Magnetic fields & induction worksheet with answers

Free printable Magnetic fields & induction worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy

A long straight wire carries a current of 2 A. Find the magnetic flux density B at point P, 4 cm from the wire.

I = 2 Ar = 4 cmμ₀ = 4π × 10⁻⁷ T·m/A

B = µT

2.Easy

A straight wire 10 cm long carries 6 A at an angle of 45° to a uniform magnetic field of 0.2 T. Find the magnitude of the force F on the wire.

B = 0.2 TI = 6 AL = 10 cmθ = 45°

F = N

3.Medium

A metal rod 60 cm long slides at 10 m/s along two rails in a uniform field of 0.6 T into the page. The rails are joined by a resistor of 5 Ω; the rod and rails have negligible resistance. Find the power P dissipated in the resistor.

B = 0.6 TL = 60 cmv = 10 m/sR = 5 Ω

P = W

4.Medium

A square loop moves to the right into a region with a uniform magnetic field pointing into 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: into the pageentering the field

1clockwise
2counterclockwise

5.Hard

A coil of 100 turns, 5 cm × 10 cm, rotates at 1800 rpm in a uniform field of 0.1 T about an axis perpendicular to the field. Find the peak emf E₀.

N = 100A = 5 cm × 10 cmB = 0.1 Tn = 1800 rpm

E₀ = V

6.Hard

A long air-core solenoid has 800 turns, a length of 15 cm and a diameter of 4 cm. Find its self-inductance L.

N = 800l = 15 cm⌀ = 4 cmμ₀ = 4π × 10⁻⁷ T·m/A

L = mH

Answer key

1. B = 10 µT
2. F = 0.08485 N
3. P = 2.592 W
4. counterclockwise
5. E₀ = 9.425 V
6. L = 6.738 mH

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