Question

how many 12 ohm resistors in parallel are required to carry 2A on 4v batery

Answer 1

Acc. To me,

Suppose you join 3 resistor in parallel thn

1/R=1/12+1/12+1/12

1/R=3/12=1/4

R=4

Similarly

If you add x resistor in parallel then

1/R=1/12+1/12+1/12....x times

So you see above 3 resister join then

1/R=3/12

Similarly for x resistors(x denote no. of resistor join in parallel)

1/R=x/12

R=12/x

You know current,voltage and resistance

Then ohm's law

V=IR

V=4

I=2

R=12/x

Put it 4=2*12/x

x=6

So 6 resistor is added.

I hope it help