Question 950011
The heat capacity of water is 4.18 J/(gK).
{{{Q=mC[p]*(T[f]-T[0])}}}
{{{Q=(800)(4.18)(100-20)}}}{{{J}}}
{{{Q=267520}}}{{{J}}}
Assuming 100% efficiency,
{{{1}}} {{{W}}} ={{{1}}} {{{J/s}}}
{{{1}}} {{{kW}}}={{{1000}}}{{{J/s}}}
.
.
{{{t=267520/(1000)}}}
{{{t=267.52}}}{{{s}}}