Question

board question about electricity

Answer 1

Answer                                                    

In first case

1.length=l

R=4 ohm

So,

R=pl/A

4=pl/A - first equation

In second case

Length=3l

R=?

So,

R=pl/A

R=p3l/A

R=3pl/A

Pl/A=4 by first equation

Put value of pl/A

R=3×4

R=12

New Resistance

2.ratio of current

Potential difference is same across each of their length

So,

We assume that potential difference is 1 volt in both cases

Ratio of current is

V/R/V/R

V/R×R/V

Reciprocal

V is same so it is cut by each other

R/R

4/12

1/3 ratio of current

Ans.