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A battery of e.m.f. 6.0 V supplies current through a circuit in which the resistance can be changed. A high resistance voltmeter is connected across the battery. When the current is 3 A, the voltmeter

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Question

A battery of e.m.f. 6.0 V supplies current through a circuit in which the resistance can be changed. A high resistance voltmeter is connected across the battery. When the current is 3 A, the voltmeter reads 5.4 V. Find the internal resistance of the battery.

Numerical
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Solution

Since a battery's terminal potential difference is less than its e.m.f., an increase in circuit current causes the voltmeter reading to fall.

Now E = 6.0 V,

V = 5.4 V,

I = 3.0 A

Internal resistance r = `("E" - "V")/"I"`

= `(6 - 5.4)/3.0`

= `0.3/1.5`

r = 0.2 Ω

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Chapter 8: Current Electricity - EXERCISE - 8(B) [Page 201]

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Selina Concise Physics Part 2 [English] Class 10 ICSE
Chapter 8 Current Electricity
EXERCISE - 8(B) | Q 2. | Page 201

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