Give two characteristics of gravitational force.

what is gravitational force ?

What is crystal lattice? Write two characteristics of crystal lattice.

what is the range of gravitational force ?

Give two characteristics of electromagnetic waves. Write the expression for the velocity of electromagnetic waves in terms of the permitivity and permeability of the medium.

Mention any two characteristics of chemisorption.

Name and write two characteristics of the following two crystal defects mentioned in the figure.

A body weighs 63 N on the surface of the earth. What is the gravitational force on it due to the earth at a height equal to half the radius of the earth?

The earth and the moon are attracted to each other by gravitational force. Does the earth attract the moon with a force that is greater or smaller or the same as the force with which the moon attracts the earth? Why?