Question

Read the sources given and answer any four from the questions given below:

Normally the air is warmer near the ground than higher up and so as warm air rises, the smoke from the factories gets carried upwards and is dispersed. But in certain conditions, a layer of warm air develops high up in atmosphere. This holds down the cooler air underneath, thus preventing the smoke from rising. The warm layer above prevents the cooler air underneath from escaping. It leads to the formation of smog which remains suspended in the air. Photochemical smog occurs in sunny places and is caused by the action of UV radiations of sunlight and the exhaust released from automobiles. It occurs in traffic congested areas and results in a brown haze depending on the intensity of sunlight. It contains secondary pollutants like ozone and PAN which are harmful to animals as well as plants. PAN damages chloroplasts in leaves and causes acute irritation in eyes.

1. Smog gets formed when the
   1. air near the ground is warmer than high up air
   2. air near the ground is cooler than high up air
   3. high winds occur on warm days
   4. clouds cover the sky
2. Photochemical smog gets formed as a result of action of
   1. carbon dioxide and smoke
   2. carbon monoxide and smoke
   3. UV rays of sunlight and exhaust gases
   4. dust and sunlight
3. Smog contains secondary pollutants like
   1. carbon monoxide
   2. PAN
   3. ozone
   4. both (b) and (c)
4. The effect of smog on plants is
   1. damage to chlorophyll of leaves
   2. transpiration becomes more
   3. respiration becomes slow
   4. roots get damaged
5. The smoke from factories, normally goes up in the atmosphere because
   1. it rises up with the warm air coming from surface of earth.
   2. it rises up with the cool air coming from surface of earth.
   3. it moves towards the warm layer of upper atmosphere.
   4. it contains ozone that rises up.

Answer 1

1. air near the ground is cooler than high up air
2. UV rays of sunlight and exhaust gases
3. both (b) and (c)
4. damage to chlorophyll of leaves
5. it rises up with the warm air coming from surface of earth.