Q3) you are provided with two(1.5V) batteries, a battery holder,a known resistor, an ammeter, voltmeter an some crocodile clips.use the equipment to determine the internal resistance of one of the battery

Connect the voltmeter directly across the terminals of one of the 1.5V batteries. This reading, taken when no current is flowing, represents the electromotive force ($E$) of the battery. Record this value.

Connect the battery holder with one 1.5V battery, the known resistor, and the ammeter in series using the crocodile clips. Ensure the ammeter is connected correctly to measure the current flowing through the circuit.

Connect the voltmeter in parallel across the terminals of the battery (while it is connected in the series circuit with the resistor and ammeter). This reading represents the terminal voltage ($V$) of the battery when current is flowing. Read the current ($I$) from the ammeter.

The relationship between EMF ($E$), terminal voltage ($V$), current ($I$), and internal resistance ($r$) is given by the formula:

Rearrange the formula to solve for the internal resistance ($r$):

Substitute the values you measured for $E$, $V$, and $I$ into this equation to calculate the internal resistance of the battery.