Question

Assuming the cell and ammeter to be ideal and resistance of voltmeter is $600\Omega$ the reading of voltmeter and ammeter are respectively.

• A. $100V,0.5A$
• B. $200V,0$
• C. $0.0$
• D. none of these

Answer 1

Answer: (A)

$100V,0.5A$

Resistance of voltmeter = 600 Ohm

Source voltage, V = 200 V

The two resistances of 600 ohm are in parallel with the voltmeter.

Therefore their equivalent resistance will be $R_{e}q$ = $\frac{1}{600}+\frac{1}{600}+\frac{1}{600}$

= $\frac{3}{600}=\frac{1}{200}$

$R_{e}q=200$ Ohm

Now $R_{e}q$ and 200 Ohm resistance are in series. Therefore equivalent resistance for the circuit will be 400 Ohm

As $V=IR$ $\to$ $I=\frac{V}{R}$

$I=\frac{200}{400}$ = 0.5 A

Hence the Ammeter will read 0.5 A.

Now , $R_{e}q$ is 200 Ohm. So the 200 V is distributed into two parts (100 V each) among $R_{e}q$ and 200 Ohm resistance. Hence Voltmeter will read 100 V.

Reading of Ammeter is 0.5 A and reading of Voltmeter is 100 V.

Option A