Question

An ammeter placed in a series with a resistor reads 200 milliampere and a voltmeter connected in parallel with a resistor reads 2 v.what is the resistance of the resistor?

Answer 1

ANSWER

Total current in ammeter is 0.8 A

Current through 20 ohm resistor is 0.3 A, hence the voltage across it is

V=0.3×20=6V

Current through 15 ohm resistor is

I=

R

V

=

15

6

=0.4A

Hence current through R1 is, I' = 0.8 - (0.3+0.4) = 0.1 A

Therefore,

R1=

I

′

V

=

0.1

6

=60Ω