NEET Electromagnetic Induction — Set 8

Question 1

A solenoid of 300 turns and length 0.6 m induces an emf of 0.9 V in a nearby coil when its current changes from 1 A to 3 A in 0.3 s. What is the mutual inductance?

Accepted Answer

$ \varepsilon = M \frac{\Delta I}{\Delta t} $. $ \Delta I = 3 - 1 = 2 \, \text{A} $, $ \Delta t = 0.3 \, \text{s} $. $ M = \frac{\varepsilon}{\frac{\Delta I}{\Delta t}} = \frac{0.9}{\frac{2}{0.3}} = \frac{0.9}{6.67} \approx 0.135 \, \text{H} $.

Question 2

A rectangular loop of sides 45 cm and 25 cm moves out of a 1.0 T field at 0.8 m/s perpendicular to the longer side. What is the motional emf?

Accepted Answer

$ \varepsilon = B l v $, $ l = 0.25 \, \text{m} $. $ \varepsilon = 1.0 \times 0.25 \times 0.8 = 0.2 \, \text{V} $.

Question 3

A solenoid of 400 turns per meter and area 0.015 m² has a current drop from 5 A to 2 A in 0.3 s. What is the self-induced emf? ($ \mu_0 = 4\pi \times 10^{-7} \, \text{H/m} $)

Accepted Answer

$ L = \mu_0 n^2 A l $, assume $ l = 1 \, \text{m} $. $ L = 4\pi \times 10^{-7} \times (400)^2 \times 0.015 \times 1 = 0.003016 \, \text{H} $. $ \varepsilon = L \frac{\Delta I}{\Delta t} = 0.003016 \times \frac{2 - 5}{0.3} = 0.003016 \times (-10) = 0.03016 \, \text{V} \approx 0.03 \, \text{V} $.

NEET Physics: Electromagnetic Induction — Practice Set 8

Q1. A solenoid of 300 turns and length 0.6 m induces an emf of 0.9 V in a nearby coil when its current changes from 1 A to 3 A in 0.3 s. What is the mutual inductance?

Q2. A rectangular loop of sides 45 cm and 25 cm moves out of a 1.0 T field at 0.8 m/s perpendicular to the longer side. What is the motional emf?

Q3. A solenoid of 400 turns per meter and area 0.015 m² has a current drop from 5 A to 2 A in 0.3 s. What is the self-induced emf? (\( \mu_0 = 4\pi \times 10^{-7} \, \text{H/m} \))

Q4. A rectangular loop of sides 12 cm and 4 cm moves out of a 0.35 T field at 2 m/s perpendicular to the longer side. What is the motional emf?

Q5. A coil of 100 turns and area 0.03 m² is in a 0.08 T field that drops to zero in 0.2 s. What is the induced emf?

Q6. A solenoid of 950 turns/m and area 0.016 m² has \( \mu_r = 1 \). What is its self-inductance? (\( \mu_0 = 4\pi \times 10^{-7} \, \text{H/m} \))

Q7. A coil with \( L = 0.25 \, \text{H} \) has its current increased from 0 to 4 A in 0.4 s. What is the energy stored?

Q8. A conducting rod is rotated about one end in a uniform magnetic field. The emf induced between the ends is due to what fundamental effect?

Q9. A solenoid with mutual inductance 0.18 H has a current change of 5 A/s in the primary coil. What is the induced emf in the secondary coil?

Q10. A coil of self-inductance 1.5 H has its current decreased from 7 A to 4 A in 0.3 s. What is the magnitude of the induced emf?