Water-A Precious Resource Worksheet-3

Water-A Precious Resource Worksheet-3

1. Why food gets cooked in less time in pressure cooker?

(a) Boiling point of water increases with decrease in pressure

(b) Boiling point of water decrease with increases in pressure

(c) Boiling point of water increases with increase in pressure

(d) None of these

2. Which of the following is used for the purification of surface water to make it free from germs so that it can be used for drinking purposes?

(a) Carbon         (b) Oxygen        (c) Chlorine       (d) Fluorine

3. Why seawater is more saline than river water?

(a) Excreta of aquatic animals contain salt

(b) Salts are also produced in the sea during extraction of oil

(c) Rain water dissolves salt from land and brings them to sea hence the concentration of salt goes on increasing in seawater

(d) Any of these

4. Why the number of cases of diseases like dysentery, diarrhoea, typhoid and cholera are more in villages as compared to urban areas?

(a) The mentioned diseases are water borne diseases, in villages people defecate in the fields and near water bodies

(b) Poor hygiene of villagers is responsible for it

(c) The nutritional condition of villagers is poor which makes them susceptible to these diseases

(d) Any of these

5. What could be the probable reasons for bursting of water pipes in winter in extreme cold regions?

(a) Water expands on freezing and the ice formed inside the pipe exerts pressure on the pipe

(b) Contraction of water pipes may be one of the reasons for bursting

(c) The density of ice formed is high which causes bursting of pipes

6. When the temperature of the region falls below 0 ºC, lakes freeze. In such extreme climatic condition aquatic animals survive. How?

(a) The heat evolved by the activity of aquatic animals melts the ice around them

(b) They create special burrows underneath lake bed where water does not freeze and they hibernate till the next season

(c) Since the density of ice is less as compared to the water, the frozen ice floats over the lake

(d) Lake never freeze as lake water is saline

7. Why the food is cooked faster in the covered utensils?

(a) The steam formed inside the covered vessels has high latent heat of vaporisation which supplies large amount of heat

(b) The water inside has high specific heat capacity which supplies large amount of heat

(c) Any of these

8. Soft drink bottles are cooled by surrounding them with ice because:

(a) Ice has least latent heat of fusion

(b) Ice has highest latent heat of fusion

(c) High specific heat capacity of ice

(d) Low specific heat capacity of ice

9. The level of water table

(a) Does not fluctuate

(b) Variable as it depends on rainfall

(c) Rarely levelled and follows the general slope of land above

(d) Variable as it depends on rainfall & Rarely levelled and follows the general slope of land above

10. The amount of water drunk per person each day should be

(a) 1 litres          (b) 4 litres         (c) 2 litres             (d) 3 litres

Answer Key:

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