Answer
(b) the 6-ohm resistor
Work Step by Step
$R_{1}=2ohm$
$R_{2}=6ohm$
Current will be same i.e. $I$.
Joule heating is same as the power output of the resistors.
$P_{1}=I^{2}R_{1}$
$P_{2}=I^{2}R_{2}$
Thus, $P_{2}=3P_{1}$
Clearly, the resistor with 6-ohm resistance will produce more Joule heating. Thus the answer is (b).
