Question

Two resistors are connected in series across a battery as shown in the figure. If a voltmeter of resistance 2000 Ω is used to measure the potential difference across 500 Ω resistors, the reading of the voltmeter will be ______ V.

Options

• 5

• 7

• 8

• 10

Answer 1

Two resistors are connected in series across a battery as shown in the figure. If a voltmeter of resistance 2000 Ω is used to measure the potential difference across 500 Ω resistors, the reading of the voltmeter will be 8 V.

Explanation:

According to the question, the required figure is as follows:

2000Ω and 500Ω are in parallel, hence,

`1/R = 1/2000 + 1/500`

`1/R = (500 + 2000)/(2000 xx 500)`

`1/R = 2500/(1000000)`

R = 400Ω

Because R and 600Ω are connected in series, the net resistance is,

R = 400 + 600

R = 1000Ω

Circuit current, I = `20/(600 + 400) = 20/1000`

I = `1/50` A

Now consider the voltmeter reading,

V = IR ..............(1)

`V = 1/50 xx 400`

V = 8 volts