If $g$ is the acceleration due to gravity on the earth's surface,the gain in the potential energy of an object of mass $m$ raised from the surface of the earth to a height equal to the radius $R$ of the earth,is

The reading of a spring balance corresponds to $100 N$ while situated at the north pole and a body is kept on it. The weight record on the same scale if it is shifted to the equator, is $...........\,N$

(take, $g =10 m / s ^2$ and radius of the earth, $R =6.4 \times 10^3 m$ )

When an air bubble of radius $r$ rises from the bottom to the surface of a lake, its radius becomes $\frac{5r}{4}$. If the atmospheric pressure is equal to the pressure exerted by a $10 \ m$ height of water column, and the temperature remains constant while surface tension is neglected, what is the depth of the lake (in $m$)?

Which characteristic of living organisms ensures that the population size of each species remains limited?

Magnetic lines of force due to a bar magnet do not intersect because

If the bond length and dipole moment of a diatomic molecule are $1.25 \ \mathring{A}$ and $1.0 \ D$ respectively,what is the per cent ionic character of the bond?