Answer:
therefore critical angle c= 69.79°
Explanation:
Canola oil is less dense than water, so it floats over water.
Given 
which is higher than that of water
refractive index of water 
to calculate critical angle of light going from the oil into water
we know that

now putting values we get

c= 
c=69.79°
therefore critical angle c= 69.79°
Answer:
The acceleration is about 9.8 m/s2 (down) when the ball is falling.
Explanation:
The ball at maximum height has velocity zero
t = Time taken
u = Initial velocity
v = Final velocity
s = Displacement
a = Acceleration due to gravity = 9.8 m/s² (positive downward and negative upward)

The accleration 9.8 m/s² will always be acting on the body in opposite direction when the body is going up and in the same direction when the body is going down. The acceleration on the body will never be zero
The resultant force is 5N.So the box moves to right with constant acceleration.
electromagnetic spectrum is consisting of many frequency range which is from gamma rays to radio waves
they are of various wavelength and different energy levels
minimum wavelength will occurs at Gamma rays
and maximum wavelength at Radio waves
the list of increasing order of wavelength is as following
Gamma rays < X rays < Ultraviolet < Visible Light < Infrared Waves < Radio Waves
so least to maximum order is
1. Gamma rays
2. X rays
3 Ultraviolet
4 Visible light
5 Infrared waves
6 Radio waves