intro
Question 1:
Which of the following does not qualify as a mechanical wave?
Topic: Classification of Waves
Correct Answer: B) Ultra violet
- Mechanical waves require a medium for propagation.
- Ultra-sonic waves, infra-sonic waves, and audible waves are all variations of sound waves, which are mechanical by nature.
- On the other hand, ultra-violet waves are a type of electromagnetic wave, which can travel even in vacuum.
- Therefore, the correct answer is B, "Ultra violet".
Question 2:
At what particular temperature does the speed of sound in air become twice its speed at 20°C?
Topic: Sound Velocity and Temperature
Correct Answer: C) 899°C
- The speed of sound in air is directly proportional to the square root of the absolute temperature.
- Therefore, to double the speed, the temperature must quadruple from the reference temperature of 20°C (293K).
- Hence, the correct response is C, "899°C".
Question 3:
In a stationary wave, how far is it between successive nodes?
Topic: Wave Interference and Node Distance
Correct Answer: A) λ/2
- In a standing or stationary wave, the distance between two consecutive nodes (points of minimum amplitude) is half the wavelength of the wave, denoted as λ/2.
- Therefore, the correct response is A, "λ/2".
Question 4:
What is the distance between a node and the nearest anti-node in a stationary wave?
Topic: Node and Antinode in Stationary Waves
Correct Answer: D) λ/4
- A stationary wave is characterized by nodes and anti-nodes.
- The distance between an anti-node (point of maximum amplitude) and the closest node is one-fourth of the wavelength, often denoted as λ/4.
- Therefore, the correct answer is D, "λ/4".
Question 5:
What is the primary reason that sound travels faster through solids compared to gases?
Topic: Sound Propagation in Different Media
Correct Answer: B) Elasticity
- The velocity of sound is influenced by the elasticity of the medium through which it travels. Solids, being more elastic than gases, facilitate a higher speed of sound.
- Thus, the correct answer is B, "Elasticity".
Question 6:
What is observed when stars move away from Earth?
Topic: Redshift and Blueshift in Astronomy
Correct Answer: A) Red shift
- A redshift is observed when the wavelength of light from an object moving away from the observer is stretched, causing it to shift towards the longer-wavelength (redder) end of the spectrum.
- Therefore, the correct answer is A, "Red shift".
Question 7:
In which direction do particles in a medium vibrate during the propagation of transverse waves?
Topic: Characteristics of Transverse Waves
Correct Answer: B) At a right angle to the wave's direction
- Transverse waves are distinguished by the motion of particles in the medium, which oscillate perpendicular to the direction of the wave's propagation.
- Thus, the correct answer is B, "In a right angle to the wave's direction".
Question 8:
What are the waves called where the medium's particles move in the same direction as the wave?
Topic: Types of Waves Based on Particle Movement
Correct Answer: B) Longitudinal waves
- Longitudinal waves are characterized by the parallel movement of particles in the medium to the direction of the wave. Thus, when the wave advances, the particles in the medium oscillate back and forth along the direction of the motion of the wave.
- Consequently, the right answer is B, "Longitudinal waves".
Question 9:
In the case of longitudinal waves, how do the particles of the medium behave?
Topic: Particle Behaviour in Longitudinal Waves
Correct Answer: A) They vibrate in the direction of the wave motion
- In longitudinal waves, the medium's particles move back and forth along the line of wave motion, which is parallel to the direction of wave propagation.
- Hence, the correct answer is A, "They vibrate in the direction of the wave motion".
Question 10:
Which attribute differentiates between longitudinal and transverse waves?
Topic: Distinctive Features of Longitudinal and Transverse Waves
Correct Answer: D) Polarization
- Polarization, which is the orientation of the oscillations in a transverse wave, is a property exclusive to transverse waves and not applicable to longitudinal waves.
- Therefore, the correct answer is D, "Polarization".
Question 11:
What is the distance from a node to an anti-node in standing waves?
Topic: Node-Antinode Distance in Standing Waves
Correct Answer: B) A quarter of the wavelength (λ/4)
- In standing waves, the distance between the node (point of minimum amplitude) and the anti-node (point of maximum amplitude) can be calculated.
- The distance between two successive nodes is half the distance between two successive anti-nodes, which is a quarter of the wavelength (λ/4).
- So, the correct answer is B, "A quarter of the wavelength (λ/4)".
Question 12:
While a sound wave travels via an air column in the form of compressions and rarefactions, what accurately describes the relationship between consecutive compressions and rarefactions?
Topic: Behavior of Sound Waves in Compressions and Rarefactions
Correct Answer: D) No heat exchange occurs.
- Sound waves propagate as compressions and rarefactions in an air column.
- During this propagation, according to Laplace, the process is adiabatic, implying there is no exchange of heat between compressions and rarefactions.
- Therefore, the correct answer is D, "No heat exchange occurs".
Question 13:
At 0 degrees Celsius, what's the speed of sound in a vacuum?
Topic: Velocity of Sound in Vacuum
Correct Answer: D) None of these
- Sound waves need a medium to propagate, meaning they cannot travel in a vacuum.
- Hence, irrespective of the temperature, the velocity of sound in a vacuum is zero.
- So, the correct response is D, "None of these".
Question 14:
At 0 degrees Celsius, the speed of sound is 332ms-1. At what temperature would this speed double to 664ms-1?
Topic: Speed of Sound at Different Temperatures
Correct Answer: C) 819°C
- The speed of sound in air increases by about 0.6m/s for every degree Celsius increase in temperature.
- Therefore, to double the speed from 332m/s to 664m/s, the temperature must increase by approximately 546 degrees Celsius.
- Thus, starting from 0 degrees Celsius, the temperature at which the speed of sound is 664m/s is 546 degrees Celsius.
- So the correct answer is C, "819°C".
Question 15:
What method do bats use to navigate and locate their prey?
Topic: Animal Navigation Techniques
Correct Answer: C) Echolocation
- Bats utilize echolocation, a technique where sound waves and echoes are used to determine the location of objects in space.
- This method allows bats to navigate and locate their food in complete darkness.
- Echolocation involves bats emitting sound waves from their mouth or nose, which bounce off objects and return to the bat, informing them of the object's location and size.
- Therefore, the correct answer is C, "Echolocation".
Question 16:
If a wave travels at a speed of 20ms-1 and 20 waves pass through the medium in 1 second, what is the wavelength of the wave?
Topic: Wavelength Calculation
Correct Answer: D) 1m
- The relationship between wave speed (V), frequency (f), and wavelength (λ) is given by the equation V = fλ.
- Given that the speed is 20ms-1 and 20 waves (which is the frequency) pass through the medium in a second, we can substitute these values into the equation to find the wavelength.
- Solving for λ gives us λ = V/f = 20ms-1 / 20Hz = 1m.
- Thus, the correct answer is D, "1m".
Question 17:
Within a vibrating cord or string, which term refers to the points of maximum amplitude?
Topic: Vibrations and Waves
Correct Answer: A) Antinodes
- In the context of a standing wave such as a vibrating cord or string, the locations of maximum displacement (amplitude) are known as antinodes.
- The direct opposite of antinodes are nodes, which are points of minimum displacement. Vibrating guitar strings, for example, have nodes at their ends.
- Therefore, the correct response is A, "Antinodes".
Question 18:
A stationary sound wave has a frequency of 165Hz, and the speed of sound in air is 330m/s. What is the distance between two successive nodes?
Topic: Sound Waves and Nodes
Correct Answer: B) 1m
- The wavelength (λ) can be computed using the equation λ = V/f, where V is the velocity of sound and f is frequency.
- Substituting the given values, we get λ = 330m/s / 165Hz = 2m.
- However, the distance between two successive nodes is half the wavelength, or λ/2.
- Thus, the correct answer is B, "1m".
Question 19:
A motorist driving at 30 m/s towards a hill honks a 600Hz horn. Considering the speed of sound in air is 330 m/s, what would be the frequency of the reflected sound audible to the motorist?
Topic: Sound Frequency and Reflection
Correct Answer: C) 720 Hz
- The frequency of the reflected sound in this scenario can be determined using the Doppler effect, which describes how the frequency of a wave changes relative to an observer moving relative to the source of the wave.
- By applying the appropriate formula taking into account the speed of the car, the speed of sound and the frequency of the horn, we can calculate the frequency of the reflected sound.
- Therefore, the correct answer is C, "720 Hz".
Question 20:
Which type of waves are characterized by the perpendicular vibration of medium's particles to the direction of wave propagation?
Topic: Wave Types and Properties
Correct Answer: D) Transverse waves
- Transverse waves are defined as waves in which the particles of the medium move in a direction perpendicular to the wave's motion.
- On the contrary, in longitudinal waves, particles oscillate back and forth along the wave's direction.
- Examples of transverse waves include water waves and seismic waves, whereas sound waves are an example of longitudinal waves.
- Therefore, the correct answer is D, "Transverse waves".
Question 21:
The standard speed of sound in the air is 332 m/s. What is the speed of sound in the air at 0°C and 4 atm pressure?
Topic: Physical Properties of Sound Waves
Correct Answer: B) 332 m/s
- Contrary to popular belief, the speed of sound does not rely on the pressure of the medium.
- Therefore, even if the atmospheric pressure is quadrupled, the speed of sound remains constant at the same temperature.
- So, the sound speed at 0°C and 4 atm should be the same as at STP, i.e., 332 m/s.
- Therefore, the correct answer is B, "332 m/s".
Question 22:
By what percentage was Newton's calculated value for the speed of sound at STP incorrect?
Topic: History of Sound Speed Calculations
Correct Answer: D) 16%
- Sir Isaac Newton, a renowned physicist, made a significant miscalculation in his original computation of sound speed.
- This error is well-documented in physics textbooks.
- The discrepancy between his value and the actual value is approximately 16%.
- Therefore, the correct answer is D, "16%".
Question 23:
If a sound source generates a 400Hz frequency but the receiver perceives it as 390Hz, what can be inferred?
Topic: Doppler Effect
Correct Answer: C) The listener is receding from the source
- The Doppler effect explains why the perceived frequency of a sound differs from its source frequency, especially when there's relative motion between the observer and the source.
- In this case, the received frequency is less than the emitted frequency, suggesting the listener is moving away from the source.
- Hence, the correct answer is C, "The listener is receding from the source".
Question 24:
In a standing wave, what is the particle velocity at the node?
Topic: Wave Mechanics
Correct Answer: C) Zero
- A standing wave is characterized by nodes and antinodes.
- At a node, the particles of the medium are at rest, implying that their velocity is zero.
- Therefore, the correct answer is C, "Zero".
Question 25:
When a wave transitions from one medium to another, what characteristic remains unchanged?
Topic: Wave Propagation
Correct Answer: B) Frequency
- A wave's frequency is determined solely by its source and remains constant when the wave moves from one medium to another.
- Other properties, such as speed and wavelength, can alter depending on the medium's properties.
- So, the correct answer is B, "Frequency".
Question 26:
If the frequency of a woman's voice is 600Hz and a man's voice is 200Hz, what would be the ratio of their wavelengths?
Topic: Sound Wave Properties
Correct Answer: B) 1:3
- The frequency of a wave and its wavelength are inversely proportional. In simple terms, as one increases, the other decreases.
- Given that the woman's frequency is thrice that of the man's, the man's wavelength should be thrice that of the woman's.
- Therefore, the correct answer is B, "1:3".
Question 27:
By how much does the speed of sound in air increase for every 1°C rise in temperature?
Topic: Sound Speed and Temperature
Correct Answer: C) 0.61 m/s
- The velocity of sound in air indeed changes with varying temperatures.
- For each degree-Celsius increase in temperature, the speed of sound typically accelerates by 0.61 m/s.
- Therefore, the correct answer is C, "0.61 m/s".
Question 28:
What is the wavelength of the fundamental mode of vibration for a pipe that is closed at one end?
Topic: Acoustics
Correct Answer: C) 4l
- A pipe that is closed at one end and open at the other creates a fundamental or first harmonic wave, where closed end acts as node and open end as antinode.
- The distance between a node and an antinode is λ/4, which equals the length of the pipe.
- Therefore, the wavelength (λ) is four times the length of the pipe (4l).
- Thus, the correct answer is C, "4l".
Question 29:
Which of these phenomena is exemplified by the reflection of radar waves off an airplane?
Topic: Wave Reflection and Doppler Effect
Correct Answer: B) Doppler Effect
- Radar employs radio waves to determine the velocity and altitude of an airplane.
- The Doppler Effect describes how the wavelength of reflected waves changes depending on whether the airplane is approaching or withdrawing from the radar.
- Therefore, the correct answer is B, "Doppler Effect".
Question 30:
What is the distance between two consecutive troughs or crests in a wave?
Topic: Wave Characteristics
Correct Answer: C) λ
- In a wave, the distance between two consecutive crests or troughs is equal and called the wavelength.
- Therefore, the correct answer is C, "λ".
Question 31:
What is a stationary wave comprised of?
Topic: Stationary Waves
Correct Answer: C) Nodes and antinodes
- A stationary wave, also known as a standing wave, is one in which certain points, known as nodes, have zero displacement.
- The points of maximum displacement are called antinodes.
- Therefore, the correct answer is C, "Nodes and antinodes".
Question 32:
Where are the nodes located in stationary waves set up in a medium?
Topic: Stationary Waves and Node Locations
Correct Answer: C) nλ/2
- In stationary waves, the distance between two consecutive nodes is represented by the equation nλ/2, where n stands for the numbers 1, 2, 3, etc.
- Therefore, the correct answer is C, "nλ/2".
Test Results
Number of Correct Answers: 0
Number of Skipped Questions: 0
Number of Incorrect Answers: 0
Total Marks: 0