Board-style MCQs and past-paper numericals in the BIEK / Sindh Board pattern. Tap an option to check yourself instantly. Solved questions are at the bottom.
Multiple-choice questions
Solved numericals (past papers)
Current from charge and time
A charge of 120 C flows through a wire in 1 minute. Find the current.
I = Q / t = 120 / 60
I = 2 A
Ohm's law — finding resistance
A potential difference of 12 V drives a current of 0.5 A through a resistor. Find R.
R = V / I = 12 / 0.5
R = 24 Ω
Resistance from resistivity
A copper wire is 2 m long with a cross-section of 1 mm² (ρ = 1.7×10⁻⁸ Ω·m). Find R.
A = 1 mm² = 1×10⁻⁶ m²
R = ρL / A = (1.7×10⁻⁸ × 2) / (1×10⁻⁶)
R = (3.4×10⁻⁸) / (10⁻⁶) = 3.4 × 10⁻² Ω = 0.034 Ω
Resistors in series and parallel
Two resistors 6 Ω and 3 Ω.
In series: R = 6 + 3 = 9 Ω
In parallel: 1/R = 1/6 + 1/3 = 1/6 + 2/6 = 3/6, so R = 2 Ω
EMF and internal resistance
A cell of EMF 1.5 V and internal resistance 0.5 Ω is connected to a 2.5 Ω external resistor. Find the current.
I = E / (R + r) = 1.5 / (2.5 + 0.5)
I = 1.5 / 3.0 = 0.5 A; terminal V = IR = 0.5 × 2.5 = 1.25 V
Electrical power
A heater draws 5 A from a 220 V supply. Find the power consumed.
P = VI = 220 × 5
P = 1100 W = 1.1 kW