Optics MCQ with Answers

126) Light traveling in air is incident on the surface of a block of plastic at an angle of 62.7^??to the normal and is bent so that it makes a 48.1^??angle with the normal in the plastic. Find the speed of light in the plastic

Answer is:

2.51??10⁸ms^?1

Explanation:

use snell's law

127) The critical angle for total internal reflection at a liquid?air interface is 42.5^??If a ray of light traveling in the liquid has an angle of incidence at the interface of 35^??what angle does the refracted ray in the air make with the normal?

Answer is:

58.1^?

Explanation:

Angle of reflection = angle of incidence (B) Use Snell's law. n1/n2 = sin(theta1)/sin(theta2) But in order to use snell's law, you need to get the ratio of n's first. You can do that, though, using the fact that light incoming at the critical angle refracts at 90 degrees. n1/n2 = sin(critical angle)/sin(90 degrees)= sin (critical angle) Therefore, for your answer to part (B) sin (refracted angle) = sin (incident angle)sin(critical angle).

128) The critical angle for total internal reflection at a liquid°air interface is 42.5^°°If a ray of light traveling in air has an angle of incidence at the interface of 35^°°what angle does the refracted ray in the liquid make with the normal?

Answer is:

22.8^°

Explanation:

Angle of reflection = angle of incidence (B) Use Snell's law. n1/n2 = sin(theta1)/sin(theta2) But in order to use snell's law, you need to get the ratio of n's first. You can do that, though, using the fact that light incoming at the critical angle refracts at 90 degrees. n1/n2 = sin(critical angle)/sin(90 degrees)= sin (critical angle) Therefore, for your answer to part (B) sin (refracted angle) = sin (incident angle)sin(critical angle).

129) Unpolarized light with intensity I0 is incident on two polarizing filters. The axis of the first filter makes an angle of 60.0^??with the vertical, and the axis of the second filter is horizontal. What is the intensity of the light after it has passed through the second filter

Answer is:

0.375?I₀

Explanation:

use malus law I = I_ocos^2/theta

130) A parallel beam of unpolarized light in air is incident at an angle of 54.5I₀?(with respect to the normal) on a plane glass surface.The reflected beam is completely linearly polarized. What is the refractive index of the glass?

Answer is:

1.4

Explanation:

use malus law I = I_ocos^2/theta

126) Light traveling in air is incident on the surface of a block of plastic at an angle of 62.7??to the normal and is bent so that it makes a 48.1??angle with the normal in the plastic. Find the speed of light in the plastic

2.51??108ms?1

127) The critical angle for total internal reflection at a liquid?air interface is 42.5??If a ray of light traveling in the liquid has an angle of incidence at the interface of 35??what angle does the refracted ray in the air make with the normal?

58.1?

128) The critical angle for total internal reflection at a liquid°air interface is 42.5°°If a ray of light traveling in air has an angle of incidence at the interface of 35°°what angle does the refracted ray in the liquid make with the normal?

22.8°

129) Unpolarized light with intensity I0 is incident on two polarizing filters. The axis of the first filter makes an angle of 60.0??with the vertical, and the axis of the second filter is horizontal. What is the intensity of the light after it has passed through the second filter

0.375?I0

130) A parallel beam of unpolarized light in air is incident at an angle of 54.5I0?(with respect to the normal) on a plane glass surface.The reflected beam is completely linearly polarized. What is the refractive index of the glass?

1.4

126) Light traveling in air is incident on the surface of a block of plastic at an angle of 62.7^??to the normal and is bent so that it makes a 48.1^??angle with the normal in the plastic. Find the speed of light in the plastic

2.51??10⁸ms^?1

127) The critical angle for total internal reflection at a liquid?air interface is 42.5^??If a ray of light traveling in the liquid has an angle of incidence at the interface of 35^??what angle does the refracted ray in the air make with the normal?

58.1^?

128) The critical angle for total internal reflection at a liquid°air interface is 42.5^°°If a ray of light traveling in air has an angle of incidence at the interface of 35^°°what angle does the refracted ray in the liquid make with the normal?

22.8^°

129) Unpolarized light with intensity I0 is incident on two polarizing filters. The axis of the first filter makes an angle of 60.0^??with the vertical, and the axis of the second filter is horizontal. What is the intensity of the light after it has passed through the second filter

0.375?I₀

130) A parallel beam of unpolarized light in air is incident at an angle of 54.5I₀?(with respect to the normal) on a plane glass surface.The reflected beam is completely linearly polarized. What is the refractive index of the glass?