statement c would be correct I think.
Answer:
The acceleration of the object equals the gravitational acceleration. The mass, size, and shape of the object are not a factor in describing the motion of the object. So all objects, regardless of size or shape or weight, free fall with the same acceleration
Doppler effect is the compression or extension of a sound wave, which causes a change in its wavelength / frequency (and so its sound).
Explanation: It is defined as the effect produced by a moving source of waves in which there is an upward shift in frequency for observers, the source is moving towards and downward shift of frequency from which the source is moving away. used to tell if an object in space is moving toward or away from us.
Answer:
Give any two application for isotopes
Isotopes of iodine are used for radiotherapy in treatment of hyperthyroidism, cancer, etc.
Uranium, Radium, Polonium isotopes are used in atomic reactors.
Cobalt isotopes are used for irradiation of food products.