NEET Electromagnetic Induction — Set 17

Question 1

A solenoid of 450 turns per meter and area 0.018 m² has a current change from 5 A to 2 A in 0.15 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 (450)^2 \times 0.018 \times 1 = 0.00458 \, \text{H} $. $ \varepsilon = L \frac{\Delta I}{\Delta t} = 0.00458 \times \frac{2 - 5}{0.15} = 0.00458 \times (-20) = 0.0916 \, \text{V} \approx 0.092 \, \text{V} $.

Question 2

A coil of 150 turns and area 0.05 m² is in a field that increases from 0 to 0.06 T in 0.3 s. What is the induced emf?

Accepted Answer

$ \Delta \Phi = B A = 0.06 \times 0.05 = 0.003 \, \text{Wb} $. $ \varepsilon = N \frac{\Delta \Phi}{\Delta t} = 150 \times \frac{0.003}{0.3} = 150 \times 0.01 = 1.5 \, \text{V} $.

Question 3

A circular coil of radius 9 cm and 200 turns rotates at 50 rad/s in a 0.03 T field. What is the maximum emf induced?

Accepted Answer

$ A = \pi r^2 = 3.14 \times (0.09)^2 = 0.0254 \, \text{m}^2 $. $ \varepsilon_0 = N B A \omega = 200 \times 0.03 \times 0.0254 \times 50 = 7.62 \, \text{V} $.

NEET Physics: Electromagnetic Induction — Practice Set 17

Q1. A solenoid of 450 turns per meter and area 0.018 m² has a current change from 5 A to 2 A in 0.15 s. What is the self-induced emf? (\( \mu_0 = 4\pi \times 10^{-7} \, \text{H/m} \))

Q2. A coil of 150 turns and area 0.05 m² is in a field that increases from 0 to 0.06 T in 0.3 s. What is the induced emf?

Q3. A circular coil of radius 9 cm and 200 turns rotates at 50 rad/s in a 0.03 T field. What is the maximum emf induced?

Q4. A coil with \( L = 0.4 \, \text{H} \) has its current increased from 0 to 7 A in 0.7 s. What is the energy stored?

Q5. A coil is placed near a current-carrying solenoid. The induced emf in the coil is zero when the solenoid’s current is in what state?

Q6. A coil of 50 turns and area 0.06 m² is in a 0.15 T field that drops to zero in 0.3 s. What is the induced emf?

Q7. A conducting loop is rotated in a uniform magnetic field. The induced emf depends on the rate of change of what physical quantity?

Q8. A coil of 130 turns experiences a magnetic flux change from 0 to 0.06 Wb in 0.12 s. What is the induced emf?

Q9. A coil of 280 turns rotates at 80 rad/s in a 0.06 T field. If the area is 0.01 m², what is the maximum emf?

Q10. A coil of 100 turns and area 0.02 m² is rotated at 50 Hz in a 0.05 T field. What is the maximum emf?