Coulomb’s law & electric fields worksheet with answers

Free printable Coulomb’s law & electric fields worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

New worksheetPractise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy
+ + + + + +− − − − − −e⁻E = 4300 N/C

An electron (charge −1.602 × 10⁻¹⁹ C, mass 9.109 × 10⁻³¹ kg) is in a uniform electric field of 4300 N/C. Ignoring gravity, find the magnitude of its acceleration a.

E = 4300 N/C|q| = 1.602 × 10⁻¹⁹ Cm = 9.109 × 10⁻³¹ kg
a = m/s²
2.Easy
+ + + + + +− − − − − −e⁻E = 2700 N/C

An electron (charge −1.602 × 10⁻¹⁹ C, mass 9.109 × 10⁻³¹ kg) is in a uniform electric field of 2700 N/C. Ignoring gravity, find the magnitude of its acceleration a.

E = 2700 N/C|q| = 1.602 × 10⁻¹⁹ Cm = 9.109 × 10⁻³¹ kg
a = m/s²
3.Medium
++8 µC++3 µC++2 µC18 cm + 12 cm

Three point charges lie on a straight line: +8 µC on the left, +2 µC on the right 30 cm away, and +3 µC between them, 18 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 = +8 µCqR = +2 µCqM = +3 µCrL = 18 cmrR = 12 cm
F = N
4.Medium
++8 µC−−5 µCP10 cm

A charge of +8 µC and a charge of −5 µC are 10 cm apart. Point P lies on the line between them, 5 cm from the first charge. Find the magnitude of the electric field E at P.

q1 = +8 µCq2 = −5 µCr1 = 5 cmr2 = 5 cm
E = N/C
5.Hard
10 cm6 cm+q1​ = +3 µC+q3​ = +4 µC+q2​ = +6 µC

Three positive point charges sit at the corners of a right triangle: q₃ = 4 µC is at the right-angle corner, q₁ = 3 µC is 10 cm from it along one side and q₂ = 6 µC is 6 cm from it along the other side. Find the magnitude of the net electric force F on q₃.

q1 = 3 µCq2 = 6 µCq3 = 4 µCr13 = 10 cmr23 = 6 cm
F = N
6.Hard
5 cm3 cm+q1​ = +3 µC+q3​ = +2 µC+q2​ = +1 µC

Three positive point charges sit at the corners of a right triangle: q₃ = 2 µC is at the right-angle corner, q₁ = 3 µC is 5 cm from it along one side and q₂ = 1 µC is 3 cm from it along the other side. Find the magnitude of the net electric force F on q₃.

q1 = 3 µCq2 = 1 µCq3 = 2 µCr13 = 5 cmr23 = 3 cm
F = N

Answer key

  1. 1. a = 7.562 × 10¹⁴ m/s²
  2. 2. a = 4.748 × 10¹⁴ m/s²
  3. 3. F = 2.913 N
  4. 4. E = 4.675 × 10⁷ N/C
  5. 5. F = 60.9 N
  6. 6. F = 29.4 N

Full step-by-step solutions: practise this topic on examproblems.com.