Natural Resources — Science STD 9 — Question

 What is the cause of buoyant force?

Why does water have higher boiling point than alcohol? At what temperature in Kelvin, it can be changed into solid state and into vapours?

Define gram molecular mass of a substance. How much is the gram molecular mass of oxygen?

Name the following:

1. Multinucleate muscle fibre.
2. Spindle shape muscle fibre.

How many moles of calcium carbonate (CaCO₃) are present in 10g of the substance?
(Ca = 40u; C = 12u; O = 16u)

Calculate the molecular masses of the following compounds:

1. Hydrogen sulphide, H₂S
2. Carbon disulphide, CS₂

What is Brownian motion? Draw a diagram to show the movement of a particle (like a pollen grain) during Brownian motion.

Give one example of an Indian and foreign poultry breed which when crossed produce an improved variety. List any one desirable trait expected from such cross breeding.

The values of g at six distances A, B, C, D, E and F from the surface of the earth are found to be 3.08m/s², 9.2.3m/s², 0.57m/s², 7.34m/s², 0.30m/s² and 1.49m/s², respectively.

1. Arrange these values of g according to the increasing distances from the surface of the earth (keeping the value of g nearest to the surface of the earth first).
2. If the value of distance F be 10000km from the surface of the earth, state whether this distance is deep inside the earth or high up in the sky. Give reason for your answer.

What is the significance of the formula H₂O?