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 solenoid 25 cm long has 1200 turns. Which current I gives a magnetic flux density of 3.016 mT inside it?

N = 1200L = 25 cmB = 3.016 mTμ₀ = 4π × 10⁻⁷ T·m/A

I = A

2.Easy

A long straight wire carries 8 A. At what distance r from the wire is the magnetic flux density 10.67 µT?

I = 8 AB = 10.67 µTμ₀ = 4π × 10⁻⁷ T·m/A

r = cm

3.Medium

A coil of 100 turns, area 40 cm² and resistance 8 Ω forms a closed circuit. A uniform field perpendicular to the coil rises steadily from 0.2 T to 0.7 T in 200 ms. Find the average induced current I.

N = 100A = 40 cm²B: 0.2 T → 0.7 TΔt = 200 msR = 8 Ω

I = mA

4.Medium

A wire carries a current to the right through a uniform magnetic field pointing into the page. Click the direction of the magnetic force on the wire.

I: to the rightB: into the page

1up the page
2to the right
3down the page
4to the left

5.Hard

A long air-core solenoid has 200 turns, a length of 25 cm and a diameter of 2 cm. Find its self-inductance L.

N = 200l = 25 cm⌀ = 2 cmμ₀ = 4π × 10⁻⁷ T·m/A

L = µH

6.Hard

A coil of 200 turns, 10 cm × 5 cm, rotates at 600 rpm in a uniform field of 0.05 T about an axis perpendicular to the field. Find the peak emf E₀.

N = 200A = 10 cm × 5 cmB = 0.05 Tn = 600 rpm

E₀ = V

Answer key

1. I = 0.5 A
2. r = 15 cm
3. I = 125 mA
4. up the page
5. L = 63.17 µH
6. E₀ = 3.142 V

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