Answer:
Newton's Second Law of Motion
Explanation:
According to Newton's second law of motion, the change in velocity of a body is directly proportional to the force applied on it. Velocity is a vector quantity. It measures the magnitude of the speed as well as its direction.
F = m a
where, F is the applied force, m is the mass and a is the acceleration.
It can also be expressed as:

where, p = mv ( momentum)
Answer:
15.Radiowave
16.laser is device that generates an intense beam of other electromagnetic radiation by emission of photons from excited atoms.
17.this is a laboratory instrument commonly used to display and analyse the waveformof electronic signals.
19. this is a space entirely devoid of matter.
Answer:

Explanation:
According to Coulomb's law, the magnitude of the force (F) between two objects with the same charge(+Q), separated a distance (d) apart, is defined as:

Here k is the Coulomb constant. The charge on each object is doubled, that is
:
