Question

what will be the current through a resistor,if the potential difference across it is doubled and the resistance is halved??

Answer 1

Resistance(R)=Potential Difference(V)/Current(I)

Hence,I=R/V I1/I2=R1R2/V1V2

let R1=1 and V1=1,I1=1

R2=0.5 and V2=2,I2=to find(let it be x)

1/x=0.5/2,1/x=0.25=25/100

x=100/25=4

therefore,current through the resistor is original current*4

Answer 2

let the P.D across the ends be V and the total resistance be R

Original Current

I=V/R ....by ohms law

new current

I=4V/R  ....... by ohms law

I=4I

so current will increase by 4 times