Given below are some examples of wave motion. State in each case if the wave motion is transverse , longitudinal or a combination of both:
(a) Motion of a kink in a longitudinal spring produced by displacing one end of the spring sideways.
(b) Waves produced in a cylinder containing a liquid by moving its piston back and forth.
(c) Waves produced by a motorboat sailing in water.
(d) Ultrasonoic waves in air produced by a vibrating quartz crystal.

Explanation

(a) Transverse and longitudinal
(b) Longitudinal
(c ) Transverse and longitudinal
(d) Longitudinal