1.Easy
A proton (charge 1.602 × 10⁻¹⁹ C, mass 1.673 × 10⁻²⁷ kg) is in a uniform electric field of 1800 N/C. Ignoring gravity, find the magnitude of its acceleration a.
E = 1800 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
Two point charges of +10 µC and −10 µC are 6 cm apart. Find the magnitude of the electric force F between them. Use k = 8.99 × 10⁹ N·m²/C².
q1 = +10 µCq2 = −10 µCr = 6 cm
F = N
3.Medium
Charges of +4 µC and +2 µC are 10 cm apart. At what distance x from the +4 µC charge, on the line between them, is the electric field zero?
q1 = +4 µCq2 = +2 µCd = 10 cm
x = cm
4.Medium
A charge of +2 µC and a charge of −1 µC are 50 cm apart. Point P lies on the line between them, 20 cm from the first charge. Find the magnitude of the electric field E at P.
q1 = +2 µCq2 = −1 µCr1 = 20 cmr2 = 30 cm
E = N/C
5.Hard
Three positive point charges sit at the corners of a right triangle: q₃ = 2 µC is at the right-angle corner, q₁ = 8 µC is 5 cm from it along one side and q₂ = 4 µC is 6 cm from it along the other side. Find the magnitude of the net electric force F on q₃.
q1 = 8 µCq2 = 4 µCq3 = 2 µCr13 = 5 cmr23 = 6 cm
F = N
6.Hard
Two identical small balls, each of mass 8 g, hang from the same point on insulating threads 30 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 = 30 cmθ = 8°g = 9.81 m/s²
q = nC
Answer key
- 1. a = 1.724 × 10¹¹ m/s²
- 2. F = 249.7 N
- 3. x = 5.858 cm
- 4. E = 549389 N/C
- 5. F = 60.91 N
- 6. q = 92.49 nC
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