ECAT Physics — Electrostatics
Electrostatics is part of the Physics section of the UET ECAT (30 of the 100 MCQs). It breaks into 4 subtopics, and we hold 35 ECAT-pattern practice MCQs on it, each with a written explanation. Tap a subtopic below to practise just that.
Subtopics (4)
How Electrostatics is tested
Across the 7 ECAT past papers on ParhaiKrlo, Electrostatics accounts for 11 questions. It appears in all 7, about 1.6 questions a paper. The heaviest was ECAT Past Paper 02, with 3 questions, and the most recent is ECAT Past Paper 07, with 2.
| Paper | Questions |
|---|---|
| ECAT Past Paper 07 | 2 |
| ECAT Past Paper 06 | 1 |
| ECAT Past Paper 05 | 1 |
| ECAT Past Paper 04 | 1 |
| ECAT Past Paper 03 | 2 |
| ECAT Past Paper 02 | 3 |
| ECAT Past Paper 01 | 1 |
Electrostatics MCQs from the ECAT past papers
Try each one before opening the answer. Each comes with a short explanation.
- Q1 · ECAT Past Paper 07 · Electrostatics
Two concentric spheres A and B of radii ra > rb enclose a point charge Q at their centre. The total flux through spheres A and B is related as:
- A.Flux through A is greater
- B.Flux through B is greater
- C.Flux through both spheres is equal
- D.Flux through A may be greater or less than B
Show answer
Answer: C. Flux through both spheres is equal — Gauss's law: Φ = Q/ε₀ for any closed surface enclosing Q.
- Q2 · ECAT Past Paper 06 · Electrostatics
You have 20 capacitors, each of 15 F. You need a capacitance of 1 F in a circuit. You can achieve this by connecting:
- A.15 capacitors in parallel
- B.20 capacitors in series
- C.15 capacitors in series
- D.20 capacitors in parallel
Show answer
Answer: C. 15 capacitors in series — n equal capacitors in series give C/n: 15 F/15 = 1 F.
- Q3 · ECAT Past Paper 05 · Electrostatics
Two concentric spheres A and B, of radii ra and rb (ra > rb), enclose a point charge Q at their centre. The total electric flux through spheres A and B is related as:
- A.Flux through A is greater
- B.Flux through both spheres is equal
- C.Flux through A may be greater or less depending on radius
- D.Flux through B is greater
Show answer
Answer: B. Flux through both spheres is equal — Gauss's law: flux = Q/ε₀ for any closed surface enclosing Q, regardless of its size.