Question

Question 2
Redraw the circuit of question 1, putting in an ammeter to measure the current through the resistors and a voltmeter to measure potential difference across the $12\Omega$ resistor. What would be the readings in the ammeter and the voltmeter?

Answer 1

An ammeter should be connected in the circuit in series with the resistors. To measure the potential difference across the resistor the voltmeter should be connected in parallel, as shown in the following figure.

The resistances are connected in series. Ohm’s law can be used to obtain the readings of ammeter and voltmeter.
According to Ohm’s law, V = IR
where, potential difference, V = 6 V
Resistance of the circuit, $R=5+8+12=25\Omega$
$I=\frac{V}{R}=\frac{6}{25}=0.24A$
Potential difference across $12\Omega$ resistor = $V_1$
Current flowing through the $12\Omega$ resistor, I = 0.24 A
Therefore, using Ohm’s law, we obtain $V_1=IR=0.24\times 12=2.88V$
Therefore, the reading of the ammeter will be 0.24 A.
The reading of the voltmeter will be 2.88 V.