Answer:
(a) 
(b) 
Explanation:
Given data
Distance r₁=50 m
Distance r₂=2 m
Intensity I₂=2.0 W/m²
To find
(a) The Sound Intensity I₁
(b) The Sound Intensity level β
Solution
For (a) the Sound Intensity I₁

For (b) the Sound Intensity level β
The Sound Intensity level β is calculated as follow

Explanation:
The refraction is the change in the direction of light while travelling from the one medium to another due to having different speeds in different mediums.
To determine how much light gets refracted, it depends on the density of substance and the wavelength and the angle at which light enters the substance.
Light travels more slowly in denser medium than the rarer medium. The refractive index of glass is more than water or air. Light gets refracted more in this. When the light travels from rarer to denser then the light will get bend towards the normal. When the light travels from denser to rarer then the light will get bend away from the normal.
Glass is more denser than air or water. Water is more denser than the air. When light travels from air to glass then the light gets bends towards the normal. When the light travels from glass to the air then light gets bends away from the normal.
Therefore, the light gets refracted more in the glass than air to water.
Answer:
A and C
Explanation:
Both have mass and are in motion
Axis labels. We don’t know what is being compared with the data
The fundamental mode of vibration of a wave is defined as that which has the LOWEST frequency