1.Easy
Two point charges of +1 µC and −4 µC are 6 cm apart. Find the magnitude of the electric force F between them. Use k = 8.99 × 10⁹ N·m²/C².
q1 = +1 µCq2 = −4 µCr = 6 cm
F = N
Coulomb’s law & electric fields worksheet with answers
2.Easy
Two point charges of −6 µC and +5 µC are 6 cm apart. Find the magnitude of the electric force F between them. Use k = 8.99 × 10⁹ N·m²/C².
q1 = −6 µCq2 = +5 µCr = 6 cm
F = N
3.Medium
A charge of +4 µC and a charge of −3 µC are 30 cm apart. Point P lies on the line between them, 12 cm from the first charge. Find the magnitude of the electric field E at P.
q1 = +4 µCq2 = −3 µCr1 = 12 cmr2 = 18 cm
E = N/C
4.Medium
A charge of +3 µC and a charge of −1 µC are 60 cm apart. Point P lies on the line between them, 15 cm from the first charge. Find the magnitude of the electric field E at P.
q1 = +3 µCq2 = −1 µCr1 = 15 cmr2 = 45 cm
E = N/C
5.Hard
Three positive point charges sit at the corners of a right triangle: q₃ = 4 µC is at the right-angle corner, q₁ = 3 µC is 4 cm from it along one side and q₂ = 10 µC is 8 cm from it along the other side. Find the magnitude of the net electric force F on q₃.
q1 = 3 µCq2 = 10 µCq3 = 4 µCr13 = 4 cmr23 = 8 cm
F = N
6.Hard
Two identical small balls, each of mass 1 g, hang from the same point on insulating threads 40 cm long. They are given equal charges and each thread settles at 20° 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 = 1 gL = 40 cmθ = 20°g = 9.81 m/s²
q = nC
Answer key
- 1. F = 9.989 N
- 2. F = 74.92 N
- 3. E = 3.33 × 10⁶ N/C
- 4. E = 1.243 × 10⁶ N/C
- 5. F = 87.77 N
- 6. q = 172.4 nC
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