Sample Exam III

  1. The largest frequency of visible light corresponds to the color_________.

a. blue      b. green      c.  red        d. violet             e. yellow

  2. A 6.5 feet tall, beautiful lady wants to buy a mirror that is tall enough so that she can see her full figure in
the mirror. What is the minimum height of such a mirror?

  a. 6 ft   b.  3.25 ft     c.  4.25 ft    d.  3 ft

  3. The term coherent sources refers to sources whose light has

  a. the same frequency.              b. the same amplitude  

c. the same frequency and the constant phase relationship.

d. different frequencies and a constant phase relationship

  4. Light is incident on an air-water interface at an angle of 30 degree to the normal. What angle does the
refracted ray make with the normal?

a. 19 deg.      b. 22 deg.      c. 25 deg.      d. 90 deg.

  5. An object is placed 40.0 cm in front of a convex mirror. The image appears 15 cm behind the mirror.
What is the focal length of the mirror?

  a. 11 cm   b. 24 cm   c. -24 cm    d. -11 cm

  6. A convex spherical mirror has a radius of curvature of 150 cm. What is its focal length?

(a)    0.50 m  (b) -0.75 m  (c) 2 m  (d) -1 m

  7. Total internal reflection happens when a light ray passes from

(a)    less dense medium to more dense medium

(b)   more dense medium to less dense medium

(c)    high medium to high medium

(d)   less dense to less dense medium

1. What is the speed of light in the material whose index of refraction is 2.54? What would be
frequency in the new material?

  2. An object 3.0 cm high is placed 20.0 cm from a convex mirror with a focal length of 8.0 cm.
Find (a) the position of the final image and (b) the magnification of the mirror.

  3. Light reflected from a fish strikes the surface of the water at an angle of 35 degrees to the normal.
What is the angle of refraction of the light into the air?

  4. Relative to the central fringe, what is the position on a screen located 2.5 m away of the fourth order
fringe in a double slit arrangement (d= 0.058 mm) when the slits are illuminated with l = 480 nm light?

  5 A clear spring has white shells on its bottom, which appear to the occupants of a boat to be
only 45.0 ft. below. What is the actual depth of the spring?