1.Easy
Two point charges of −3 µC and +4 µC are 12 cm apart. Find the magnitude of the electric force F between them. Use k = 8.99 × 10⁹ N·m²/C².
q1 = −3 µCq2 = +4 µCr = 12 cm
F = N
Coulomb’s law & electric fields worksheet with answers
2.Easy
Two point charges of −10 µC and +1 µC are 10 cm apart. Find the magnitude of the electric force F between them. Use k = 8.99 × 10⁹ N·m²/C².
q1 = −10 µCq2 = +1 µCr = 10 cm
F = N
3.Medium
Two identical small metal spheres carry charges of +4 µC and −1 µC. They are touched together and then put back 25 cm apart. Find the magnitude of the force F between them now. Use k = 8.99 × 10⁹ N·m²/C².
q1 = +4 µCq2 = −1 µCr = 25 cm
F = N
4.Medium
A charge of +6 µC and a charge of −6 µC are 10 cm apart. Point P lies on the line between them, 6 cm from the first charge. Find the magnitude of the electric field E at P.
q1 = +6 µCq2 = −6 µCr1 = 6 cmr2 = 4 cm
E = N/C
5.Hard
An electron enters the uniform field between two parallel plates moving parallel to them at 3.5 × 10⁷ m/s. The plates are 10 cm long and the field between them is 4400 N/C. Electron charge 1.602 × 10⁻¹⁹ C, mass 9.109 × 10⁻³¹ kg; ignore gravity. How far y is it deflected sideways when it leaves the plates? Give the answer in mm.
v₀ = 3.5 × 10⁷ m/sL = 10 cmE = 4400 N/Ce = 1.602 × 10⁻¹⁹ Cme = 9.109 × 10⁻³¹ kg
y = mm
6.Hard
Two identical small balls, each of mass 8 g, hang from the same point on insulating threads 60 cm long. They are given equal charges and each thread settles at 5° from the vertical. Use g = 9.81 m/s². Find the charge q on each ball in nC. Use k = 8.99 × 10⁹ N·m²/C².
m = 8 gL = 60 cmθ = 5°g = 9.81 m/s²
q = nC
Answer key
- 1. F = 7.492 N
- 2. F = 8.99 N
- 3. F = 0.3236 N
- 4. E = 4.87 × 10⁷ N/C
- 5. y = 3.158 mm
- 6. q = 91.4 nC
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