Problem 19.31 An idealized voltmeter is connected across the terminals of a 16.5
ID: 1528856 • Letter: P
Question
Problem 19.31
An idealized voltmeter is connected across the terminals of a 16.5-V battery, and a 71.5-appliance is also connected across its terminals. If the voltmeter reads 11.6 V .
Part A
How much power is being dissipated by the appliance?
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Part B
What is the internal resistance of the battery?
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Problem 19.31
An idealized voltmeter is connected across the terminals of a 16.5-V battery, and a 71.5-appliance is also connected across its terminals. If the voltmeter reads 11.6 V .
Part A
How much power is being dissipated by the appliance?
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Part B
What is the internal resistance of the battery?
r =SubmitMy AnswersGive Up
Explanation / Answer
given that
V = 16.5 V
R = 71.5 ohm
voltmeter reading = 11.6 V
given that it is an idealised voltmeter, no current flows through it. Thus, all the current flows from the battery to the 71.5 ohm appliance. Also, the volmeter shows the voltage drop across the battery or the negative voltage drop across the appliance.
Thus, the current through appliance = 11.3 / 71.5 = 0.158 Amp
(a)
The power dissipated by appliance = I^2*R = (0.158)^2*71.5 = 1.78 W
(b)
The difference voltage must have fallen due to the internal resistance. Thus,
r = (16.5 - 11.6) / 0.158 = 31.01 ohms