Answer:
26.6°
Explanation:
refractive index of diamond, n = 2.23
When a ray of light passes from denser medium to the rarer medium and refracts at an angle of 90 degree from the normal of the surface, such angle of incidence in the denser medium is called the critical angle.
By the Snell's law

For critical angle, angle of incidence is critical angle, i = θc and angle of refraction, r = 90
So,
Sin θc / Sin 90 = 1 / 2.23
Sin θc = 0.448
θc = 26.6°
Thus, the critical angle is 26.6°.
Kinetic energy= .5 x m x v^2
KE=.5 x 4.2 x 3.85^2
KE=31.13
Answer:

Explanation:
The electric flux through a certain surface is given by (for a uniform field):

where:
E is the magnitude of the electric field
A is the area of the surface
is the angle between the direction of the field and of the normal to the surface
In this problem, we have:
is the electric field
L = 2.0 m is the side of the sheet, so the area is

, since the electric field is perpendicular to the surface
Therefore, the electric flux is

Answer:
Explanation:
Initial angular velocity ω₀ = 151 x 2π / 60
= 15.8 rad /s
final velocity = 0
Angular deceleration α = 2.23 rad / s
ω² = ω₀² - 2 α θ
0 = 15.8² - 2 x 2.23 θ
= 55.99 rad
one revolution = 2π radian
55.99 radian = 55.99 / 2 π no of terns
= 9 approx .