A body cools in a surrounding of constant temperature `30^@C` Its heat capacity is `2 J//^(@)C`. Initial temeprature is `40^@C` and newton law of cooling is valid. The body of mass 1kg cools to `38^@C` in 10 min
When the body temperature has reached `38^@C`, it is heated again so that it reches `40^@C` in 10 min. The heat required from a heater by the body is

Options

A. 3.6 J
B. 0.364J
C. 8J
D. 4J

Explanation

During heating process from 38 to 40 in 10 min. The body will lose heat in the surrounding which will exactly equal to the heat lost when it cooled from 40 to 38 in 10 min, which is equal to ms `triangletheta=2xx2=4`
J. During heating process heat required by the body `=mstriangletheta=4J`
`therefore` total heat required `=8J`.