Practise 40 real Federal Board questions on Current Electricity from 2023 to 2026. See the answer and explanation as soon as you answer.
Current Electricity is one of the 14 main chapters in our Federal Board FSC Physics question bank (11th and 12th class), and about 8% of its real questions come from it. Tayyari Karo has 40 real questions on this chapter from 2023 to 2026; 11 are multiple choice and marked instantly, and the rest are short and long questions with a model answer. By difficulty: 26 medium, 13 easy, 1 hard.
Work through the questions below, then open the explanation for each one. Redo the ones you missed a few days later.
These are real past-paper questions. Think of your answer first, then open the explanation.
A potentiometer is used to compare:
Answer: C. Potential difference
A potentiometer compares potential differences (emfs) using a null-deflection method, without drawing current from the source being measured.
In order to achieve high accuracy, the slide wire of a potentiometer should be:
Answer: A. As long as possible
A longer wire gives a smaller potential gradient (V per unit length), allowing the balance point to be located more precisely — increasing accuracy.
A 10Ω resistor is connected across the terminals of a 10V battery. The power dissipation of the resistor is:
Answer: C. 10 W
P = V²/R = 10²/10 = 10 W.
The best instrument for the accurate measurement of emf of a cell is:
Answer: A. Potentiometer
A potentiometer measures emf accurately because at balance it draws no current from the cell, unlike a voltmeter which always draws some current.
A 60 watt bulb operates at 50% efficiency; the energy dissipated (as heat) in 10 seconds is:
Answer: D. 300 J
Total energy input = Pt = 60×10 = 600 J. At 50% efficiency, half is useful output and half (300 J) is dissipated as heat.
Three resistors each of 2 Ohm are connected to form a triangle. The resistance on any corner is:
Answer: B. 4/3 Ohm
Between any two corners of the triangle, one 2Ω side is in parallel with the other two 2Ω sides in series (2+2=4Ω): R = (2×4)/(2+4) = 8/6 = 4/3 Ω.
Calculate the resistance of a wire 10 m long that has a diameter of 3 mm and resistivity of 2.63 × 10⁻² Ω·m.
R = ρL/A, where A = πd²/4
A = π(3×10⁻³)²/4 = π(9×10⁻⁶)/4 ≈ 7.07×10⁻⁶ m²
R = (2.63×10⁻²)(10)/(7.07×10⁻⁶) = 0.263/(7.07×10⁻⁶)
R ≈ 3.72 × 10⁴ Ω
State Ohm's law. Derive its mathematical form and give its limitations.
Ohm's law: At constant temperature, the current I flowing through a conductor is directly proportional to the potential difference V applied across its ends: I ∝ V, so V = IR, where R (resistance) is the constant of proportionality.
Derivation: Since I ∝ V, we can write V = IR, where R = V/I is a constant for a given conductor at a given (constant) temperature.
Limitations:
1. Ohm's law holds only if the temperature (and other physical conditions) of the conductor remain constant.
2. It does not apply to non-ohmic devices, such as diodes, transistors, and thermistors, whose V-I graph is not a straight line through the origin.
3. …
The full model answer is in the app.
| Session | Questions |
|---|---|
| 2026 Annual | 4 |
| 2025 1st Annual | 11 |
| 2025 2nd Annual | 11 |
| 2024 Annual | 9 |
| 2023 Annual | 5 |
40 real Federal Board (FBISE) Physics questions on Current Electricity from 2023 to 2026, for 11th and 12th class. Each one shows the session it came from.
No. We could not find an official FBISE marking scheme for these papers, so the answers and explanations are written by Tayyari Karo for practice. Check anything important with your teacher or textbook.
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