# Internal Resistance

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#1
Hey guys, can you check whether my answer to the following question is correct or not?

A battery, emf of 2.0V, of internal resistance 1.0 ohms, is connected to an external resistor R. A voltmeter is connected across the terminals of R. When the switch is closed, the reading on the voltmeter is 1.6V. Calculate the value of R.

So I worked out that the value of lost volts is 0.4V, and divided this by 1.0 ohms to calculate the current as 0.4A.
So to calculate R, I did 1.6 / 0.4 = 4.0ohms.
Is this correct?
Thank you
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#2

This is what the diagram of the circuit looks like if that helps/
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#3
Bump
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1 month ago
#4
yes, you could also do another way

emf= I(R+r)

rearrange for R
R=(emf/I) -r
= (2/0.4) -1
R=4
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#5
(Original post by gorilla_08)
yes, you could also do another way

emf= I(R+r)

rearrange for R
R=(emf/I) -r
= (2/0.4) -1
R=4
Thank you Sir, I appreicate it
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