1.Easy
A rectangular loop of 12 cm by 30 cm lies in a uniform magnetic field of 1.2 T. The field makes an angle of 45° with the normal of the loop. Find the magnetic flux Φ through the loop.
B = 1.2 TA = 12 cm × 30 cm45° to the normal
Φ = mWb
Magnetic fields & induction worksheet with answers
2.Easy
A proton moves at 8 × 10⁶ m/s at an angle of 60° to a uniform magnetic field of 0.8 T. Find the magnitude of the magnetic force F on it.
|q| = 1.602 × 10⁻¹⁹ Cv = 8 × 10⁶ m/sB = 0.8 Tθ = 60°
F = fN
3.Medium
Two long parallel wires 2 cm apart carry currents of 15 A and 25 A in opposite directions. Find the force per metre of length F/L between them.
I1 = 15 AI2 = 25 Ad = 2 cmμ₀ = 4π × 10⁻⁷ T·m/A
F/L = µN/m
4.Medium
A circular loop lies in a uniform magnetic field pointing into the page. The field strength is increasing. Click the direction of the induced current in the loop as seen in the drawing.
B: into the pagedB/dt > 0
- 1clockwise
- 2counterclockwise
5.Hard
A deuteron passes undeflected through a velocity selector with crossed fields E = 5 × 10⁵ V/m and B₁ = 0.2 T. It then enters a second region with only a magnetic field B₂ = 0.2 T, at right angles. Find the radius r of its path there.
E = 5 × 10⁵ V/mB1 = 0.2 TB2 = 0.2 Tm = 3.344 × 10⁻²⁷ kg|q| = 1.602 × 10⁻¹⁹ C
r = cm
6.Hard
An alpha particle starts from rest, is accelerated through a potential difference of 10000 V and then enters a uniform magnetic field of 0.4 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 = 10000 VB = 0.4 T
r = cm
Answer key
- 1. Φ = 30.55 mWb
- 2. F = 887.9 fN
- 3. F/L = 3750 µN/m
- 4. counterclockwise
- 5. r = 26.09 cm
- 6. r = 5.092 cm
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