Question

A solid at temperature `T_(1)` is kept in an evacuated chamber at temperature `T_(2)gtT_(1)` . The rate of increase of temperature of the body is proportional to
A. `t_(2)^(4)-t_(1)^(4)`
B. `(t_(4)^(2)+273)-(t_(1)^(4)+273)`
C. `t_(2)-t_(1)`
D. `t_(2)^(2)-t_(1)^(2)`

Answer 1

Correct Answer - C
c) As we know that, the rate of cooling is
`(dtheta)/(dt) = bA(theta-theta_(0))`
where, bA=constant
`rArr (dtheta)/(dt) alpha (theta-theta_(0))`
Also `-(dT)/(dt) alpha T-T_(0)`
where, T=temperature and t=time
So, the rate of heat absorbed by cooled body is proportional to `t_(2)-t_(1)`.