Answer:
One when it enters the glass slab from air and second time when it enters the air through glass slab. When light rays travelling through air enters glass slab, they get refracted and bend towards the normal. Now the direction of refracted ray changes again when it comes out of the glass slab into air.
Answer:
The current of the solenoid is 0.0129 A.
Explanation:
The movement of the electron within the solenoid in a circle is produced by equaling the magnetic force and the centripetal force, as follows:


Where:
I: is the current
m: is the electron's mass = 9.1x10⁺³¹ kg
v: is the electron's speed = 3.0x10⁵ m/s
μ₀: is the permeability magnetic = 4πx10⁻⁷ T.m/A
n: is the number of turns per unit length = 35/cm
r: is the radius of the circle = 3.0 cm
e: is the electron's charge = 1.6x10⁻¹⁹ C
Therefore, the current of the solenoid is 0.0129 A.
I hope it helps you!
The correct answer to this question is D