Atoms and Molecules — Science STD 9 — Question

When salt is dissolved in water _______________?

What is known as thrust:

Which of the following are homogeneous in nature?

1. Ice
2. Wood
3. Soil
4. Air

1. (i) and (iii)
2. (ii) and (iii)
3. (i) and (iv)
4. (iii) and (iv)

An object attached to one end of a spring makes 20 vibrations in 10s. Its frequency is:

During evaporation of liquid,  ___________?

The centre for cellular and molecular biology is located at:

When a force retards the motion of a body, the work done is:

Male Ascaris can be distinguished from female ones by:

1. Urved posterior.
2. Round shape end.
3. Presence of penial setae.
4. Both (a) and (c).

An apple of mass 100g falls from a tree because of gravitational attraction between the earth and the apple. If the magnitude of force exerted by the earth on the apple be F₁, and the magnitude of force exerted by the apple on the earth be F₂, then:

1. F₁ is very much greater than F₂
2. F₂ is very much greater than F₁
3. F₁ is only a little greater than F₂
4. F₁ and F₂ are exactly equal.

Water falls from a height of 60m at the rate of 15kg is  operate a turbine. The soosses due to frictional forces are 10% of energy. How much power is generated by the turbine? (Take, g = 10m/ s²)