Question

In an experiment on a circuit, as shown in the figure, the voltmeter shows 8V reading. The resistance of the voltmeter is

• A. 20Ω
• B. 320Ω
• C. 160Ω
• D. 1.44kΩ

Answer 1

Answer: (C)

160Ω

Answer 2

Given the values: I=10Ω8 volts=5/4=0.8 A I =8 volts10Ω​=45​=0.8 A Voltage across 5Ω5Ω: V 1​=(0.8)×5=V 1​=4 volts

Hence, the electromotive force (e.m.f) of the battery is equal to the voltage across 10Ω10Ω, which is:

EMF=8+4=EMF=12 voltsEMF=8+4=EMF=12 volts

Therefore, the correct option is 160Ω.

The correct option is(C): 160Ω