According to stephen Boltzman Law ,
Heat loss by a black body (E)α(T4−T04)
or E1E2=(T41−T40)(T42−T40) ...... (A)
T1= temperature of the body
T0 =temperature surrounding
Given, T1=7270c,T2=12270c,T0=2270c
E1=20watt
Putting the above values in A, we get,
E2=E1(T42−T40)((T41−T40)
==20(12274−2274)(7274−2274)=166.40w