Download Mid term Exam Review ch 15 16 17 18 w

Mid term Exam Review
Multiple Choice
Identify the choice that best completes the statement or answers the question.
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1. A sound wave in air has a frequency of 680 cycles per second. What is the approximate wavelength of the
sound wave?
a. 680 m
c. 340 m
b. 0.5 m
d. 20 m
2. If a transverse wave is moving from right to left, the individual particles in the medium are moving
a. right to left.
c. up and down.
b. left to right.
d. None of the above
3. _____ is the inverse of period.
a. Wavelength
c. Frequency
b. Crest
d. Amplitude
4. Waves travel quickly in a _____ because the molecules are closely packed and physically bonded together.
a. liquid
c. solid
b. gas
d. None of the above
5. Water waves
a. transport energy and water.
c. transport water but not energy.
b. transport energy but not water.
d. are not mechanical waves.
6. A wave x meters long has a speed of y meters per second. The frequency of the wave is
a. x/y.
c. yx.
b. y/x.
d. y + x.
7. A wave with a frequency of 0.5 Hz and a speed of 10 m/s has a wavelength of
a. 50 m.
c. 20 m.
b. 0.5 m.
d. 0.2 m.
8. The color that an object appears to be depends on the
a. angle at which visible light is reflected off the object.
b. use of additive rather than subtractive colors.
c. wavelengths of visible light that reaches your eyes.
d. speed with which visible light reaches it.
9. Which statement about the lens of the eye is incorrect?
a. It is made of fibers.
c. It has a fixed curvature.
b. It is behind the pupil.
d. It focuses light rays on the retina.
10. Which of these affects the speed of sound?
a. loudness of the sound
c. temperature
b. resonance
d. direction of the wave
11. Because its molecules are far apart, sound waves will travel slowly through
a. cold air.
c. iron.
b. water.
d. copper.
____ 12. The rate at which energy flows through a given space describes light
a. resonance.
c. intensity.
b. pitch.
d. interference.
____ 13. Light rays reflecting off a smooth surface reflect
a. in one new direction.
c. in random directions.
b. in the initial direction.
d. None of the above
____ 14. Light rays reflecting off a rough surface reflect
a. diffusely.
c. at all angles.
b. at a single angle.
d. None of the above
____ 15. Reflection of light into random directions is called
a. diffuse reflection.
c. the angle of reflection.
b. the law of reflection.
d. the reflective ray.
____ 16. When light moves from a material in which its speed is higher to one in which its speed is lower, the ray is
a. bent away from the normal.
c. converged.
b. bent toward the normal.
d. diverged.
____ 17. The particle model of light explains how light can
a. travel through empty space without a medium.
b. refract when it passes through a lens.
c. be reflected off a mirror.
d. diffract when it passes through a normal opening.
____ 18. When you look at an orange, you see the color orange because the fruit
a. reflects orange light and absorbs other colors.
b. absorbs orange light and reflects other colors.
c. reflects red and yellow light only.
d. absorbs red and yellow light only.
____ 19. Which property of light is not explained by the wave model of light?
a. Light produces interference patterns.
b. Light is diffracted when it passes through a narrow opening.
c. Blue light can knock electrons off a plate but red light cannot.
d. Light reflects when it meets a mirror, but it refracts when it passes through a lens.
____ 20. The brightness of a light bulb is determined by its filament’s
a. voltage.
c. watts.
b. amperes.
d. resistance.
____ 21. Positive charges _____ one another.
a. attract
c. repel
b. cancel
d. join
____ 22. Which of the following is a negatively charged particle?
a. proton
c. coulomb
b. electron
d. neutron
____ 23. The SI unit of resistance is the
a. volt.
c. ohm.
b. ampere.
d. joule.
____ 24. If a lamp is measured to have a resistance of 120  when it operates at a power of 1.00  102 W, what is the
potential difference across the lamp?
a. 110 V
c. 0.913 V
b. 120 V
d. 220 V
____ 25. When there is an equal amount of positive and negative charges on an object, the object is
a. positively charged.
c. neutral.
b. negatively charged.
d. supercharged.
____ 26. When compared to a –2 charge, there are
a. an equal number of field lines pointing inward toward a +4 charge.
b. twice as many field lines pointing inward toward a +4 charge.
c. twice as many field lines pointing outward from a +4 charge.
d. half as many field lines pointing outward from a +4 charge.
____ 27. Current is the rate at which charges move through a(n)
a. conductor.
c. voltage.
b. insulator.
d. joule.
____ 28. A device that protects a circuit from current overload is called a
a. resistor.
c. circuit breaker.
b. capacitor.
d. closed circuit.
____ 29. What happens to the overall resistance of a circuit when too many appliances are connected across a 120-V
outlet?
a. Resistance is increased.
c. Resistance is decreased.
b. Resistance stays the same.
d. Resistance is zero.
____ 30. The strength of a magnetic field created by current in a wire can be increased by
a. using shorter wire.
c. using longer wire.
b. decreasing the current in the wire.
d. wrapping the wire into a coil.
____ 31. Pushing a loop of wire through a magnetic field requires work. The greater the magnetic field,
a. the stronger the force required to push the loop through the magnetic field.
b. the less the force required to push the loop through the magnetic field.
c. the less will be the electromagnetic induction.
d. the more the loop will rotate.
____ 32. Generators convert
a. mechanical energy to electrical energy.
b. electrical energy to mechanical energy.
c. chemical energy to electrical energy.
d. electrical energy to chemical energy.
____ 33. When a wire is moving parallel to a magnetic field,
a. no current is induced in the wire.
b. maximum current is induced in the wire.
c. the same current is induced as if it were perpendicular to the field.
d. an alternating current is induced.
____ 34. Increasing the number of coils in a solenoid or an electromagnet results in a _____ magnetic field.
a. weaker
c. perpendicular
b. stronger
d. parallel
____ 35. In an AC generator, the magnitude of the current produced
a. depends on the orientation of the loop in a magnetic field.
b. is zero when the loop is perpendicular to the magnetic field.
c. varies with time.
d. All of the above
____ 36. Light travels as
a. electrical waves.
c. electromagnetic waves.
b. magnetic waves.
d. electrochemical waves.
____ 37. Like magnetic poles always
a. repel each other.
c. point toward the south pole.
b. attract each other.
d. point toward the north pole.
____ 38. An example of a naturally occurring magnetic rock is
a. lodestone.
c. limestone.
b. soapstone.
d. peastone.
____ 39. When a magnetic field is applied near iron, the iron’s domains
a. scatter and decrease the iron’s magnetic field.
b. align and increase the iron’s magnetic field.
c. scatter and increase the iron’s magnetic field.
d. align and decrease the iron’s magnetic field.
____ 40. Both electric and magnetic fields in an electromagnetic wave are
a. perpendicular to the direction that the wave travels.
b. parallel to the direction that the wave travels.
c. opposite the direction that the wave travels.
d. tangential to the direction that the wave travels.
Completion
Complete each statement.
41. The ____________________ is the time required for one full wavelength to pass a certain point.
42. The ____________________ is the number of vibrations that occur in a given time interval.
43. A wave that causes the particles of the medium to vibrate perpendicularly to the direction the wave travels is
called a(n) ______________________________.
44. The lowest point of a wave is called the ____________________.
45. Resonance occurs when the vibration of one object causes another object to vibrate at a(n)
______________________________.
46. Sonograms are possible because some ultrasound waves are ____________________ when they pass from
one type of material to another.
47. The amount of light that illuminates a given surface area is referred to as ____________________.
48. In a vacuum, all light travels at the same speed, which is ____________________.
49. The electromagnetic waves with the highest energy are classified as _________________________.
50. The image that you see in a mirror that results from the apparent path of light rays is called a(n)
____________________ image.
51. In a(n) ____________________ image, light rays really exist at the point where the image appears.
52. Light may bend when it changes mediums because ______________________________ is different in each
medium.
53. Light first enters the eye through a transparent tissue called the ____________________.
54. The cones in the eye allow ____________________ vision, and the rods are more sensitive to
____________________ light.
55. A transparent object that can separate white light into different colors is called a(n) ____________________.
56. The effect in which light separates into different colors because of differences in speed is called
____________________.
57. The three small bones in your middle ear are the ____________________, the ____________________, and
the ____________________.
58. Radio waves, microwaves, and infrared waves make up a part of the ______________________________.
59. When you look into a flat mirror, you see a(n) ____________________ image.
60. Reflection of light in random directions is called ______________________________.
Short Answer
61. Why do electrical devices feel warm after they have been on for a period of time?
62. Is a current flowing in the schematic diagram below? Explain your answer.
63. What is Faraday’s law?
64. What are two ways to increase the strength of the magnetic field of a solenoid?
65. What do magnetic force, gravitational force, and force between electric charges have in common?
Problem
66. There is a potential difference of 13 V across a resistor with 1.4 A of current in it. What is the resistance of
the resistor?
67. A hair dryer draws 11 A when it is connected to 120 V. If electrical energy costs $0.09/kWh, what is the cost
of using the hair dryer for exactly 15 minutes?
68. If a 75 W light bulb operates at a voltage of 120 V, what is the current in the bulb?
69. A resistor has a resistance of 1.8 . How much current is in the resistor if there is a potential difference of 3.0
V across the resistor?
70. A 180- resistor has 0.10 A of current in it. What is the potential difference across the resistor?