Tissues — Science STD 9 — Question

Which of the following represents the solubility of sugar in water at 20°C?

Mark the incorrect statements:
(a) intensity of sound depends on the response of our ears
(b) loudness can be measured as a physical quantity
(c) loudness is a subjective quantity.

The relative densities of four liquids P, Q, R and S are 1.26, 1.0, 0.84 and 13.6 respectively. An object is floated in all these liquids, one by one. In which liquid the object will float with its maximum volume submerged under the liquid?

Leaves are the food factories of plant”. But, how does cactus (desert plants) carry out photosynthesis?

Which of the following is incorrect for green manure?

Find out the correct sentence about manure.

1. Manure contains large quantities of organic matter and small quantities of nutrients.
2. It increases the water holding capacity of sandy soil.
3. It helps in draining out of excess of water from clayey soil.
4. Its excessive use pollutes environment because it is made of animal excretory waste.

Which of the following is not a property of particles of matter:

For an element, Z = 9. The valency of this element will be:

1. 4
2. 2
3. 1
4. 3

One of the following liquids will leave behind a residue on heating. This one is:

1. Brine.
2. Bromine.
3. Mercury.
4. Alcohol.

The sound waves travel fastest:

1. In solids.
2. In liquids.
3. In gases.
4. In vacuum.