Question

Heater coil connected across a given potential difference has power bi now the coil is cut into two equal halves and joined in parallel across the same potential difference the combination has the power

Answer 1

Answer:

Heater coil connected across a given potential difference has power bi now the coil is cut into two equal halves.

Explanation:

The coil has resistance R  

The coil is cut into two equal halves produces 2 coils of resistance R/2 each.

Connecting these in parallel,

1/R'=2/R+2/R

1/R'=4/R

R'=R/4

where, R'=total resistance

So the resistance has decreased by a factor 4.  

P=V^2/R

power is inversely proportional to R when V is constant.

As R has decreased by a factor 4, P increases by a factor 4.