One kilogram of ice at $0°$C is mixed with one kilogram of water at 80$°C$. The final temperature of the mixture is (Take: Specific heat of water = 4200 J $k{g}^{-1}{C}^{-1}$, Latent heat of ice = 336 kJ $k{g}^{-1}$)

(1) $0°$C              (2) $50°C$

(3) $40°C$           (4) $60°C$

The fastest mode of heat transfer is 

1.  Conduction

2.  Radiation

3.  Convection

4.  all are  equally fast

A temperature of 100 ^oF (Fahrenheit scale) is equal to T K (Kelvin scale). The value of T is:

1.  310.9

2.  37.8

3.  100

4.  122.4

A black body at temperature 300K radiates heat at the rate E. If its temperature is increased by 600K, the rate of radiation will increase to -

1.  16E

2.  64E

3.  81E

4.  256E

A body cools down from $80°\mathrm{C} \mathrm{to} 70°\mathrm{C}$ in 5 minutes. The temperature of the body will fall from $70°\mathrm{C} \mathrm{to} 60°\mathrm{C}$ in a time:

1.  less than 5 minutes.

2.  equal to 5 minutes.

3.  more than 5 minutes.

4.  can't say anything like the temperature of surroundings is not known.

If ${\lambda }_m$ is the wavelength, corresponding to which the radiant intensity of a block is maximum and its absolute temperature is T. Which of the following graph correctly represents the variation of ${\lambda }_m$ with T.

1.   

2.  

3.   

4.  

Heat capacity is equal to the product of:

1.  mass and gas constant

2.  mass and specific heat

3.  latent heat and volume of water

4.  mass and Avogadro number

When a block of iron floats in Hg at $0°C$, a fraction $K_1$ of its volumen= is submerged, while at temperature of $60°C$ a fraction $K_2$ is seen to be submersed. If the coefficient of volume expansion of iron is ${\gamma }_{Fe}$ and that of mercury is ${\gamma }_{Hg}$, then the ratio $\frac{K_1}{K_2}$ can be expressed as:

1. $\frac{1+60{\gamma }_{Fe}}{1+60{\gamma }_{Hg}}$

2. $\frac{1-60{\gamma }_{Fe}}{1+60{\gamma }_{Hg}}$

3. $\frac{1+60{\gamma }_{Fe}}{1-60{\gamma }_{Hg}}$

4. $\frac{1+60{\gamma }_{He}}{1-60{\gamma }_{Fe}}$

Hot water cools from 60$°\mathrm{C}$ to 50$°\mathrm{C}$ in first 10 minutes and from 50$°\mathrm{C}$ to 42$°\mathrm{C}$ in next 10 minutes. The temperature of surrounding is :

1.  $5° \mathrm{C}$

2.  $10° \mathrm{C}$

3.  $15° \mathrm{C}$

4.  $20°\mathrm{C}$

A pendulum clock runs fast by 5 sec per day at 20 ^oC and goes slow by 10 sec/day at 35 ^oC. It shows the correct time at a temperature of:

1.  27.5 ^oC

2.  25 ^oC

3.  30 ^oC

4.  33 ^oC