Question

# Friction arises due to the interlocking of hills and ________ present in a body.A. MountainsB. HolesC. ValleysD. None

Hint: Friction is a contact force. It tries to oppose relative motion between two surfaces. It arises when the uneven surfaces of two materials get interlocked with each other due to the interlocking of the tiny bulging out and caving in parts of the uneven surfaces.

Note: The frictional force depends on the coefficient of friction$\left( \mu \right)$. This is a measure of the unevenness and interlocking ability of the surfaces. A surface with a higher coefficient of friction is generally rougher and interlocks with other surfaces to a greater extent, thus producing a stronger frictional force.