Question

A student arranges the following circuit to get equivalent resistance of a series combination of two resistors R1 and R2 Which one of the following statements will be true for this circuit [CCE 2007] (a) It gives incorrect reading for current I as well as potential difference V (b) It gives correct reading for current I but incorrect reading for potential difference V (c) It gives correct reading for potential difference V but incorrect reading for current I (d) It gives correct reading for both I and V

Answer 1

Answer:

It gives correct reading for both I and V

Answer 2

The true statement is (b) It gives correct reading for current I but incorrect reading for potential difference V.

The image given in the question is attached below.

Ammeter:

• It is used to measure the amount of current passing through the circuit.
• It has very low resistance.
• When it is connected in series, it measures the current properly.
• When it is connected in parallel, it gets short circuited. This is because it has low resistance.
• So, in the given circuit, the current is measured properly.

Voltmeter:

• It is used to measure the potential difference across the circuit.
• It has very high resistance.
• When it is connected in series, the current does not flow through it (high resistance) and it shows incorrect reading.
• When it is connected in parallel, it shows the potential difference.
• In the given circuit, the potential difference is not measured properly because it is not parallel to the resistors.