A battery of emf 10 V and internal resistance 3 is connected to an external resistor. If the current in the circuit is 0.5 A, then the voltage drop across the external resistor will be
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 8.5 V
Given:
EMF of battery: $E = 10~\text{V}$
Internal resistance: $r = 3~\Omega$
Current: $I = 0.5~\text{A}$
Voltage across external resistor:
$V_\text{ext} = E - I r$
$V_\text{ext} = 10 - (0.5 \cdot 3) = 10 - 1.5 = 8.5~\text{V}$
Answer: $V_\text{ext} = 8.5~\text{V}$