NEET Electromagnetic Induction — Set 25

Question 1

A coil of 60 turns and area 0.04 m² is in a 0.1 T field that drops to zero in 0.2 s. What is the induced emf?

Accepted Answer

$ \Delta \Phi = B A = 0.1 \times 0.04 = 0.004 \, \text{Wb} $. $ \varepsilon = N \frac{\Delta \Phi}{\Delta t} = 60 \times \frac{0.004}{0.2} = 60 \times 0.02 = 1.2 \, \text{V} $.

Question 2

In a system of two coils, the mutual inductance depends on which property of the setup?

Accepted Answer

Mutual inductance depends on the geometry (e.g., coil sizes, separation, orientation) and the medium’s permeability, affecting how much flux from one coil links with the other.

Question 3

In an AC generator, what happens to the induced emf when the rotational speed of the coil doubles?

Accepted Answer

The emf is proportional to the angular speed ($ \varepsilon = N B A \omega $), so doubling the rotational speed doubles the emf.

NEET Physics: Electromagnetic Induction — Practice Set 25

Q1. A coil of 60 turns and area 0.04 m² is in a 0.1 T field that drops to zero in 0.2 s. What is the induced emf?

Q2. In a system of two coils, the mutual inductance depends on which property of the setup?

Q3. In an AC generator, what happens to the induced emf when the rotational speed of the coil doubles?

Q4. A metal ring is placed in a uniform magnetic field perpendicular to its plane. If the field strength decreases, the induced current in the ring flows in a direction to produce a magnetic field that does what?

Q5. A coil of 180 turns and area 0.02 m² is rotated at 45 Hz in a 0.08 T field. What is the maximum emf?

Q6. A solenoid of 450 turns and length 0.9 m induces an emf of 1.8 V in a nearby coil when its current changes from 2 A to 5 A in 0.3 s. What is the mutual inductance?

Q7. A coil of 80 turns and area 0.05 m² is in a 0.1 T field that drops to zero in 0.25 s. What is the induced emf?

Q8. A circular coil of radius 10 cm and 220 turns rotates at 60 rad/s in a 0.02 T field. What is the maximum emf induced?

Q9. A coil of self-inductance 0.6 H has its current decreased from 4 A to 1 A in 0.15 s. What is the magnitude of the induced emf?

Q10. A solenoid of 800 turns per meter and area 0.013 m² has a current change from 9 A to 6 A in 0.2 s. What is the self-induced emf? (\( \mu_0 = 4\pi \times 10^{-7} \, \text{H/m} \))