Answer:
9
Explanation:
since the resistance is not changing
Answer:
Refraction
Explanation:
- Whenever there is a change in media through which light travels there is change in the speed of light due to which there is bending of light when there is change in the medium.
- When a ray of light passes from and optically denser medium to and optically rarer medium then it bends away from the normal to the interface and vice-versa.
As here the scuba driver is looking from an optically denser medium to an optically rarer medium the boy may appear nearer to the diver in position than is actually in the air.
Snell's law gives the relation between the angle of incidence and the angle of refraction as:

where
n = refractive index
i = angle of incidence
r = angle of refraction
Answer:

Explanation:
From the question we are told that
Distance b/w A&B 
Frequency 
Sound speed 
Generally the equation for wavelength is mathematically given as




Generally the destructive interference X is mathematically given by


Therefore the destructive interference is

Newtons first law of motion
object in motion stays in motion, object at rest stays at rest unless acted upon an unbalanced force