Q. 485.0( 2 Votes )
A voltmeter of re
Resistors in Series:
Resistors in parallel:
Potential Difference (V) across a resistor of resistance R when current I passes through it is given by Ohm’s law:
The given circuit is:
We can easily see that the voltmeter and R1 are in parallel. The equivalent resistance, r’ is given by:
We can redraw the circuit as follows:
Note that r’ and R2 are in series. The equivalent resistance is given by:
The current coming out of the battery also passes through r’. By Ohm’s law,
Now, the voltmeter reads the potential different across R1 .
Hence, the voltmeter reads 24V.
The given circuit is now:
The equivalent resistance is :
The current is the same throughout the circuit as all components are in series and is given by:
Now, the potential difference across R1 is given by:
Hence, the potential difference across the 100Ω resistor before connecting the voltmeter was 28V.
Rate this question :
Let there be n rePhysics - Exemplar
Two cells of emfPhysics - Exemplar
Kirchhoff ’s juncPhysics - Exemplar