1.Easy
An electron (charge −1.602 × 10⁻¹⁹ C, mass 9.109 × 10⁻³¹ kg) is in a uniform electric field of 3400 N/C. Ignoring gravity, find the magnitude of its acceleration a.
E = 3400 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 −5 µC and −1 µC are 4 cm apart. Find the magnitude of the electric force F between them. Use k = 8.99 × 10⁹ N·m²/C².
q1 = −5 µCq2 = −1 µCr = 4 cm
F = N
3.Medium
Two identical small metal spheres carry charges of −5 µC and +2 µC. They are touched together and then put back 50 cm apart. Find the magnitude of the force F between them now. Use k = 8.99 × 10⁹ N·m²/C².
q1 = −5 µCq2 = +2 µCr = 50 cm
F = N
4.Medium
A charge of +8 µC and a charge of +4 µC are 20 cm apart. Point P lies on the line between them, 10 cm from the first charge. Find the magnitude of the electric field E at P.
q1 = +8 µCq2 = +4 µCr1 = 10 cmr2 = 10 cm
E = N/C
5.Hard
Three positive point charges sit at the corners of a right triangle: q₃ = 5 µC is at the right-angle corner, q₁ = 6 µC is 4 cm from it along one side and q₂ = 2 µC is 4 cm from it along the other side. Find the magnitude of the net electric force F on q₃.
q1 = 6 µCq2 = 2 µCq3 = 5 µCr13 = 4 cmr23 = 4 cm
F = N
6.Hard
Two identical small balls, each of mass 5 g, hang from the same point on insulating threads 100 cm long. They are given equal charges and each thread settles at 10° 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 = 5 gL = 100 cmθ = 10°g = 9.81 m/s²
q = nC
Answer key
- 1. a = 5.98 × 10¹⁴ m/s²
- 2. F = 28.09 N
- 3. F = 0.08091 N
- 4. E = 3.596 × 10⁶ N/C
- 5. F = 177.7 N
- 6. q = 340.6 nC
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