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Question:

The measurement of voltmeter in the following circuit is 2.4 V, 3.4 V, 4.0 V, 6.0 V

3.4 V

4.0 V

2.4 V

6.0 V

Solution:

Resistance of voltmeter and 60Ω are in parallel.
∴Equivalent resistance = 60 × 40 / (60 + 40) = 60 × 40 / 100 = 24Ω
For the whole circuit, current I = 6V / (40 + 24)Ω = 6 / 64 = 3/32 A
The voltmeter reads potential difference across 60Ω.
∴Voltmeter reading = I × Req = (3/32) × 24 = 9/4 V = 2.25 V.