Pollution of Air & Water

Pollution of Air and Water Worksheet-7

1. In which part of atmosphere, ozone layer is present?

(a) Stratosphere                           (b) Troposphere

(c) Mesosphere                             (d) Thermosphere

2. There is a possibility of melting of polar ice caps and increase in the level of sea water due to:

(a) depletion of ozone layer        (b) green house effect

(c) acid rain                                   (d) all of these

Pollution of Air and Water Worksheet-8

1. What are the effects of discharging excess heat from electrical power stations into rivers and lakes?

I – The biological oxygen demand value of the water decreases.

II – Instant death of certain organisms.

III – The population of algae increases.

IV – The concentration of dissolved oxygen increases.

(a) I and IV only                           (b) II and III only

(c) I, II and III only                      (d) II, III and IV only

Pollution of Air and Water Worksheet-9

1. Gases in the Earth's atmosphere prevent heat from going out into space. They keep the Earth warm. When a forest is burnt, more of these gases are released into the atmosphere. This may cause _____

(i)   Some organisms to die                          

(ii)  The Earth to get warmer,

(iii) Plants to stop making food.                  

(iv) Changes in weather patterns

(a) Some organisms to die & The Earth to get warmer,

(b) The Earth to get warmer & Plants to stop making food

(c) Some organisms to die, The Earth to get warmer & Plants to stop making food