Interactions at boundaries - Questions

Interactions at boundaries
































Light which strikes a mirror at a 30 degree angle of incidence will reflect at an angle to the perpendicular of

(A) 60 degrees.
(B) 90 degrees.
(C) 45 degrees.
(D) 30 degrees.

Questions --- What this question is about
102.1
































Light which strikes a mirror at a 30 degree angle of incidence will reflect at an angle to the perpendicular of

(A) 60 degrees. --- No.

Both angles are measured from the perpendicular.

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Questions --- What this question is about
102.1
































Light which strikes a mirror at a 30 degree angle of incidence will reflect at an angle to the perpendicular of

(B) 90 degrees. --- No.

That would make it parallel to the surface.

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Questions --- What this question is about
102.1
































Light which strikes a mirror at a 30 degree angle of incidence will reflect at an angle to the perpendicular of

(C) 45 degrees. --- No.

Angle of reflection = angle of incidence.

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Questions --- What this question is about
102.1
































Light which strikes a mirror at a 30 degree angle of incidence will reflect at an angle to the perpendicular of

(D) 30 degrees. --- Yes.

Angle of reflection = angle of incidence.

Check the other answers.
Questions --- What this question is about
102.1
































Which of the following surfaces would most likely be a diffuse reflector?

(A) Cotton cloth
(B) A water surface.
(C) A polished metal surface.
(D) A window pane.

Questions --- What this question is about
102.2































Which of the following surfaces would most likely be a diffuse reflector?

(A) Cotton cloth --- Yes.

It is a rough surface and will scatter light.

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Questions --- What this question is about
102.2
































Which of the following surfaces would most likely be a diffuse reflector?

(B) A water surface. --- No.

Usually that would be smooth and a specular reflector.

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Questions --- What this question is about
102.2
































Which of the following surfaces would most likely be a diffuse reflector?

(C) A polished metal surface. --- No.

That will give equal-angle reflections only.

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Questions --- What this question is about
102.2
































Which of the following surfaces would most likely be a diffuse reflector?

(D) A window pane. --- No.

What light reflects does so by the equal angle law.

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Questions --- What this question is about
102.2

































You are standing in a stream (up to your knees) and see a fish swimming by. If you wish to hit the fish with a spear, you should

(A) aim directly at where you see it.
(B) aim above where you see it.
(C) aim below where you see it.
(D) aim beside where you see it.

Questions --- What this question is about
102.3

































You are standing in a stream (up to your knees) and see a fish swimming by. If you wish to hit the fish with a spear, you should

(A) aim directly at where you see it.
No. --- Refraction at the surface shifts the image.

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Questions --- What this question is about
102.3

































You are standing in a stream (up to your knees) and see a fish swimming by. If you wish to hit the fish with a spear, you should

(B) aim above where you see it.
No. --- Light from the fish bends away from the normal.

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Questions --- What this question is about
102.3

































You are standing in a stream (up to your knees) and see a fish swimming by. If you wish to hit the fish with a spear, you should

(C) aim below where you see it.
Yes. --- The image is high because light bends away from the normal.

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Questions --- What this question is about
102.3

































You are standing in a stream (up to your knees) and see a fish swimming by. If you wish to hit the fish with a spear, you should

(D) aim beside where you see it.
No. --- The refracted ray is in the same plane as the incident and normal.

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Questions --- What this question is about
102.3

































The critical angle for a piece of glass is 42 degrees. In which of the following situations will light be 100% reflected?

(A) From the outside at a 45 degree angle of incidence.
(B) From the inside at a 45 degree angle of incidence.
(C) From the outside at a 40 degree angle of incidence.
(D) From the inside at a 40 degree angle of incidence.

Questions --- What this question is about
102.4

































The critical angle for a piece of glass is 42 degrees. In which of the following situations will light be 100% reflected?

(A) From the outside at a 45 degree angle of incidence.
No. --- Only light from the slower medium is reflected totally.

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Questions --- What this question is about
102.4

































The critical angle for a piece of glass is 42 degrees. In which of the following situations will light be 100% reflected?

(B) From the inside at a 45 degree angle of incidence.
Yes. --- Angle of incidence greater than the critical angle.

Check the other answers.
Questions --- What this question is about
102.4

































The critical angle for a piece of glass is 42 degrees. In which of the following situations will light be 100% reflected?

(C) From the outside at a 40 degree angle of incidence.
No. --- Only light from the slower medium is reflected totally.

Try again.
Questions --- What this question is about
102.4

































The critical angle for a piece of glass is 42 degrees. In which of the following situations will light be 100% reflected?

(D) From the inside at a 40 degree angle of incidence.
No. --- The angle of incidence must exceed the critical angle.

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Questions --- What this question is about
102.4