Which of the following statements about the gravitational constant is true?

The gravitational force of the Earth on a ball is $10 \mathrm{N}$ then the gravitational force of attraction of the ball on the earth is _____.

If the distance between the two given bodies is halved, then the force of attraction between them

A piece of paper and a cricket ball is dropped from a particular height. The piece of paper has taken a long time to reach the ground than the cricket ball because

A ball is dropped from a particular height, the velocity acquired by it is,

The height of the mercury column of a barometer at sea level is _____.

The change in the density of sea water is due to 

Write the following steps in a sequence in the construction of a barometer.

(A) Fill the glass tube with pure and dry mercury carefully so that no bubbles are trapped inside.

(B) Place the tube inverted in a trough containing mercury and remove the thumb.

(C) Take a glass tube closed at one end and of a narrow uniform bore of diameter $1 \mathrm{cm}$ and of length $1 \mathrm{m}$.

(D) Cover the open end with the thumb.