1.Easy
Find the magnitude of the electric field E at a distance of 8 cm from a point charge of −5 µC. Use k = 8.99 × 10⁹ N·m²/C².
q = −5 µCr = 8 cm
E = N/C
Coulomb’s law & electric fields worksheet with answers
2.Easy
A proton (charge 1.602 × 10⁻¹⁹ C, mass 1.673 × 10⁻²⁷ kg) is in a uniform electric field of 3500 N/C. Ignoring gravity, find the magnitude of its acceleration a.
E = 3500 N/C|q| = 1.602 × 10⁻¹⁹ Cm = 1.673 × 10⁻²⁷ kg
a = m/s²
3.Medium
A charge of +2 µC and a charge of +6 µC are 60 cm apart. Point P lies on the line between them, 36 cm from the first charge. Find the magnitude of the electric field E at P.
q1 = +2 µCq2 = +6 µCr1 = 36 cmr2 = 24 cm
E = N/C
4.Medium
A charge of +8 µC and a charge of −6 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 = +8 µCq2 = −6 µCr1 = 15 cmr2 = 45 cm
E = N/C
5.Hard
Three positive point charges sit at the corners of a right triangle: q₃ = 6 µC is at the right-angle corner, q₁ = 3 µC is 6 cm from it along one side and q₂ = 6 µC is 3 cm from it along the other side. Find the magnitude of the net electric force F on q₃.
q1 = 3 µCq2 = 6 µCq3 = 6 µCr13 = 6 cmr23 = 3 cm
F = N
6.Hard
Two identical small balls, each of mass 2 g, hang from the same point on insulating threads 50 cm long. They are given equal charges and each thread settles at 12° 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 = 2 gL = 50 cmθ = 12°g = 9.81 m/s²
q = nC
Answer key
- 1. E = 7.023 × 10⁶ N/C
- 2. a = 3.351 × 10¹¹ m/s²
- 3. E = 797724 N/C
- 4. E = 3.463 × 10⁶ N/C
- 5. F = 362.4 N
- 6. q = 141.6 nC
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