## For an enclosure maintained at 1000K the maximum radiation occurs at wavelength λm …

Q: For an enclosure maintained at 1000K the maximum radiation occurs at wavelength λm . If the temperature is raised to 2000K, the peak will shift to

(a) 0.5 λm

(b) λm

(c) 4 λm

(d) 8 λm

Ans: (a)

## The rates of cooling of a body at temperatures 100°C and 80°C are x1 and x2 respectively…

Q: The rates of cooling of a body at temperatures 100°C and 80°C are x1 and x2 respectively, when placed in a room of temperature 40°C then x1/x2 is

(a) 4/5

(b) 5/4

(c) 3/2

(d) 2/3

Ans: (c)

## Two bodies of same shape, same size and same radiating power have emissivity 0.2 and 0.8..

Q: Two bodies of same shape, same size and same radiating power have emissivity 0.2 and 0.8. The ratio of their temperature is

(a) √3 ∶ 1

(b) √2 ∶ 1

(c) 1 ∶ √5

(d) 1 ∶ √5

Ans: (b)

## One end of a cylindrical rod is kept in steam chamber and the other end in melting Ice. Now 0.5 gm of ice melts…

Q: One end of a cylindrical rod is kept in steam chamber and the other end in melting Ice. Now 0.5 gm of ice melts in 1sec. If the rod is replaced by another rod of same length, half the diameters and double the conductivity of the first rod, then rate melting of ice will be (in gm/ sec)

(a) 0.25

(b) 0.5

(c) 1

(d) 2

Ans: (a)

## A liquid of mass ‘m’ and specific heat ‘S’ is at a temperature ‘2t’. If another liquid of thermal capacity…

Q: A liquid of mass ‘m’ and specific heat ‘S’ is at a temperature ‘2t’. If another liquid of thermal capacity 1.5 times, at a temperature of t/3 is added to it, the resultant temperature will be

(a) 4t/3
(b) t
(c) t/2
(d) 2t/3

Ans: (b)