PHY 102 Week 4 Exam: Waves, Optics, Electricity &
Magnetism Actual Exam 2026/2027 – Complete
Questions and Answers with Detailed Rationales –
Pass Guaranteed – A+ Graded
Section 1: Waves & Sound
Q1: You are watching ocean waves roll onto the beach. You notice that the distance
between the crest of one wave and the crest of the next is 4 meters. If 10 waves pass
you every minute, what is the speed of the waves?
A. 0.4 m/s
B. 0.67 m/s
C. 2.5 m/s
D. 40 m/s
Correct Answer: B
Rationale: The best answer is B because you first find the frequency (10 waves/60
seconds = 0.167 Hz) and then use the wave speed equation v = fλ, which gives 0.167 ×
4 = 0.667 m/s.
Q2: A sound wave is traveling through the air. Which of the following statements
correctly describes the nature of this wave?
A. It is a transverse wave because the air particles move parallel to the direction of
wave propagation.
B. It is a longitudinal wave because the air particles oscillate back and forth parallel to
the direction the wave travels.
C. It is a transverse wave because it can travel through a vacuum.
D. It is a longitudinal wave because the air particles move up and down perpendicular to
the wave direction.
Correct Answer: B
Rationale: This choice is correct because sound waves in air are mechanical
longitudinal waves, meaning the particles of the medium (air) vibrate parallel to the
direction of the wave's energy transport.
Q3: [MANDATORY SCENARIO] You are standing on a train platform waiting for your
ride. Suddenly, you hear a train approaching, and the pitch of its horn sounds high. As
the train passes you and moves away, the pitch of the horn drops noticeably. Which
physical phenomenon best explains this change in pitch?
, A. Diffraction
B. Refraction
C. The Doppler Effect
D. Resonance
Correct Answer: C
Rationale: This matches the physics principle known as the Doppler Effect, which
describes the change in frequency (and pitch) of a wave caused by the relative motion
between the source of the wave and the observer.
Q4: In a physics lab, a student creates a standing wave in a string fixed at both ends.
The student observes points along the string that appear to be perfectly still. What are
these points called?
A. Antinodes
B. Nodes
C. Crests
D. Troughs
Correct Answer: B
Rationale: The best answer is B because nodes are the points in a standing wave
where destructive interference is always maximum, resulting in zero amplitude or no
movement.
Q5: A guitar string is plucked and vibrates at a frequency of 440 Hz. If the length of the
string is halved while keeping the tension constant, what will happen to the fundamental
frequency of the string?
A. It will decrease to 220 Hz.
B. It will remain at 440 Hz.
C. It will increase to 880 Hz.
D. It will become zero because the string is too short.
Correct Answer: C
Rationale: This choice is correct because the frequency of a vibrating string is inversely
proportional to its length; halving the length doubles the frequency (440 Hz × 2 = 880
Hz).
Q6: Which of the following electromagnetic waves has the shortest wavelength?
A. Radio waves
B. Microwaves
C. Visible light
D. Gamma rays
Correct Answer: D
Magnetism Actual Exam 2026/2027 – Complete
Questions and Answers with Detailed Rationales –
Pass Guaranteed – A+ Graded
Section 1: Waves & Sound
Q1: You are watching ocean waves roll onto the beach. You notice that the distance
between the crest of one wave and the crest of the next is 4 meters. If 10 waves pass
you every minute, what is the speed of the waves?
A. 0.4 m/s
B. 0.67 m/s
C. 2.5 m/s
D. 40 m/s
Correct Answer: B
Rationale: The best answer is B because you first find the frequency (10 waves/60
seconds = 0.167 Hz) and then use the wave speed equation v = fλ, which gives 0.167 ×
4 = 0.667 m/s.
Q2: A sound wave is traveling through the air. Which of the following statements
correctly describes the nature of this wave?
A. It is a transverse wave because the air particles move parallel to the direction of
wave propagation.
B. It is a longitudinal wave because the air particles oscillate back and forth parallel to
the direction the wave travels.
C. It is a transverse wave because it can travel through a vacuum.
D. It is a longitudinal wave because the air particles move up and down perpendicular to
the wave direction.
Correct Answer: B
Rationale: This choice is correct because sound waves in air are mechanical
longitudinal waves, meaning the particles of the medium (air) vibrate parallel to the
direction of the wave's energy transport.
Q3: [MANDATORY SCENARIO] You are standing on a train platform waiting for your
ride. Suddenly, you hear a train approaching, and the pitch of its horn sounds high. As
the train passes you and moves away, the pitch of the horn drops noticeably. Which
physical phenomenon best explains this change in pitch?
, A. Diffraction
B. Refraction
C. The Doppler Effect
D. Resonance
Correct Answer: C
Rationale: This matches the physics principle known as the Doppler Effect, which
describes the change in frequency (and pitch) of a wave caused by the relative motion
between the source of the wave and the observer.
Q4: In a physics lab, a student creates a standing wave in a string fixed at both ends.
The student observes points along the string that appear to be perfectly still. What are
these points called?
A. Antinodes
B. Nodes
C. Crests
D. Troughs
Correct Answer: B
Rationale: The best answer is B because nodes are the points in a standing wave
where destructive interference is always maximum, resulting in zero amplitude or no
movement.
Q5: A guitar string is plucked and vibrates at a frequency of 440 Hz. If the length of the
string is halved while keeping the tension constant, what will happen to the fundamental
frequency of the string?
A. It will decrease to 220 Hz.
B. It will remain at 440 Hz.
C. It will increase to 880 Hz.
D. It will become zero because the string is too short.
Correct Answer: C
Rationale: This choice is correct because the frequency of a vibrating string is inversely
proportional to its length; halving the length doubles the frequency (440 Hz × 2 = 880
Hz).
Q6: Which of the following electromagnetic waves has the shortest wavelength?
A. Radio waves
B. Microwaves
C. Visible light
D. Gamma rays
Correct Answer: D
