1.Easy
A rectangular loop of 5 cm by 20 cm lies in a uniform magnetic field of 0.25 T. The field makes an angle of 45° with the normal of the loop. Find the magnetic flux Φ through the loop.
B = 0.25 TA = 5 cm × 20 cm45° to the normal
Φ = mWb
Magnetic fields & induction worksheet with answers
2.Easy
A rectangular loop of 8 cm by 20 cm lies in a uniform magnetic field of 0.6 T. The field makes an angle of 53° with the normal of the loop. Find the magnetic flux Φ through the loop.
B = 0.6 TA = 8 cm × 20 cm53° to the normal
Φ = mWb
3.Medium
A coil of 20 turns, area 10 cm² and resistance 5 Ω forms a closed circuit. A uniform field perpendicular to the coil rises steadily from 0.05 T to 0.55 T in 500 ms. Find the average induced current I.
N = 20A = 10 cm²B: 0.05 T → 0.55 TΔt = 500 msR = 5 Ω
I = mA
4.Medium
A coil of 200 turns has an area of 40 cm². The coil is turned over (rotated through 180°) in a uniform field of 0.3 T, which is perpendicular to its plane, in 10 ms. Find the average induced emf ε.
N = 200A = 40 cm²B = 0.3 TΔt = 10 ms
ε = V
5.Hard
A long air-core solenoid has 1500 turns, a length of 15 cm and a diameter of 1 cm. Find its self-inductance L.
N = 1500l = 15 cm⌀ = 1 cmμ₀ = 4π × 10⁻⁷ T·m/A
L = mH
6.Hard
A long air-core solenoid has 200 turns, a length of 10 cm and a diameter of 2 cm. Find its self-inductance L.
N = 200l = 10 cm⌀ = 2 cmμ₀ = 4π × 10⁻⁷ T·m/A
L = µH
Answer key
- 1. Φ = 1.768 mWb
- 2. Φ = 5.777 mWb
- 3. I = 4 mA
- 4. ε = 48 V
- 5. L = 1.48 mH
- 6. L = 157.9 µH
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