1.Easy
A proton (charge 1.602 × 10⁻¹⁹ C, mass 1.673 × 10⁻²⁷ kg) is in a uniform electric field of 1500 N/C. Ignoring gravity, find the magnitude of its acceleration a.
E = 1500 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
A proton (charge 1.602 × 10⁻¹⁹ C, mass 1.673 × 10⁻²⁷ kg) is in a uniform electric field of 3900 N/C. Ignoring gravity, find the magnitude of its acceleration a.
E = 3900 N/C|q| = 1.602 × 10⁻¹⁹ Cm = 1.673 × 10⁻²⁷ kg
a = m/s²
3.Medium
Three point charges lie on a straight line: +4 µC on the left, +1 µC on the right 30 cm away, and +1 µC between them, 12 cm from the left charge. Find the magnitude of the net electric force F on the middle charge. Use k = 8.99 × 10⁹ N·m²/C².
qL = +4 µCqR = +1 µCqM = +1 µCrL = 12 cmrR = 18 cm
F = N
4.Medium
Charges of +10 µC and +1 µC are 20 cm apart. At what distance x from the +10 µC charge, on the line between them, is the electric field zero?
q1 = +10 µCq2 = +1 µCd = 20 cm
x = cm
5.Hard
An electron enters the uniform field between two parallel plates moving parallel to them at 1.5 × 10⁷ m/s. The plates are 5 cm long and the field between them is 600 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 = 1.5 × 10⁷ m/sL = 5 cmE = 600 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 = 8 µC is at the right-angle corner, q₁ = 6 µC is 8 cm from it along one side and q₂ = 10 µC is 8 cm from it along the other side. Find the magnitude of the net electric force F on q₃.
q1 = 6 µCq2 = 10 µCq3 = 8 µCr13 = 8 cmr23 = 8 cm
F = N
Answer key
- 1. a = 1.436 × 10¹¹ m/s²
- 2. a = 3.734 × 10¹¹ m/s²
- 3. F = 2.22 N
- 4. x = 15.19 cm
- 5. y = 0.5862 mm
- 6. F = 131.1 N
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