A sysem is supplied power of 10 W. Temperature of the system becomes constant at 50^(@)C. With temperature of surrounding at 20^(@)C. When power is switched off system cools from t^(@)C to (t//m)^(@)C in one minute. The heat capacity of the system is 1200 J//^(@)C. find the limiting value of n.

A sysem is supplied power of 10 W. Temperature of the system becomes c

1.	A sysem is supplied power of 10 W. Temperature of the system becomes constant at 50^(@)C. With temperature of surrounding at 20^(@)C. When power is switched off system cools from t^(@)C to (t//m)^(@)C in one minute. The heat capacity of the system is 1200 J//^(@)C. find the limiting value of n.
Answer» `n ge 75` `n ge 55` `n ge 60` `n ge 100` SOLUTION :`(dQ)/(DT) = K(50-20)=10, so K=1//3` Heat lost in 1 minute = `(dQ)/(dt)xx60(J)=Q` `(dQ)/(dt) = 1/3 (t-20)` Fall in temperature=`t//n` `C = (Q)/(Delta theta) = ((1//3)xx(t-20)xx60)/((t//n))` PUTTING values, `1200=20n=(400n)/(t)` Since `t gt 0` so `20n gt 1200` `n ge 60`.