At what temperature do both the Centigrade and Fahrenheit thermometers show the same reading
1. –20$°$

2. –40$°$

3. 42$°$

4. 0$°$

The temperature of substance increases by 27°C this increases is equal to (in kelvin)

1.  300 K

2.  2.46 K

3.  27 K

4.  7 K

In the adjoining figure, various isothermals are shown for a real gas. Then:

The change in volume V with respect to an increase in pressure P has been shown in the figure for a non-ideal gas at four different temperatures ${\mathrm{T}}_1, {\mathrm{T}}_2,{\mathrm{T}}_3$ and ${\mathrm{T}}_4$ . The critical temperature of the gas is

1. ${\mathrm{T}}_1$                                 

2. ${\mathrm{T}}_2$

3. ${\mathrm{T}}_3$                                 

4. ${\mathrm{T}}_4$

The temperature of a substance increases by $27°\mathrm{C}$. On the Kelvin scale, this increase is equal to

1.  300 K

2.  2.46 K

3.  27 K

4.  7 K 

Two rods \(A\) and \(B\) of different materials are welded together as shown in the figure. Their thermal conductivities are \(K_1\) and \(K_2.\) The thermal conductivity of the composite rod will be:
             

The temperature below which gas should be cooled, before it can be liquified by pressure only is termed as :

1. The dew point                           

2. The freezing point

3. The saturation point                   

4. The critical point

The vapour of a substance behaves as a gas :

1. Below the critical temperature                     

2. Above the critical temperature

3. At 100°C                                               

4. At 1000°C

The power radiated by a black body is \(P\) and it radiates maximum energy at wavelength ${}_{}$\(\lambda_0.\) Temperature of the black body is now changed so that it radiates maximum energy at the wavelength \(\dfrac{3}{4}\lambda_0.\) The power radiated by it now becomes \(nP.\) The value of \(n\) is:

The coefficient of linear expansion of brass and steel rods are \(\alpha_1\) and \(\alpha_2\). Lengths of brass and steel rods are \(L_1\) and \(L_2\) respectively. If \((L_2-L_1)\) remains the same at all temperatures, which one of the following relations holds good?
1. \(\alpha_1L_2^2=\alpha_2L_1^2\)
2. \(\alpha_1^2L_2=\alpha_2^2L_1\)
3. \(\alpha_1L_1=\alpha_2L_2\)
4. \(\alpha_1L_2=\alpha_2L_1\)