NEET Electromagnetic Induction — Set 11

Question 1

A rod rotates at 16 rad/s in a 0.6 T field. If the length from the axis to the tip is 0.5 m, what is the emf induced?

Accepted Answer

$ \varepsilon = \frac{1}{2} B \omega R^2 $. $ \varepsilon = \frac{1}{2} \times 0.6 \times 16 \times (0.5)^2 = 1.2 \, \text{V} $.

Question 2

A coil of 140 turns and area 0.02 m² is rotated at 25 Hz in a 0.07 T field. What is the maximum emf?

Accepted Answer

$ \omega = 2\pi v = 2\pi \times 25 = 50\pi \, \text{rad/s} $. $ \varepsilon_0 = N B A \omega = 140 \times 0.07 \times 0.02 \times 50\pi = 30.79 \, \text{V} \approx 30.8 \, \text{V} $.

Question 3

A magnet is oscillated near a coil. The induced emf in the coil alternates because of what characteristic of the magnet’s motion?

Accepted Answer

The oscillatory motion causes the magnetic flux to alternately increase and decrease, inducing an alternating emf as the flux change direction reverses.

NEET Physics: Electromagnetic Induction — Practice Set 11

Q1. A rod rotates at 16 rad/s in a 0.6 T field. If the length from the axis to the tip is 0.5 m, what is the emf induced?

Q2. A coil of 140 turns and area 0.02 m² is rotated at 25 Hz in a 0.07 T field. What is the maximum emf?

Q3. A magnet is oscillated near a coil. The induced emf in the coil alternates because of what characteristic of the magnet’s motion?

Q4. A rod rotates at 18 rad/s in a 0.4 T field. If the length from the axis to the tip is 0.7 m, what is the emf induced?

Q5. A solenoid of 500 turns per meter and area 0.02 m² has a current drop from 6 A to 3 A in 0.25 s. What is the self-induced emf? (\( \mu_0 = 4\pi \times 10^{-7} \, \text{H/m} \))

Q6. A rectangular loop of sides 28 cm and 14 cm moves out of a 0.7 T field at 1.2 m/s perpendicular to the longer side. What is the motional emf?

Q7. A coil of 250 turns rotates at 80 rad/s in a 0.04 T field. If the area is 0.015 m², what is the maximum emf?

Q8. A loop of 0.4 m × 0.18 m moves out of a 0.5 T field at 1.8 m/s along its longer side. How long does the emf last?

Q9. A flat coil is placed in a magnetic field that decreases with time. The direction of the induced current is such that it produces a magnetic field in which direction?

Q10. A coil of 180 turns and area 0.09 m² is in a field that decreases from 0.11 T to 0 in 0.6 s. What is the induced emf?