1.Easy
An electron moves at 5 × 10⁵ m/s at an angle of 60° to a uniform magnetic field of 1.5 T. Find the magnitude of the magnetic force F on it.
|q| = 1.602 × 10⁻¹⁹ Cv = 5 × 10⁵ m/sB = 1.5 Tθ = 60°
F = fN
Magnetic fields & induction worksheet with answers
2.Easy
A rectangular loop of 10 cm by 15 cm lies in a uniform magnetic field of 0.2 T. The field lines make an angle of 37° with the plane of the loop. Find the magnetic flux Φ through the loop.
B = 0.2 TA = 10 cm × 15 cm37° to the plane
Φ = mWb
3.Medium
A coil of 25 turns has an area of 40 cm². The coil is turned over (rotated through 180°) in a uniform field of 0.1 T, which is perpendicular to its plane, in 500 ms. Find the average induced emf ε.
N = 25A = 40 cm²B = 0.1 TΔt = 500 ms
ε = mV
4.Medium
A coil of 500 turns has an area of 10 cm². A uniform field perpendicular to the coil rises steadily from 0 T to 0.4 T in 50 ms. Find the average induced emf ε.
N = 500A = 10 cm²B: 0 T → 0.4 TΔt = 50 ms
ε = V
5.Hard
A short coil of 50 turns is wound tightly round the middle of a long solenoid of 1000 turns, length 50 cm and diameter 4 cm. The current in the solenoid changes at 500 A/s. Find the emf ε induced in the short coil.
N1 = 1000N2 = 50l = 50 cm⌀ = 4 cmdi/dt = 500 A/sμ₀ = 4π × 10⁻⁷ T·m/A
ε = mV
6.Hard
A proton starts from rest, is accelerated through a potential difference of 5000 V and then enters a uniform magnetic field of 0.3 T at right angles. Find the radius r of its path in the field.
m = 1.673 × 10⁻²⁷ kg|q| = 1.602 × 10⁻¹⁹ CV = 5000 VB = 0.3 T
r = cm
Answer key
- 1. F = 104.1 fN
- 2. Φ = 1.805 mWb
- 3. ε = 40 mV
- 4. ε = 4 V
- 5. ε = 78.96 mV
- 6. r = 3.406 cm
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