# Electricity | Activities in Text Book with Solution

Activity 12.5

In Activity 12.4, insert a voltmeter across the ends X and Y of the series combination of three resistors, as shown in Fig. 12.6.

Plug the key in the circuit and note the voltmeter reading. It gives the potential difference across the series combination of resistors. Let it be V. Now measure the potential difference across the two terminals of the battery. Compare the two values.

Take out the plug key and disconnect the voltmeter. Now insert the voltmeter across the ends X and P of the first resistor, as shown in Fig. 12.8.

Plug the key and measure the potential difference across the first resistor. Let it be V1.

Similarly, measure the potential difference across the other two resistors, separately. Let these values be V2 and V3, respectively.

Deduce a relationship between V, V1, V2 and V3.

✅ Answer: The total potential difference V across a combination of resistors in series is equal to the sum of potential differences across the individual resistors.

i.e., V = V1 + V2 + V3