Heat Energy Worksheet-7

Heat Energy Worksheet-7

1. Heat causes expansion because

(a) Heat occupies space

(b) Of increase of movement of molecules

(c) Matter tries to escape from the heat

(d) None of these

2. A thermos flask prevents loss or gain of heat by

(a) Conduction only                     (b) Convection only

(c) Radiation only                        (d) All of these

3. Cooking vessels are blackened from the base and kept shining at the sides, because

(a) black bodies are good absorbers of heat and shining bodies are poor radiators of heat

(b) black bodies are poor absorbers of heat and shining bodies are good radiators of heat

(c) black bodies, as well as shining bodies are good absorbers of heat

(d) black bodies, as well as shining bodies are poor radiators of heat

4. A device which can detect the presence of heat radiations is called:

(a) thermometer                           (b) calorimeter

(c) radiation meter                      (d) thermo scope

5. An iron and copper bimetallic strip is heated strongly, and it bends. The iron takes :

(a) the inner edge of bend          (b) the outer edge of bend

(c) any                                             (d) none of these

6. Gaps are left between the rails to allow for :

(a) contraction

(b) expansion

(c) contraction or expansion

(d) for easy transportation of rails

7. The process due to which a liquid changes into solid state, at some fixed temperature, by the release of heat energy is called :

(a) solidification                           (b) freezing

(c) solidification or freezing       (d) none of these

8. The fixed temperature at which a liquid changes into solid state on the release of heat energy is called :

(a) freezing point

(b) solidification point

(c) solidification or freezing point

(d) none of these

9. Wooden handles are provided with cooking Vessels, because :

(a) wood is a heat insulator       (b) wood is a heat conductor

(c) wood looks good                     (d) none of these

10. Vacuum is created in between the two glass bottles of thermos flask, to prevent heat loses by :

(a) conduction                              (b) convection

(c) radiation                                  (d) Conduction or convection

Answer Key:

1. (b)
2. (d)
3. (a)
4. (d)
5. (a)
6. (c)
7. (c)
8. (c)
9. (a)
10. (d)