1.Easy
An electron (charge −1.602 × 10⁻¹⁹ C, mass 9.109 × 10⁻³¹ kg) is in a uniform electric field of 900 N/C. Ignoring gravity, find the magnitude of its acceleration a.
E = 900 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
Find the magnitude of the electric field E at a distance of 10 cm from a point charge of +20 nC. Use k = 8.99 × 10⁹ N·m²/C².
q = +20 nCr = 10 cm
E = N/C
3.Medium
A charge of +1 µC and a charge of +4 µC are 10 cm apart. Point P lies on the line between them, 6 cm from the first charge. Find the magnitude of the electric field E at P.
q1 = +1 µCq2 = +4 µCr1 = 6 cmr2 = 4 cm
E = N/C
4.Medium
Charges of +1 µC and +10 µC are 80 cm apart. At what distance x from the +1 µC charge, on the line between them, is the electric field zero?
q1 = +1 µCq2 = +10 µCd = 80 cm
x = cm
5.Hard
An electron enters the uniform field between two parallel plates moving parallel to them at 2 × 10⁷ m/s. The plates are 3 cm long and the field between them is 3600 N/C. Electron charge 1.602 × 10⁻¹⁹ C, mass 9.109 × 10⁻³¹ kg; ignore gravity. How far y is it deflected sideways when it leaves the plates? Give the answer in mm.
v₀ = 2 × 10⁷ m/sL = 3 cmE = 3600 N/Ce = 1.602 × 10⁻¹⁹ Cme = 9.109 × 10⁻³¹ kg
y = mm
6.Hard
Three positive point charges sit at the corners of a right triangle: q₃ = 1 µC is at the right-angle corner, q₁ = 6 µC is 4 cm from it along one side and q₂ = 5 µC is 10 cm from it along the other side. Find the magnitude of the net electric force F on q₃.
q1 = 6 µCq2 = 5 µCq3 = 1 µCr13 = 4 cmr23 = 10 cm
F = N
Answer key
- 1. a = 1.583 × 10¹⁴ m/s²
- 2. E = 17980 N/C
- 3. E = 1.998 × 10⁷ N/C
- 4. x = 19.22 cm
- 5. y = 0.7123 mm
- 6. F = 34.01 N
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