NEET Electromagnetic Induction — Set 1

Question 1

A rectangular loop of 0.22 m × 0.4 m moves out of a 0.35 T field at 0.5 m/s along its shorter side. What is the emf?

Accepted Answer

$ \varepsilon = B l v $, $ l = 0.4 \, \text{m} $. $ \varepsilon = 0.35 \times 0.4 \times 0.5 = 0.07 \, \text{V} $.

Question 2

A solenoid of 500 turns and length 1 m induces an emf of 1.5 V in a nearby coil when its current changes from 0 to 3 A in 0.2 s. What is the mutual inductance?

Accepted Answer

$ \varepsilon = M \frac{\Delta I}{\Delta t} $. $ \Delta I = 3 - 0 = 3 \, \text{A} $, $ \Delta t = 0.2 \, \text{s} $. $ M = \frac{\varepsilon}{\frac{\Delta I}{\Delta t}} = \frac{1.5}{\frac{3}{0.2}} = \frac{1.5}{15} = 0.1 \, \text{H} $.

Question 3

A solenoid carries a steady current. A second coil placed nearby experiences an emf only when what happens to the current in the solenoid?

Accepted Answer

Emf is induced in the second coil only when the magnetic flux changes, which occurs when the current in the solenoid changes, not when it remains steady.

NEET Physics: Electromagnetic Induction — Practice Set 1

Q1. A rectangular loop of 0.22 m × 0.4 m moves out of a 0.35 T field at 0.5 m/s along its shorter side. What is the emf?

Q2. A solenoid of 500 turns and length 1 m induces an emf of 1.5 V in a nearby coil when its current changes from 0 to 3 A in 0.2 s. What is the mutual inductance?

Q3. A solenoid carries a steady current. A second coil placed nearby experiences an emf only when what happens to the current in the solenoid?

Q4. A solenoid of 650 turns per meter and area 0.014 m² has a current change from 6 A to 3 A in 0.25 s. What is the self-induced emf? (\( \mu_0 = 4\pi \times 10^{-7} \, \text{H/m} \))

Q5. A coil of 150 turns and area 0.06 m² is in a 0.14 T field that drops to zero in 0.3 s. What is the induced emf?

Q6. A rod of length 0.9 m moves at 1.2 m/s in a 0.5 T field perpendicular to its length. What is the induced emf?

Q7. A circular loop of radius 16 cm is deformed into a straight wire in a 0.12 T field in 0.6 s. What is the induced emf?

Q8. A rod of length 0.5 m moves at 3 m/s in a 0.2 T field perpendicular to its length. What is the induced emf?

Q9. A coil of 100 turns experiences a magnetic flux change from 0 to 0.03 Wb in 0.06 s. What is the induced emf?

Q10. A square loop of side 22 cm rotates at 14 rad/s in a 0.15 T field. What is the maximum emf induced?

Q11. A magnet is moved towards a coil with its south pole first. The coil’s face nearest the magnet becomes what pole to oppose the motion?

Q12. A rectangular loop of 0.38 m × 0.55 m moves out of a 0.65 T field at 0.7 m/s along its shorter side. What is the emf?

Q13. A solenoid has 200 turns and length 0.5 m. If the current changes from 2 A to 4 A in 0.2 s in a nearby coil, inducing an emf of 0.5 V, what is the mutual inductance?

Q14. A rectangular loop of sides 35 cm and 15 cm moves out of a 0.8 T field at 1.5 m/s perpendicular to the shorter side. What is the motional emf?

Q15. A coil of 60 turns experiences a magnetic flux change from 0 to 0.015 Wb in 0.03 s. What is the induced emf?