Gelombang dan Bunyi Practice Questions
UN (Indonesia) · UN Fisika · 134 free MCQs with instant results and detailed explanations.
134
Total
36
Easy
72
Medium
26
Hard
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Sample Questions from Gelombang dan Bunyi
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Q1
Easy
If the frequency of a sound wave is 440 Hz, what is its wavelength in air at 20ยฐC?
A.
0.78 m
B.
0.34 m
C.
1.12 m
D.
1.00 m
Show Answer & Explanation
Correct Answer: A
Using the formula wavelength = speed/frequency, we find the wavelength by dividing the speed of sound (343 m/s) by the frequency (440 Hz), which gives approximately 0.78 m.
Q2
Easy
What is the primary characteristic that distinguishes sound waves from light waves?
A.
Sound waves are longitudinal, while light waves are transverse.
B.
Sound waves travel faster than light waves.
C.
Sound waves can travel through a vacuum, light waves cannot.
D.
Sound waves require less energy to travel than light waves.
Show Answer & Explanation
Correct Answer: A
Sound waves are classified as longitudinal waves because the particles of the medium move parallel to the direction of wave propagation. In contrast, light waves are transverse waves where the oscillations are perpendicular to the direction of travel.
Q3
Easy
If the frequency of a sound wave is doubled, what happens to its wavelength?
A.
It doubles.
B.
It remains the same.
C.
It halves.
D.
It increases by a factor of three.
Show Answer & Explanation
Correct Answer: C
According to the wave equation, the speed of sound is equal to the product of frequency and wavelength. If the frequency is doubled, the wavelength must halve to maintain the same speed of sound in a given medium.
Q4
Medium
What happens to the pitch of a sound when its frequency increases?
A.
It decreases
B.
It remains constant
C.
It increases
D.
It becomes inaudible
Show Answer & Explanation
Correct Answer: C
The pitch of sound is directly related to its frequency; as frequency increases, so does the perceived pitch. Therefore, when the frequency of a sound increases, the pitch also increases.
Q5
Medium
In a longitudinal wave, the regions where particles are close together are called?
A.
Crests
B.
Troughs
C.
Compressions
D.
Rarefactions
Show Answer & Explanation
Correct Answer: C
In longitudinal waves, the regions where particles are close together are referred to as compressions, while the regions where particles are spread apart are called rarefactions. Hence, the correct answer is compressions.
Q6
Medium
What is the frequency of a sound wave if its wavelength is 0.85 meters and the speed of sound in air is approximately 343 meters per second?
A.
403.53 Hz
B.
300 Hz
C.
287.65 Hz
D.
200 Hz
Show Answer & Explanation
Correct Answer: A
The frequency can be calculated using the formula: frequency = speed / wavelength. Here, frequency = 343 m/s / 0.85 m = 403.53 Hz.
Q7
Medium
Which of the following statements best describes amplitude in a sound wave?
A.
The distance between two consecutive crests.
B.
The maximum displacement of particles from their equilibrium position.
C.
The speed at which sound travels in a medium.
D.
The frequency of the sound wave.
Show Answer & Explanation
Correct Answer: B
Amplitude refers to the maximum displacement of particles from their rest position in a wave. It indicates the energy of the sound wave.
Q8
Hard
A sound wave travels through air at a speed of 340 m/s. If the frequency of the sound wave is 170 Hz, what is the wavelength of the sound wave?
A.
2 m
B.
1.5 m
C.
0.5 m
D.
3 m
Show Answer & Explanation
Correct Answer: A
The wavelength (ฮป) can be calculated using the formula ฮป = v/f, where v is the speed of sound and f is the frequency. Here, ฮป = 340 m/s / 170 Hz = 2 m, making option A correct.
Q9
Hard
If the intensity level of a sound is measured at 90 dB, what is the corresponding intensity in watts per square meter (W/mยฒ)?
A.
0.001 W/mยฒ
B.
0.01 W/mยฒ
C.
0.1 W/mยฒ
D.
1 W/mยฒ
Show Answer & Explanation
Correct Answer: C
The intensity level in decibels (dB) is calculated using the formula L = 10 log10(I/I0), where I0 is the reference intensity (10^-12 W/mยฒ). To find intensity I for 90 dB: 90 = 10 log10(I/10^-12) implies I = 10^-12 * 10^9 = 0.1 W/mยฒ, confirming option C.
Q10
Hard
A tuning fork vibrates at a frequency of 512 Hz, producing a sound wave in air. If the sound intensity at a distance of 2 meters from the fork is measured to be 0.04 W/mยฒ, what will be the sound intensity at a distance of 6 meters from the fork, assuming isotropic radiation?
A.
0.01 W/mยฒ
B.
0.02 W/mยฒ
C.
0.04 W/mยฒ
D.
0.06 W/mยฒ
Show Answer & Explanation
Correct Answer: A
Intensity of sound varies inversely with the square of the distance. Using the formula I2 = I1 * (r1^2 / r2^2), where I1 is 0.04 W/mยฒ, r1 is 2m, and r2 is 6m, we can find I2 = 0.04 * (2^2 / 6^2) = 0.01 W/mยฒ.
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Gelombang dan Bunyi โ UN (Indonesia) UN Fisika Practice Questions Online
This page contains 134 practice MCQs for the chapter Gelombang dan Bunyi in UN (Indonesia) UN Fisika. The questions are organized by difficulty โ 36 easy, 72 medium, 26 hard โ so you can choose the right level for your preparation.
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