NEET Electromagnetic Induction — Set 5

Question 1

A coil with a ferromagnetic core has higher self-inductance compared to an air-core coil. This is primarily due to what property of the core?

Accepted Answer

The ferromagnetic core increases the magnetic permeability ($ \mu $), enhancing the magnetic flux linkage and thus increasing self-inductance ($ L = \mu n^2 A l $).

Question 2

A loop of 0.5 m × 0.22 m moves out of a 0.7 T field at 1.4 m/s along its longer side. How long does the emf last?

Accepted Answer

Time = distance/velocity, distance = width along motion = 0.22 m. $ t = \frac{0.22}{1.4} = 0.1571 \, \text{s} \approx 0.16 \, \text{s} $.

Question 3

A rectangular loop of sides 20 cm and 8 cm moves out of a 0.45 T field at 1.2 m/s perpendicular to the shorter side. What is the motional emf?

Accepted Answer

$ \varepsilon = B l v $, $ l = 0.2 \, \text{m} $. $ \varepsilon = 0.45 \times 0.2 \times 1.2 = 0.108 \, \text{V} $.

NEET Physics: Electromagnetic Induction — Practice Set 5

Q1. A coil with a ferromagnetic core has higher self-inductance compared to an air-core coil. This is primarily due to what property of the core?

Q2. A loop of 0.5 m × 0.22 m moves out of a 0.7 T field at 1.4 m/s along its longer side. How long does the emf last?

Q3. A rectangular loop of sides 20 cm and 8 cm moves out of a 0.45 T field at 1.2 m/s perpendicular to the shorter side. What is the motional emf?

Q4. A metal disc rotates in a uniform magnetic field perpendicular to its plane. The induced emf between the center and the rim is due to what?

Q5. A flat coil rotates in a uniform magnetic field. The induced emf is zero when the plane of the coil is in which position?

Q6. A coil of 200 turns rotates at 90 rad/s in a 0.04 T field. If the area is 0.015 m², what is the maximum emf?

Q7. A circular loop of radius 9 cm is deformed into a straight wire in a 0.25 T field in 0.4 s. What is the induced emf?

Q8. Two coils are arranged such that their mutual inductance is maximized. What is the most likely orientation of their axes?

Q9. A rod of length 0.3 m moves at 4 m/s in a 0.25 T field perpendicular to its length. What is the induced emf?

Q10. A circular coil of radius 12 cm and 250 turns rotates at 55 rad/s in a 0.025 T field. What is the maximum emf induced?