Question

A resistor develops $300\, J$ of thermal energy in $15\, s$, when a current of $2 \,A$ is passed through it. If the current increases to $3\, A$, the energy developed in $10\, s$ is ______$J$.

Answer 1

$H = i ^{2} Rt $
$300=2^{2} \times R \times 15 $
$\Rightarrow R =\frac{300}{60}=5\, \Omega$
Now, for $i =3\, A , t =10 \,s , R =5\, \Omega$
$H =3^{2} \times 5 \times 10=450\, J$