Test 3 Questions Flashcards
f
Positive:
Negative:
Positive: Concave Mirror
Negative: Convex/Diverging Mirror
do
Positive:
Negative:
Positive: Real Object
Negative: Virtual Object
di
Positive:
Negative:
Positive: Real Image
Negative: Virtual Image
m
Positive:
Negative:
Positive: Upright image
Negative: Inverted Image
All real images:
(a) are upright
(b) are inverted
(c) can appear on a screen
(d) cannot appear on a screen
(c) can appear on a screen
When an object is reflected in a plane mirror, the image is always
(a) real
(b) inverted
(c) enlarged
(d) left-right reversed
(d) left-right reversed
A dentist wants a small mirror that, when 2.20 cm from a tooth, will produce a 4.5 X upright image. What kind of mirror must be used and what must its radius of curvature be?
m=hi/ho=-di/do
4.5=-di/(2.20 cm), which gives di=-9.90 cm
The focal length is given by
1/do+1/di=1/f, i.e., 1/(2.20cm) +1/(-9.90 cm)=1/f, which yields f=2.83 cm
Focal length is positive, the mirror is concave with a radius of r=2f=5.7 cm
A light ray enters one medium from another along the normal. The angle of reflection
(a) is 0°
(b) is 90°
(c) equals the critical angle
(d) depends on the indexes of refraction of the two media.
(a) is 0°
When a beam of light enters one medium from another, a quantity that never changes is its
(a) direction
(b) speed
(c) frequency
(d) wavelength
(c) frequency
The index of refraction of a materials medium
(a) is always less than 1
(b) is always equal to 1
(c) is always equal to, or greater than 1
(d) may be less than, equal to, or greater than 1
(c) is always equal to, or greater than 1
A beam of parallel light enters a block of ice an angle of incidence of 30o. What is the angle refraction in the ice? (nair=1 and nice=1.31)
sinr=n1/ n2sini=1/1.31sin30o=0.382, thus, r=22o
When you look down into a swimming pool, are you likely to underestimate or overestimate its depth?
The pool appears shallower than it is.
A material has an index of refraction that increases continuously from top to bottom. Of the three paths shown in the figure below, which path will a light ray follow as it passes through the material?
When light goes from one material into one having a higher index of refraction, it refracts toward the normal line of the boundary between the two materials. If, as the light travels through the new material, the index of refraction continues to increase, the light ray will refract more and more
toward the normal line.!
As light travels from vacuum (n = 1) to a medium such as glass (n > 1), which of the following properties remains the same:
(a) wavelength
(b) wave speed
(c) frequency
(c). Both the wave speed and the wavelength decrease as the index of refraction increases. The frequency is
unchanged.
In a vacuum, the speed of an electromagnetic wave
(a) depends on its frequency
(b) depends on its wavelength
(c) depends on its electric and magnetic fields
(d) is a universal constant
(d) is a universal constant
Which one of the following statements concerning electromagnetic waves is false?
(a) Electromagnetic waves are longitudinal waves.
(b) Electromagnetic waves transfer energy through space.
(c) The existence of electromagnetic waves was predicted by Maxwell.
(d) Electromagnetic waves can propagate through a material substance.
(e) Electromagnetic waves do not require a physical medium
(a) Electromagnetic waves are longitudinal waves.
Which one of the following will not generate electromagnetic waves or pulses?
(a) a steady direct current
(b) an accelerating electron
(c) a proton in simple harmonic motion
(d) an alternating current
(e) charged particles traveling in a circular path in a mass spectrometer
(a) a steady direct current
Complete the following sentence: When electrons from a heated filament accelerate through vacuum toward a positive plate,
(a) only an electric field will be produced.
(b) only a magnetic field will be produced.
(c) electromagnetic waves will be produced.
(d) longitudinal waves will be produced.
(e) neither electric nor magnetic fields will be produced.
(c) electromagnetic waves will be produced.
Which one of the following types of wave is intrinsically different from the other four?
(a) radio waves
(b) gamma rays
(c) visible light
(d) sound waves
(e) ultraviolet radiation
(d) sound waves
Which one of the following statements concerning electromagnetic waves is false? (a) Electromagnetic waves carry energy.
(b) X-rays have longer wavelengths than radio waves.
(c) In vacuum, all electromagnetic waves travel at the same speed.
(d) Lower frequency electromagnetic waves can be produced by oscillating circuits.
(e) They consist of mutually perpendicular electric and magnetic fields that oscillate perpendicular to the direction of propagation.
(b) X-rays have longer wavelengths than radio waves.
Which one of the following statements concerning the wavelength of an electromagnetic wave in a vacuum is true?
(a) The wavelength is independent of the speed of the wave for a fixed frequency.
(b) The wavelength is inversely proportional to the speed of the wave.
(c) The wavelength is the same for all types of electromagnetic waves.
(d) The wavelength is directly proportional to the frequency of the wave.
(e) The wavelength is inversely proportional to the frequency of the wave.
(e) The wavelength is inversely proportional to the frequency of the wave.
Complete the following sentence: The various colors of visible light differ in
(a) frequency only.
(b) frequency and wavelength.
(c) wavelength only.
(d) frequency and their speed in a vacuum.
(e) their speeds in a vacuum.
(b) frequency and wavelength.
A cellular telephone transmits electromagnetic waves at a frequency of 935 MHz. What is the wavelength of these waves?
(a) 0.0106 m
(b) 0.321 m
(c) 0.642 m
(d) 1.22 m
(e) 2.40 m
(b) 0.321 m
An average distance between the surface of the earth and the surface of the sun is 1.49x1011 m. How much time, in minutes, does it take for light leaving the surface of the sun to reach the earth?
(a) zero minutes
(b) 2.9x10–3 min
(c) 8.3 min
(d) 74 min
(e) 500 min
(c) 8.3 min