Science Bowl Practice Questions

Physics - 9

51.

Short Answer: The focal length of a concave mirror is 2 meters. An object is positioned 8 meters in
front of the mirror. Where is the image of this object formed?

ANSWER: 8/3 METER or 2.66 METERS IN FRONT OF THE MIRROR

52.

Short Answer: A converging thin lens has a focal length of 27 centimeters. An object is placed 9
centimeters from the lens. Where is the image of this object formed?

ANSWER: -13.5 CENTIMETERS or 13.5 CENTIMETERS ON THE OBJECT SIDE
OF THE LENS

53.

Short Answer: In Bohr's theory of the atom, what force was responsible for holding the electrons in
their orbit?

ANSWER: COULOMB FORCE or THE FORCE OF ATTRACTION BETWEEN THE PROTON
(NUCLEUS) AND THE ELECTRON

54.

Short Answer: Davisson and Germer scattered electrons from a crystal of nickel. The scattered
electrons formed a strong diffraction pattern. What important conclusion was drawn from this
experiment?

ANSWER: ELECTRONS ACTED LIKE WAVES

55.

Short Answer: The speed at which a wave propagates down a string is 300 meters per second. If the
frequency of this wave is 150 Hertz, what is the wavelength of this wave?

ANSWER: 2 METERS

56.

Multiple Choice: A standing wave is formed on a tightly stretched string. The distance between a node
and an antinode is:

w) 1/8 wavelength
x) 1/4 wavelength
y) 1/2 wavelength
z) 1 wavelength

ANSWER: X -- 1/4 WAVELENGTH

57.

Multiple Choice: When a physical property such as charge exists in discrete "packets" rather than in
continuous amounts, the property is said to be:

w) discontinuous
x) abrupt
y) quantized
z) noncontinuous

ANSWER: Y – QUANTIZED

58.

Short Answer: Assume a ray of light is incident on a smooth reflecting surface at an angle of incidence
of 15 degrees to the normal. What is the angle between the incident ray and the reflected ray?

ANSWER: 30 DEGREES

59.

Short Answer: The focal length of a concave spherical mirror is equal to 1 meter. What is the radius of
curvature of this mirror?

ANSWER: 2 METERS

60.

Short Answer: A virtual image can be formed by one or more of the following single mirrors? Identify
them.