NUST NET Physics chapter 5: Physics · Electricity MCQs with answers
By Team Megalecture · Updated 4 Nov 2026
30 exam-style questions on Physics · Electricity, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.
Try each one, then open the answer. These ten stay the same; the test draws new ones every time.
1. Three identical cells, each of EMF 2.0 V and internal resistance 0.50 Ω, are connected in series to a 4.5 Ω resistor. The current in the resistor is
A
1.3 A
B
1.0 A
C
0.33 A
D
1.2 A
Show answer
Answer: B. In series the EMFs and the internal resistances both add: E = 6.0 V and r = 1.5 Ω. I = E/(R + r) = 6.0/6.0 = 1.0 A. Ignoring the internal resistances gives 1.3 A, and counting only one of them gives 1.2 A.
2. Two point charges of 1.0 μC each are 3.0 cm apart in air. Taking k = 9 × 109 N m2 C−2, the force between them is
A
0.30 N
B
10 N
C
0.10 N
D
1.0 × 10−3 N
Show answer
Answer: B. F = kq1q2/r2 = 9 × 109 × 10−12/(9 × 10−4) = 10 N. Not squaring r gives 0.30 N, and leaving r in centimetres gives 1.0 × 10−3 N.
3. The SI unit of resistivity is
A
Ω m−1
B
Ω
C
Ω m
D
Ω m2
Show answer
Answer: C. ρ = RA/L has the unit Ω × m2 ÷ m = Ω m.
4. Four wires meet at a junction. Currents of 5 A and 3 A flow towards the junction and 2 A flows away from it in the third wire. The current in the fourth wire is
A
6 A towards the junction
B
10 A away from the junction
C
6 A away from the junction
D
zero
Show answer
Answer: C. By Kirchhoff's first rule, total in = total out: 5 + 3 = 2 + I, so I = 6 A flowing away. Adding all three currents gives the wrong 10 A.
5. The resistance of a pure semiconductor such as silicon falls as its temperature rises, because
A
its atoms vibrate less
B
it expands, so its cross-section grows
C
its free electrons collide less often with the atoms
D
more electrons gain enough energy to become free charge carriers
Show answer
Answer: D. Heating breaks more covalent bonds and frees more electrons (and holes) to carry current, so the resistance falls: a negative temperature coefficient. In a metal the number of carriers is fixed, and stronger atomic vibration raises the resistance.
6. Taking k = 9 × 109 N m2 C−2, the electric potential at a distance of 0.30 m from a point charge of +2.0 nC is
A
200 V
B
18 V
C
60 V
D
5.4 V
Show answer
Answer: C. V = kq/r = 9 × 109 × 2.0 × 10−9/0.30 = 18/0.30 = 60 V. 200 V divides by r2, which gives the field strength in N C−1, not the potential.
7. A uniform wire of resistance R is drawn out so that its length doubles, its volume staying the same. Its new resistance is
A
4R
B
2R
C
8R
D
R/4
Show answer
Answer: A. Length doubles and, at constant volume, the cross-sectional area halves, so R = ρL/A becomes 2/(1/2) = 4 times larger. Ignoring the change in area gives 2R.
8. Two point charges exert a force F on each other. One charge is doubled and the distance between them is tripled. The new force is
A
2F/3
B
4F/9
C
9F/2
D
2F/9
Show answer
Answer: D. F ∝ q1q2/r2, so the force becomes F × 2/32 = 2F/9. Forgetting to square the distance gives 2F/3.
9. A coil has a resistance of 10.0 Ω at 0 °C and 12.0 Ω at 100 °C. The temperature coefficient of resistance of its material is
A
2.0 × 10−3 K−1
B
1.7 × 10−3 K−1
C
2.0 × 10−2 K−1
D
0.20 K−1
Show answer
Answer: A. α = (Rt − R0)/(R0t) = (12.0 − 10.0)/(10.0 × 100) = 2.0 × 10−3 K−1. Dividing by 12.0 Ω instead of R0 gives 1.7 × 10−3 K−1.
10. A battery of EMF 12 V and internal resistance 2.0 Ω is connected to a variable external resistor. The greatest power that can be delivered to the resistor is
A
72 W
B
36 W
C
9 W
D
18 W
Show answer
Answer: D. The power in the load is greatest when R = r = 2.0 Ω. Then I = 12/4.0 = 3.0 A and P = I2R = 9 × 2.0 = 18 W. 36 W is the total power, including the 18 W wasted inside the battery.
Chapter test. Ten questions from Physics · Electricity, drawn fresh each time, about ten minutes.
Practice mode. The right answer and the explanation after every question, with no clock. Exam mode keeps the marks until the end and runs a timer.
Hints. One tap for a nudge, a second to remove two wrong options.
My mistakes. Every question you get wrong is kept, and leaves the list once you get it right.
Physics · Electricity: questions students ask
How many Physics · Electricity MCQs are there?
30, each with the answer and a short explanation, across 2 topics: Electrostatics, Current electricity. Every chapter test draws ten of them, so you can take it many times.
Is the NUST NET Physics chapter 5 test free?
Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.
How is the chapter test marked?
The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.
Can I read the explanations in Urdu?
Yes. In practice mode and on your results you can switch the explanations to Urdu.
