1.Easy
A proton (charge 1.602 × 10⁻¹⁹ C, mass 1.673 × 10⁻²⁷ kg) is in a uniform electric field of 2500 N/C. Ignoring gravity, find the magnitude of its acceleration a.
E = 2500 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 25 cm from a point charge of −200 nC. Use k = 8.99 × 10⁹ N·m²/C².
q = −200 nCr = 25 cm
E = N/C
3.Medium
A charge of +10 µC and a charge of −4 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 = +10 µCq2 = −4 µCr1 = 15 cmr2 = 45 cm
E = N/C
4.Medium
A charge of +10 µC and a charge of +4 µC are 20 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 = +10 µCq2 = +4 µCr1 = 15 cmr2 = 5 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 = 3 µC is 6 cm from it along one side and q₂ = 8 µC is 3 cm from it along the other side. Find the magnitude of the net electric force F on q₃.
q1 = 3 µCq2 = 8 µCq3 = 5 µCr13 = 6 cmr23 = 3 cm
F = N
6.Hard
Two identical small balls, each of mass 8 g, hang from the same point on insulating threads 80 cm long. They are given equal charges and each thread settles at 8° 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 = 80 cmθ = 8°g = 9.81 m/s²
q = nC
Answer key
- 1. a = 2.394 × 10¹¹ m/s²
- 2. E = 28768 N/C
- 3. E = 4.173 × 10⁶ N/C
- 4. E = 1.039 × 10⁷ N/C
- 5. F = 401.3 N
- 6. q = 246.6 nC
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