1.Easy
A proton (charge 1.602 × 10⁻¹⁹ C, mass 1.673 × 10⁻²⁷ kg) is in a uniform electric field of 1700 N/C. Ignoring gravity, find the magnitude of its acceleration a.
E = 1700 N/C|q| = 1.602 × 10⁻¹⁹ Cm = 1.673 × 10⁻²⁷ kg
a = m/s²
Coulomb’s law & electric fields worksheet with answers
2.Easy
Find the magnitude of the electric field E at a distance of 2 cm from a point charge of −2 µC. Use k = 8.99 × 10⁹ N·m²/C².
q = −2 µCr = 2 cm
E = N/C
3.Medium
A charge of +8 µC and a charge of −1 µC are 20 cm apart. Point P lies on the line between them, 5 cm from the first charge. Find the magnitude of the electric field E at P.
q1 = +8 µCq2 = −1 µCr1 = 5 cmr2 = 15 cm
E = N/C
4.Medium
Two identical small metal spheres carry charges of +6 µC and −5 µC. They are touched together and then put back 40 cm apart. Find the magnitude of the force F between them now. Use k = 8.99 × 10⁹ N·m²/C².
q1 = +6 µCq2 = −5 µCr = 40 cm
F = N
5.Hard
Two identical small balls, each of mass 10 g, hang from the same point on insulating threads 50 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 = 10 gL = 50 cmθ = 10°g = 9.81 m/s²
q = nC
6.Hard
Three positive point charges sit at the corners of a right triangle: q₃ = 6 µC is at the right-angle corner, q₁ = 4 µC is 4 cm from it along one side and q₂ = 5 µC is 8 cm from it along the other side. Find the magnitude of the net electric force F on q₃.
q1 = 4 µCq2 = 5 µCq3 = 6 µCr13 = 4 cmr23 = 8 cm
F = N
Answer key
- 1. a = 1.628 × 10¹¹ m/s²
- 2. E = 4.495 × 10⁷ N/C
- 3. E = 2.917 × 10⁷ N/C
- 4. F = 0.01405 N
- 5. q = 240.9 nC
- 6. F = 141.3 N
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