A student uses a series circuit to find the resistance of a component X. The circuit contains a cell, a variable resistor, component X and an ammeter, all connected in series. A voltmeter is connected across component X.
Explain why the ammeter must be connected in series with component X.
Give one way the student could change the potential difference across component X.
The voltmeter reads 2.4 V and the ammeter reads 0.30 A. Calculate the resistance of component X. Use the equation: potential difference=current×resistance\text{potential difference} = \text{current} \times \text{resistance}potential difference=current×resistance
The student replaces component X with a resistor of higher resistance. The setting of the variable resistor is not changed. Explain the effect on the reading on the ammeter.