NEET (UG)

Practice Test 1 — Electromagnetic Induction

12 questions • 18 minutes • auto-graded with full solutions

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Section A — MCQ (Single Correct)

Question 1

Magnetic flux is maximum through a loop when its plane is:

Solution: Flux $= BA\cos\theta$ is maximum when the plane is perpendicular to $B$ ($\theta = 0$ between $B$ and the normal).

Question 2

The induced EMF depends on the:

Solution: $\varepsilon = -d\Phi/dt$.

Question 3

The negative sign in Faraday's law expresses:

Solution: It encodes Lenz's law (opposition).

Question 4

A rod of length $L$ moving at speed $v$ perpendicular to field $B$ develops EMF:

Solution: $\varepsilon = BLv$.

Question 5

Self-inductance of a solenoid is proportional to:

Solution: $L \propto N^2$.

Question 6

The energy stored in an inductor of inductance $L$ carrying current $I$ is:

Solution: $U = \tfrac{1}{2}LI^2$.

Question 7

Eddy current losses are reduced by:

Solution: Lamination breaks up eddy-current paths.

Question 8

The peak EMF of an AC generator equals:

Solution: $\varepsilon_0 = NBA\omega$.

Section B — Assertion & Reason

Question 9

A: When a magnet is pushed towards a coil, the coil opposes its approach.
R: The induced current flows so as to oppose the change in flux (Lenz's law).

Solution: Lenz's law makes the near face repel the approaching magnet — R explains A.

Question 10

A: The cores of transformers are laminated.
R: Lamination reduces the energy lost to eddy currents in the core.

Solution: Lamination is done precisely to cut eddy-current loss — R explains A.

Question 11

A: The current through an inductor can change instantaneously.
R: An inductor opposes any change in the current through it.

Solution: Current through an inductor cannot jump instantly, so A is false; R correctly states it opposes current change.

Question 12

A: An induced EMF can appear in a coil even when no battery is connected to it.
R: A changing magnetic flux through the coil induces an EMF by Faraday's law.

Solution: A changing flux alone induces an EMF — R explains A.