Explain how to change the pitch of the sound produced by a violin string when it is plucked or rubbed with the bow.

Sound is produced by moving the bow over the string or by plucking it with the right hand. Pitch alterations are achieved by pressing down the string with the fingertips of the left hand on the fingerboard. This shortens the vibrating portion of the string and raises the pitch

Explanation:

convex lenses are thicker at the middle. rays of light that pass through the lens are brought closer together (they converge). a convex lens is a converging lens. when parallel rays of light pass through a convex lens the refracted rays converge at one point called the principal focus.