A 10 V full-scale voltmeter having 100 k-ohm/V sensitivity

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A 10 V full-scale voltmeter having 100 k-ohm/V sensitivity is used to measure the output of a photovoltaic cell having an internal resistance of 1 M-ohm. The voltmeter reads 5V. The voltage generated by the photovoltaic cell is:

1. 5V
2. 10V
3. greater than 5V but less than 10V
4. greater than 10V

Correct Option: B

Let the voltage generated by the photovoltaic cell is E.
Given, Sensitivity of voltmeter = 100 k-ohm/V
Internal resistance of photovoltaic cell,
R_r = 1MΩ
Voltmeter range = 0–10V
Voltmeter range = 5V
The resistance of voltmeter
= Sensitivity × Maximum voltmeter range
= 100 k-ohm/V × 10 = 1MΩ
I_fsd = 1/sensitivity = 1/100 k-ohm/V = 10μA
Now, combining these information with the help of circuit diagram given below:
From above figure we conclude that
E = 10V