1.Easy
An electron (charge −1.602 × 10⁻¹⁹ C, mass 9.109 × 10⁻³¹ kg) is in a uniform electric field of 900 N/C. Ignoring gravity, find the magnitude of its acceleration a.
E = 900 N/C|q| = 1.602 × 10⁻¹⁹ Cm = 9.109 × 10⁻³¹ kg
a = m/s²
Coulomb’s law & electric fields worksheet with answers
2.Easy
Two point charges of −10 µC and −3 µC are 5 cm apart. Find the magnitude of the electric force F between them. Use k = 8.99 × 10⁹ N·m²/C².
q1 = −10 µCq2 = −3 µCr = 5 cm
F = N
3.Medium
Two identical small metal spheres carry charges of +10 µC and +8 µC. They are touched together and then put back 10 cm apart. Find the magnitude of the force F between them now. Use k = 8.99 × 10⁹ N·m²/C².
q1 = +10 µCq2 = +8 µCr = 10 cm
F = N
4.Medium
Three point charges lie on a straight line: +6 µC on the left, +2 µC on the right 20 cm away, and +1 µC between them, 8 cm from the left charge. Find the magnitude of the net electric force F on the middle charge. Use k = 8.99 × 10⁹ N·m²/C².
qL = +6 µCqR = +2 µCqM = +1 µCrL = 8 cmrR = 12 cm
F = N
5.Hard
Three positive point charges sit at the corners of a right triangle: q₃ = 2 µC is at the right-angle corner, q₁ = 10 µC is 6 cm from it along one side and q₂ = 6 µC is 8 cm from it along the other side. Find the magnitude of the net electric force F on q₃.
q1 = 10 µCq2 = 6 µCq3 = 2 µCr13 = 6 cmr23 = 8 cm
F = N
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 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 = 8 gL = 60 cmθ = 20°g = 9.81 m/s²
q = nC
Answer key
- 1. a = 1.583 × 10¹⁴ m/s²
- 2. F = 107.9 N
- 3. F = 72.82 N
- 4. F = 7.18 N
- 5. F = 52.71 N
- 6. q = 731.6 nC
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