Question

If you have three wires having resistance R ohm each. In which way they should be connected to obtain resultant resistance 2/3 R ? Give your explanation with suitable circuit diagram and if in one wire, 4 ampere current flows in 10 second by connecting it separately with electric battery, then calculate number of electrons passing through that wire.

Answer 1

The diagram of three resistors connected in series combination is shown.

R1,R2 and R3 are the three resistors.

I = electric current flowing through the circuit

V = the potential difference supplied by the battery

Applying the Ohm’s law to the entire circuit, we have

V=IR

On applying Ohm’s law to the three resistors separately, we further have

V1=IR1

V2=IR2

and V3=IR3

The total potential difference across a combination of resistors in series is equal to the sum of potential difference across the individual resistors. That is,

V=V1+V2+V3

Therefore, IR=IR1+IR2+IR3

or

Equivalent resistance of the combination, R=R1+R2+R3