Q.The resistance of a resistor is reduced to half of its initial value. Indoing so, if other parameters of the circuit remain unchanged, theheating effects in the resistor will become?

(A)

two times.

(B)

half.

(C)

one-fourth.

(D)

four times.​

Ans:- Given Resistance is reduced to half, so resistance = R/2

Also given that, other parameters of circuits remain unchanged,

For constant Current, heating effect of resister will become - 

• This means that Heat is directly proportional to resistance, so when resistance is halfed, then heat effect will also become halfed

For the constant Voltage, heating effect of resistor become - 

• This means that Heat is indirectly proportional to resistance, so when resistance is halfed, then heat effect will also become doubled

So, we found that there are 2 cases, current being constant and voltage being constant. 

Note - Both cases have different answer!

Comment if doubt