A $5\; kg$ object is heated by a $50\; W$ power source . If the specific heat capacity of the object is $\;50 Jkg^{-1}K^{-1}\;$ , after what time will the temperature rise by $\;50^{0}C\;.$

Question

$(a)\;4\;mins\;40\;s\qquad(b)\;4\;mins\;20\;s\qquad(c)\;3\;mins\;10\;s\qquad(d)\;4\;mins\;10\;s$