A current of I ampere is flowing through a resistor R ohm. The rate of heat generated in joules will be :

Question

A current of I ampere is flowing through a resistor R ohm. The rate of heat generated in joules will be : (A) I2R (B) 4.2I2R (C) (I2R/4.2) (D) given by none of the above expressions

Tardigrade Admin · Accepted Answer

Heat produced Q = I2 Rt = (V2/R) t = VIt When R is doubled , keeping V constant Q is halved When V is doubled, Q becomes 4 times, because resistance was not changed As Q = l2Rt in joule, so the rate of production of heat is (Q/t) I2 R

Q. A current of $I$ ampere is flowing through a resistor $R$ ohm. The rate of heat generated in joules will be :

$I^{2} R$

4.2 $I^{2} R$

$\frac{I ^{2} R}{4.2}$

given by none of the above expressions

Heat produced $Q = I^{2} Rt = \frac{V ^{2}}{R} t = V I t$
When R is doubled , keeping V constant Q is halved
When V is doubled, Q becomes 4 times, because resistance was not changed
As $Q = l^{2} Rt$ in joule, so the rate of production of heat is $\frac{Q}{t} I^{2} R$

Q. A current of I ampere is flowing through a resistor R ohm. The rate of heat generated in joules will be :

I2R

4.2I2R

4.2I2R​