Answer:

Explanation:
The relationship between the refractive index and the critical angle is given as follows:

where,
η = refractive index = 1.67
θc = critical angle =?
Therefore,


Answer:True
Explanation:
Buoyant force is the net upward force, that affect on the object in a fluid
Answer:
The magnetic flux through a loop is zero when the B field is perpendicular to the plane of the loop.
Explanation:
Magnetic flux are also known as the magnetic line of force surrounding a bar magnetic in a magnetic field.
It is expressed mathematically as
Φ = B A cos(θ) where
Φ is the magnetic flux
B is the magnetic field strength
A is the area
θ is the angle that the magnetic field make with the plane of the loop
If B is acting perpendicular to the plane of the loop, this means that θ = 90°
Magnetic flux Φ = BA cos90°
Since cos90° = 0
Φ = BA ×0
Φ = 0
This shows that the magnetic flux is zero when the magnetic field strength B is perpendicular to the plane of the loop.