1. Consider the following statements : If there were no phenomenon of capillarity 1. it would be difficult to use a kerosene lamp 2. one would not be able to use a straw to consume a soft drink 3. the blotting paper would fail to function 4. the big trees that we see around would not have grown on the Earth
Which of the statements given above are correct?
1, 2 and 3 only
1, 3 and 4 only
2 and 4 only
1, 2, 3 and 4
2. Electrically charged particles from space travelling at speeds of several hundred km/sec can severely harm living beings if they reach the surface of the Earth. What prevents them from reaching the surface of the Earth?
The Earth’s magnetic field diverts them towards its poles
Ozone layer around the Earth reflects them back to outer space
Moisture in the upper layers of atmosphere prevents them from reaching the surface of the Earth
None of the statements (a), (b) and (c) given above is correct
3. Lead, ingested or inhaled, is a health hazard. After the addition of lead to petrol has been banned, what still are the sources of lead poisoning ? 1. Smelting units
2. Pens and pencils 3. Paints
4. Hair oils and cosmetics
1 and 3 only
4. What is the role of ultraviolet (UV) radiation in the water purification systems? 1. It inactivates /kills the harmful microorganisms in water. 2. It removes all the undesirable odours from the water. 3. It quickens the sedimentation of solid particles, removes turbidity and improves the clarity of water.
Which of the statements given above is/are correct?
1 only
2 and 3 only
1, 2 and 3
5. Consider the following kinds of organisms :
1. Bacteria
2. Fungi 3. Flowering plants
Some species of which of the above kinds of organisms are employed as biopesticides?