Question

a voltmeter has resistance 30 ohm what will be it's reading when it's connected across a cell of 2 emf V having internal resistance 10​

Answer 1

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Given :

A voltmeter has a resistance 30 Ω, a cell of emf 2 V, internal resistance 2 Ω.

To Find :

Reading of voltmeter (V)

Solution :

We know that, current can be calculated as:

I = E/R + r

So, putting the values in formula, we get:

I = 2/30 + 10

I = 2/40

I = 1/20 Ampress

Now we know the formula:

V = E - Ir

V = 2 - (1/20) ×10

V = 2 - 1/2

V = 3/2

V = 1.5

The reading of voltmeter (V) is 1.5 V.

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