NEET Electromagnetic Induction — Set 4

Question 1

A conducting rod slides along parallel rails in a magnetic field perpendicular to its motion. The emf induced in the circuit is classified as what type?

Accepted Answer

This is motional emf, as it arises from the rod’s motion through the magnetic field, cutting flux lines to induce a potential difference.

Question 2

A solenoid of 950 turns/m and area 0.012 m² has $ \mu_r = 1 $. What is its self-inductance? ($ \mu_0 = 4\pi \times 10^{-7} \, \text{H/m} $)

Accepted Answer

$ L = \mu_r \mu_0 n^2 A l $, assume $ l = 1 \, \text{m} $. $ L = 1 \times 4\pi \times 10^{-7} \times (950)^2 \times 0.012 \times 1 = 0.0136 \, \text{H} \approx 0.014 \, \text{H} $.

Question 3

A wheel with 8 spokes of 0.25 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 (0.25)^2 = 0.098 \, \text{V} \approx 0.1 \, \text{V} $.

NEET Physics: Electromagnetic Induction — Practice Set 4

Q1. A conducting rod slides along parallel rails in a magnetic field perpendicular to its motion. The emf induced in the circuit is classified as what type?

Q2. A solenoid of 950 turns/m and area 0.012 m² has \( \mu_r = 1 \). What is its self-inductance? (\( \mu_0 = 4\pi \times 10^{-7} \, \text{H/m} \))

Q3. A wheel with 8 spokes of 0.25 m each rotates at 60 rpm in a 0.5 T field. What is the induced emf?

Q4. A loop enters a magnetic field region with its plane perpendicular to the field. The induced current flows to produce a magnetic field opposing what?

Q5. A coil of 90 turns experiences a magnetic flux change from 0 to 0.025 Wb in 0.05 s. What is the induced emf?

Q6. A solenoid of 850 turns/m and area 0.01 m² has \( \mu_r = 1 \). What is its self-inductance? (\( \mu_0 = 4\pi \times 10^{-7} \, \text{H/m} \))

Q7. A rectangular loop of 0.15 m × 0.25 m moves out of a 0.3 T field at 0.8 m/s along its shorter side. What is the emf?

Q8. A circular coil of radius 5 cm and 300 turns rotates at 35 rad/s in a 0.05 T field. What is the maximum emf induced?

Q9. A conducting loop is moved out of a magnetic field region. The induced current flows to oppose what specific change?

Q10. In an AC generator, the emf varies sinusoidally with time. What is the primary reason for this variation?