Physics Answers

Question 21 

An under-water swimmer cannot see very clearly even in absolutely clear water because of

Question 21 options:

A) 

Scattering of light in water

B) 

No option is correct

C) 

Reduction of speed of light in water

D) 

Change in the focal length of eye lens

E) 

Absorption of light in water

A bug flying at eye level is located 15 cm in front of a plane mirror. If you are 65 cm from the bug and looking into the mirror, find the distance between your eyes and the apparent position of the bug's image in the mirror.

Question 20 

Which of the following forms a virtual and erect image for all positions of the object?

Question 20 options:

A) 

No option is correct

B) 

Concave mirror

C) 

Convex mirror

D) 

Concave lens

E) 

Both (a) and (c)

Question 19 (2 points)

For a total internal reflection, which of the following is correct?

Question 19 options:

A) 

Light travels in air only

B) 

Light travels in water only

C) 

Light travels from rarer to denser medium

D) 

Light travels from denser to rarer medium

E) 

No option is correct

On the + y axis a laser is located at y = + 3.0 cm. The coordinates of a small target are x = + 12.0 cm and y = + 6.0 cm. The + x axis represents the edge-on view of a plane mirror. At what point on the + x axis should the laser be aimed in order for the laser light to hit the target after reflection?

An object is placed in front of spherical mirror, and the magnification of the system is m = -6. What does this number tell you about the image?

Question 19 (2 points)

For a total internal reflection, which of the following is correct?

Question 19 options:

A) 

Light travels in air only

B) 

Light travels in water only

C) 

Light travels from rarer to denser medium

D) 

Light travels from denser to rarer medium

E) 

No option is correct

Imagine that a motorist is travelling so fast that the yellow light (585 nm wavelength) from a traffic signal appears green (555 nm wavelength). Find the velocity of the motorist, assuming the positive direction is defined as moving closer to the light.

Unpolarized light with an intensity of 120 W falls on a polarizer and analyser. The angle between the transmission axes of the polarizer and analyser is 72°. What is the intensity of the light leaving the analyser, reaching the photocell?

Question 18 (5 points)

A concave mirror has a focal length of -27.0 cm. Find the magnification produced by the mirror when the object distance is 9.0 cm and 18.0 cm.

Question 18 options:

A) 

No option correct

B) 

0.750 and 0.600

C) 

0.850 and 0.500

D) 

0.950 and 0.800

E) 

0.650 and 0.700