the induced electromotive force, or e.m.f.) is such that it opposes the change in magnetic flux that produced it. This means that the induced current works against the change, which is a manifestation of energy conservation, not a violation of it. ### Step 2: Analyze the Reason - **Reason**: "Induced e.m.f. opposes always the change in magnetic flux responsible for its production." - This statement is true. According to Lenz's law, the induced e.m.f. does indeed oppose the change in magnetic flux. This opposition is what ensures that energy is conserved in electromagnetic systems. If the induced e.m.f. did not oppose the change, it would lead to a situation where energy could be created from nothing, violating the conservation of energy principle. ### Step 3: Conclusion - Since the assertion is false (Lenz's law does not violate conservation of energy) and the reason is true (the induced e.m.f. opposes the change in magnetic flux), we can conclude that the correct option is: - **Option D**: Assertion is false, but Reason is true. ### Final Answer The correct answer is **Option D**. ---

To solve the assertion-reason question, we will analyze both the assertion and the reason step by step. ### Step 1: Analyze the Assertion - **Assertion**: "Lenz's law violates the principle of conservation of energy." - Lenz's law states that the direction of induced current (and thus the induced electromotive force, or e.m.f.) is such that it opposes the change in magnetic flux that produced it. This means that the induced current works against the change, which is a manifestation of energy conservation, not a violation of it. ### Step 2: Analyze the Reason - **Reason**: "Induced e.m.f. opposes always the change in magnetic flux responsible for its production." ...
Promotional Banner

Topper's Solved these Questions

  • ELECTROMAGNETIC INDUCTION

    CENGAGE PHYSICS ENGLISH|Exercise Exercises Linked Comprehension|36 Videos
  • ELECTROMAGNETIC INDUCTION

    CENGAGE PHYSICS ENGLISH|Exercise Exercises Integer|9 Videos
  • ELECTROMAGNETIC INDUCTION

    CENGAGE PHYSICS ENGLISH|Exercise Exercises Multiple Correct|23 Videos
  • ELECTRICAL MEASURING INSTRUMENTS

    CENGAGE PHYSICS ENGLISH|Exercise M.C.Q|2 Videos
  • ELECTRON,PHONTS,PHOTOELECTRIC EFFECT & X-RAYS

    CENGAGE PHYSICS ENGLISH|Exercise dpp 3.3|15 Videos

Similar Questions

Explore conceptually related problems

Assertion: Faraday's laws are consequences of conservation of energy. Reason: In a purely resistive AC circuit, the current lags behind the e.m.f. in phase

STATEMENT-1: Lenz's law is based on the principle of conservation of energy. Because STATEMENT-2: The magnitude of the induced emf is directly proportional to the rate of change of the magnetic flux.

A : Total induced emf in a loop is not confined to any particular point but it is distributed around the loop in direct proportion to the resistances of its parts. R: In general when there is no change in magnetic flux, no induced emf is produced.

(A) : Self-inductance is called the inertia of electricity. (R) : Self-inductance is the phenomenon, according to which an opposing induced e.m.f. is produced in a coil as a result of change in current or magnetic flux linked with the coil.

Statement-1 : The induced e.m.f. and current will be same in two identical loops of copper and aluminium, when rotated with same speed in the same magnetic field. Statement-2 : Induced e.m.f. is proportional to rate of change of magnetic field while induced current depends on resistance of wire.

The phase difference between the flux linkage and the induced e.m.f. in a rotating coil in a uniform magnetic field

(a) Describe a simple experiment (or activity) to show that the polarity of emf induced in a coil is always such that it tends to produce a current which opposes the change of magnetic flux that produces it. (b) The current flowing through an inductor of self inductance L is continuously increasing. Plot a graph showing the variation of (i) Magnetic flux versus the current (ii) Induced emf versus dI/Dt (iii) Magnetic potential energy stored versus the current.

Asseration: The direction of induced e.m.f. is always such as to oppose the change that causes it. Reason: The direction of induced e.m.f. is given by Lenz's Law.

Asseration: Induced potential across a coil and therefore induced current is always opposite to the direction of current due to external source. Reason: Lenz's law states that it always opposes the cause due to which it is being produced.

Electromagnetic brakes work on the principle of electromagnetic induction. If a metallic disc or a coil is rotating in a uniform magnetic field, it will experience a torque due to induced currents set up in the disc. According to Lenz's law, induced current is in a direction so as to oppose the rotation. Hence a retarding torque is produced. The rotating wheel of a vehicle is connected to a coil placed in a uniform emf is used to charge a battery. Thus kinetic enery of wheel is stored as chemical energy. The drawback of electromagnetic brake is that induced current or retarding torque is directly proportional to speed of rotation. The speed, therefore, decays exponentially and vehicle will take a long time to stop. Thus, mechanical brakes are used simultaneously. The advantage of electromagnetic brakes is that