NEET Electromagnetic Induction — Set 12

Question 1

A rectangular loop of 0.36 m × 0.5 m moves out of a 0.55 T field at 0.8 m/s along its shorter side. What is the emf?

Accepted Answer

$ \varepsilon = B l v $, $ l = 0.5 \, \text{m} $. $ \varepsilon = 0.55 \times 0.5 \times 0.8 = 0.22 \, \text{V} $.

Question 2

A wheel with 10 spokes of 0.7 m each rotates at 60 rpm in a 0.5 T field. What is the induced emf?

Accepted Answer

$ \omega = 2\pi \times \frac{60}{60} = 2\pi \, \text{rad/s} $. $ \varepsilon = \frac{1}{2} B \omega R^2 = \frac{1}{2} \times 0.5 \times 2\pi \times (0.7)^2 = 0.7697 \, \text{V} \approx 0.77 \, \text{V} $.

Question 3

A coil of self-inductance 0.4 H has its current decreased from 5 A to 2 A in 0.1 s. What is the magnitude of the induced emf?

Accepted Answer

$ \varepsilon = -L \frac{\Delta I}{\Delta t} $. $ \Delta I = 2 - 5 = -3 \, \text{A} $, $ \Delta t = 0.1 \, \text{s} $. $ \varepsilon = 0.4 \times \frac{-3}{0.1} = 0.4 \times (-30) = -12 \, \text{V} $. Magnitude = 12 V.

NEET Physics: Electromagnetic Induction — Practice Set 12

Q1. A rectangular loop of 0.36 m × 0.5 m moves out of a 0.55 T field at 0.8 m/s along its shorter side. What is the emf?

Q2. A wheel with 10 spokes of 0.7 m each rotates at 60 rpm in a 0.5 T field. What is the induced emf?

Q3. A coil of self-inductance 0.4 H has its current decreased from 5 A to 2 A in 0.1 s. What is the magnitude of the induced emf?

Q4. A square loop of side 26 cm rotates at 12 rad/s in a 0.3 T field. What is the maximum emf induced?

Q5. A solenoid with mutual inductance 0.25 H has a current change of 6 A/s in the primary coil. What is the induced emf in the secondary coil?

Q6. A loop of 0.32 m × 0.16 m moves out of a 0.35 T field at 2 m/s along its longer side. How long does the emf last?

Q7. A rectangular loop of 0.24 m × 0.38 m moves out of a 0.3 T field at 0.6 m/s along its shorter side. What is the emf?

Q8. A solenoid’s current is increased, and the energy stored in its magnetic field increases. This energy is analogous to what mechanical quantity?

Q9. A conducting loop is shrunk in a uniform magnetic field. The induced current flows in a direction to oppose what change?

Q10. A loop of 0.35 m × 0.1 m moves out of a 0.25 T field at 2.5 m/s along its longer side. How long does the emf last?