Sankalp NEET Full Test-5 Question-4 Solution

Question: 4: A cell of emf 4 V and internal resistance 0.5 \Omega is connected to a 7.5 \Omega external resistance. The terminal potential difference of the cell is :-

(1) 3.75 V

(2) 4.25 V

(3) 4 V

(4) 0.375 V

Answer: Option (1)

Explanation:

When a cell of emf E and internal resistance r is connected to an external resistance R, the current in the circuit is given by

I=\frac{E}{R+r}

Substituting the given values,

I=\frac{4}{7.5+0.5}=\frac{4}{8}=0.5\ \text{A}

The terminal potential difference V across the cell is equal to the potential difference across the external resistance, given by

V=IR

Substituting the values,

V=0.5 \times 7.5=3.75\ \text{V}

Hence, the terminal potential difference of the cell is 3.75 V.