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Liono4ka [1.6K]
3 years ago
10

A battery has an emf of 15.0 V. The terminal voltage of the battery is 12.2 V when it is delivering 14.0 W of power to an extern

al load resistor R. (a) What is the value of R?
(b) What is the internal resistance of the battery?
Physics
1 answer:
solong [7]3 years ago
3 0

Answer:

The value of R and the internal resistance of the battery are 10.6 ohm and 2.45 ohm

Explanation:

Given that,

Emf of battery = 15.0 V

Voltage = 12.2 V

Power = 14.0 W

(a). We need to calculate the value of R

Using formula of power

P=IV

P=\dfrac{V^2}{R}

R=\dfrac{V^2}{P}

Where, R = resistance

P = power

V = voltage

Put the value into the formula

R =\dfrac{(12.2)^2}{14.0}

R=10.6\ \Omega

(b). We need to calculate the internal resistance of the battery

Firstly we calculate the current

Using formula of current

I=\dfrac{V}{R}=\dfrac{P}{V}

Put the value of P and V into the formula

I =\dfrac{14}{12.2}

I=1.14\ A

We calculate the internal resistance

Using formula of emf

e-V=Ir

r =\dfrac{e-V}{I}

Put the value into the formula

r=\dfrac{15.0-12.2}{1.14}

r = 2.45\ \Omega

Hence, The value of R and the internal resistance of the battery are 10.6 ohm and 2.45 ohm

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