A very small hole in an electric furnace is used for heating metals. The hole nearly acts as black body. The area of the hole is `200mm^(2)` To keep a metal at `727^(@)C` heat energy flowing throungh this hole per sec in joules is `(sigam =5.67 xx 10^(-8)Wm^(-2)K^(-4))` .

A very small hole in an electric furnace is used for heating metals. The hole nearly acts as black body. The area of the hole is 200mm^(2) To keep a metal at 727^(@)C heat energy flowing through this hole per sec in joules is (sigma =5.67 xx 10^(-8)Wm^(-2)K^(-4)) .

A very small hole in an electric furnance is used for heating metals . The hole nearly acts as a black body . The area of the hole is 200 mm^(2) . To keep a metal at 727^@C , heat energy flowing through this hole per sec, in joules is ( sigma= 5.67 xx 10^(-8)Wm^(-2)K^(-4) )

The surface area of a black body is 5xx10^(-4) m^(2) and its temperature is 727^@C . Energy radiated by it per minute is (Take sigma =5.67xx10^(-8) "J m"^(-2) s^(-1) K^(-4) )

The surface area of a black body is 5xx10^(-4) m^(2) and its temperature is 727^@C . Energy radiated by it per minute is (Take sigma =5.67xx10^(-8) "J m"^(-2) s^(-1) K^(-4) )

The surface of a black body is at a tempera ture 727^(@)C and its cross section is 1m^(2) Heat radi ated from this surface in one minute in Joules is (Stefan's constant =5.7 xx 10^(-8) W//m^(2)//k^(4)) .

The surface of a black body is at a temperature 727^(@)C and its cross section is 1m^(2) Heat radiated from this surface in one minute in Joules is (Stefan's constant =5.7 xx 10^(-8) W//m^(2)//k^(4)) .