Blackbody

Q. Which of the following is not a cause of global warming?

1. Increased $\text{CFCs}$
2. Rise of new viruses
3. Deforestation
4. Nitrous oxide

Q. A black body is heated from ${27}^{\circ }$ C to ${127}^{\circ }$ C. The ratio of their energies of radiations emitted will be

1. 3: 4
2. 9 : 16
3. 27 : 64
4. 81: 256

Q.

The following figure shows two air-filled bulbs connected by a U-tube partly filled with alcohol. What happens to the levels of alcohol in the limbs X and Y when an electric bulb placed midway between the bulbs is lighted.

1. The level of alcohol in limb X falls while that in limb Y rises
2. The level of alcohol in limb X rises while that in limb Y falls
3. The level of alcohol falls in both limbs
4. There is no change in the levels of alcohol in the two limbs
   

Q.

An electric heater raises the temperature of 500 g of a given liquid from 25 ^OC to 31 ^OC in 120 seconds. If the power of heater is 1 kW, Calculate:

Specific Heat capacity of the liquid.

Q. The spectrum from a black body radiation is a

1. Line spectrum
2. Band spectrum
3. Line and band spectrum both
4. Continuous spectrum

Q. What is a thermopile and how does it work ?