A cell of e.m.f. 1.5V is connected in series with a resistor of resistance 3.0\(\Omega\). A voltmeter connected across the cell registers 0.9V. Calculate th...

A cell of e.m.f. 1.5V is connected in series with a resistor of resistance 3.0\(\Omega\). A voltmeter connected across the cell registers 0.9V. Calculate the internal resistance of the cell

Answer Details

The internal resistance of a cell can be calculated using the equation: r = (E - V)/I where r is the internal resistance of the cell, E is the e.m.f. of the cell, V is the voltage across the cell, and I is the current passing through the circuit. In this case, the e.m.f. of the cell is given as 1.5V, and the resistance of the resistor is 3.0\(\Omega\). Since the cell and the resistor are connected in series, the current passing through them will be the same. We can calculate the current using Ohm's law: I = V/R = 0.9V/3.0\(\Omega\) = 0.3A Now we can use the formula for the internal resistance: r = (E - V)/I = (1.5V - 0.9V)/0.3A = 2.0\(\Omega\) Therefore, the internal resistance of the cell is 2.0\(\Omega\). Answer option A is correct.