1.Easy
A rectangular loop of 15 cm by 15 cm lies in a uniform magnetic field of 0.1 T. The field lines make an angle of 30° with the plane of the loop. Find the magnetic flux Φ through the loop.
B = 0.1 TA = 15 cm × 15 cm30° to the plane
Φ = mWb
Magnetic fields & induction worksheet with answers
2.Easy
A long straight wire carries a current of 25 A. Find the magnetic flux density B at point P, 15 cm from the wire.
I = 25 Ar = 15 cmμ₀ = 4π × 10⁻⁷ T·m/A
B = µT
3.Medium
A square loop moves to the right into a region with a uniform magnetic field pointing out of the page. Click the direction of the induced current in the loop as seen in the drawing, while the loop is entering the field.
B: out of the pageentering the field
- 1clockwise
- 2counterclockwise
4.Medium
A coil of 10 turns, area 50 cm² and resistance 2 Ω forms a closed circuit. A uniform field perpendicular to the coil rises steadily from 0.2 T to 0.7 T in 100 ms. Find the average induced current I.
N = 10A = 50 cm²B: 0.2 T → 0.7 TΔt = 100 msR = 2 Ω
I = mA
5.Hard
A long air-core solenoid has 300 turns, a length of 15 cm and a diameter of 1 cm. Find its self-inductance L.
N = 300l = 15 cm⌀ = 1 cmμ₀ = 4π × 10⁻⁷ T·m/A
L = µH
6.Hard
An alpha particle starts from rest, is accelerated through a potential difference of 2500 V and then enters a uniform magnetic field of 0.5 T at right angles. Find the radius r of its path in the field.
m = 6.645 × 10⁻²⁷ kg|q| = 3.204 × 10⁻¹⁹ CV = 2500 VB = 0.5 T
r = cm
Answer key
- 1. Φ = 1.125 mWb
- 2. B = 33.33 µT
- 3. clockwise
- 4. I = 125 mA
- 5. L = 59.22 µH
- 6. r = 2.037 cm
Full step-by-step solutions: practise this topic on examproblems.com.