What is the definition of intensity in the context of waves?
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The amount of energy passing through a unit area per unit time.
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What is the definition of intensity in the context of waves?
The amount of energy passing through a unit area per unit time.
What type of wave is a transverse wave?
A wave in which the particles of the medium move perpendicular to the direction of the wave.
What is the relationship between pressure and the speed of sound in a medium?
The speed of sound in a medium is directly proportional to the square root of the pressure in the medium.
How is intensity defined?
Energy carried by wave passing normally through unit area, S in unit time.
What does the notation 'N19/P11/Q21 EES 90in up going down' indicate for a transverse wave?
It indicates the position, phase, and direction of the wave.
How can the frequency of sound be determined using a calibrated cathode-ray oscilloscope (C.R.O.)?
By capturing sound waves with a microphone, converting them into electrical signals, and displaying the wave pattern on the C.R.O. screen to count the number of divisions occupied by one cycle of the wave.
What is the symbol for the proportionality constant between pressure and the speed of sound?
α (alpha).
What happens when a wave is held at both end points?
The wave does not propagate, only vibrating up and down, trapping energy.
What is the relationship between intensity and amplitude?
Intensity is proportional to the square of the amplitude.
How is the wavelength of sound determined using stationary waves?
By using superposition to measure the separation of pulses on the C.R.O. when sound waves are used instead of radio waves, considering the speed of sound as 300 m/s.
What is the term for a surface containing points affected in the same way by a wave at a given time?
Wavefront.
What are transverse waves?
Waves in which the particles of the medium move perpendicular to the direction of the wave.
What are the properties that all waves can exhibit?
Reflection, refraction, diffraction, and interference patterns.
What is Brewster's angle?
Brewster’s angle is an angle of incidence at which light with a particular polarization is perfectly transmitted through a surface.
What are longitudinal waves?
Waves in which the particles of the medium move parallel to the direction of the wave.
What are the characteristics of all electromagnetic waves?
They are transverse waves, travel with the same speed in free space, and can be polarised.
Which type of waves can be polarized?
Only transverse waves.
What happens when unpolarized light passes through the first polarizer?
Half the intensity of the wave is always lost.
What is diffraction?
The spreading out of waves when passing through a narrow gap.
Why can longitudinal waves, like sound waves, not be polarised?
Because they oscillate parallel to the direction of travel.
What is polarisation?
Polarisation is a phenomenon associated with transverse waves where vibrations are restricted to a particular direction perpendicular to the direction of propagation/energy transfer.
What is meant by equilibrium in a wave?
The position where the particles of the medium are at rest.
What is the approximate range of wavelengths in free space for the principal regions of the electromagnetic spectrum?
From radio waves to gamma rays.
How is refraction of waves demonstrated using a glass block?
Submerging a glass block in water produces a sudden change in the depth of the water, causing the waves to change speed and direction.
What is the relationship between the refractive indices n1 and n2 in Brewster's angle?
n1 is the refractive index of the initial material (e.g., air) and n2 is the refractive index of the material scattering the light.
What does the extent of diffraction depend on?
The width of the gap compared with the wavelength.
What is Malus's law used for?
Malus's law (I = I0 cos^2θ) is used to calculate the intensity of a plane polarised electromagnetic wave after transmission through a polarising filter or a series of polarising filters.
How can waves be polarised?
Through a polariser or polarising filter, which only allows oscillations in a certain plane to be transmitted.
What is rarefaction in a longitudinal wave?
The region where the particles are spread apart.
What range of wavelengths in free space is visible to the human eye?
400 – 700nm.
What is a wave?
A wave is any disturbance that moves from equilibrium position.
If the polarizing axis of the second polarizer is 30° to that of the first, what is the intensity emerging from the second polarizer?
0.75 I
How is interference defined?
As the resultant displacement when two or more waves overlap.
What is the difference between progressive waves and standing waves?
Progressive waves transfer energy from one point to another, while standing waves do not transfer energy and are formed by the interference of two waves.
What is an application of polarization in everyday life related to reducing glare?
Reduces glare from reflecting surfaces, such as in sunglasses.
How are transverse waves polarised?
Transverse waves can be polarised by restricting vibrations to a specific direction perpendicular to the direction of propagation/energy transfer.
What is the speed of electromagnetic waves in vacuum?
3.0 × 10^8 m/s.
What provides a way for the transfer of energy from one point to another without the physical transfer of any material medium between the points?
Wave motion.
What is Malus's Law?
Malus's law states that if the analyser is rotated by an angle θ with respect to the polariser, the intensity of the light transmitted by the analyser is given by I = I0 * cos²(θ).
What is the Doppler effect?
The increase or decrease in the frequency of sound, light, or other waves as the source and observer move towards or away from each other.
What is polarisation?
The property of waves restricted to vibrations in a certain plane.
How do transverse and longitudinal waves differ?
Transverse waves have oscillations perpendicular to the direction of wave propagation, while longitudinal waves have oscillations parallel to the direction of wave propagation.
What is the difference between unpolarised and polarised waves?
Unpolarised waves vibrate in random directions but always in a plane at right angles to the direction of energy transfer, while polarised waves have full restriction to the direction of vibration on a single plane.
How is stress analysis used in everyday life with the help of polarization?
Engineers make models out of transparent materials and observe the fringe pattern formed to identify regions of high stress.
What are the properties of electromagnetic waves?
They can be polarised, travel with the same speed in vacuum, can be refracted and diffracted, do not need a medium, and can transfer energy from one place to another.
How many types of waves are there?
Three types of waves.
How does the intensity of unpolarised light change when it passes through a polariser?
The intensity of the transmitted polarised light falls by half.
What is the wavelength of the wave on the rope?
1.5 m.
How is the observed frequency affected when the source is moving away or approaching the observer?
The observed frequency is affected by the speed of the source and the speed of sound in the medium.
What is the difference between transverse and longitudinal waves?
Transverse waves vibrate perpendicular to the direction of wave travel, while longitudinal waves vibrate parallel to the direction of wave travel.
What do the terms wavelength, period, and amplitude represent on a wave graph?
Wavelength is the distance between two consecutive crests or troughs, period is the time taken for one complete wave cycle, and amplitude is the maximum displacement of a wave from its equilibrium position.
How can poor TV reception in hilly areas be corrected using polarization?
The main transmitter emits waves that are vertically polarized, and the relay station emits waves that are horizontally polarized.
What happens if the analyser is rotated by 90° with respect to the polariser?
The intensity of the light transmitted by the analyser will be zero, since cos(90°) = 0.
What are the two categories into which waves can be classified?
Progressive & Standing waves.
Explain the term 'displacement' for the wave on the rope.
Open-ended question, no specific answer provided.
How can transverse and longitudinal waves be compared?
By analyzing and interpreting graphical representations of both types of waves.
What is the formula for the observed wavelength when the source is moving away from the observer?
The observed wavelength = (velocity of sound + velocity of the source) / frequency of the source.
What is the wave equation?
The wave equation describes the propagation of waves and is used to analyze the behavior of waves in various mediums.
What type of light will a polariser transmit?
A polariser will only transmit light that is polarised parallel to its transmission axis.
What are the two kinds of progressive waves?
Transverse & Longitudinal waves.
Calculate the amplitude for the wave on the rope.
Answer not provided.
What is the formula for the observed wavelength when the source is moving towards the observer?
The observed wavelength = (velocity of sound - velocity of the source) / frequency of the source.
Give an example of transverse waves.
When a stretched rope is flipped at one end.
Calculate the speed of the wave on the rope.
Answer not provided.
What is the effect of the motion of a distant star moving away from a stationary observer?
The light observed from the star is red-shifted.
Give an example of longitudinal waves.
When one end of a coil spring is compressed.
Draw the wave pattern on the rope at a time 0.050 s later than that shown in Fig. 5.1.
Open-ended question, no specific answer provided.
What are Longitudinal Waves?
Waves consisting of series of compression (regions of high pressure) and rarefaction (regions of low pressure). Examples include water waves and light waves.
How can the speed of a car be calculated using the observed frequency of its horn and the speed of sound in air?
By using the formula: speed of the car = speed of sound * ((observed frequency - source frequency) / source frequency).
What is displacement (x)?
Distance moved in a specified direction from rest position.
What are the three types of waves?
Mechanical Waves, Electromagnetic Waves, Matter Waves.
State and explain whether the waves on the rope are progressive or stationary.
Answer not provided.
How are transverse and longitudinal waves graphically represented?
Both transverse and longitudinal waves could be graphically represented by displacement-distance and displacement-time graphs.
What is the Doppler effect?
The change in observed frequency when a source of waves moves relative to a stationary observer.
What is amplitude (x₀)?
The displacement of a wave from its rest position.
State and explain whether the waves on the rope are longitudinal or transverse.
Answer not provided.
What is a displacement-distance graph used to represent?
The graph shows the displacement of the vibrating particles or the transmitting medium at different distances from the source at a certain instant.
What is the expression for the observed frequency when a source of sound waves moves relative to a stationary observer?
f' = (v +/- vo) / (v - vs) * fo
Define wavelength for a wave.
Wavelength (𝜆) is the distance between two consecutive points in a wave that are in phase.
Define wavelength (𝜆).
The distance between 2 adjacent peaks, crests, or troughs.
What is the phase difference between points X and Y on the surface of water in a ripple tank?
Answer choices: A) 45° B) 135° C) 180° D) 270°.
What does a displacement-time graph show?
The graph shows the displacement of one particle at a particular distance from the source varies with time.
What is an example of the Doppler Effect with sound waves?
The change in pitch of a note heard when an emergency vehicle passes by while sounding its siren.
Define frequency for a wave.
Frequency (f) is the number of complete oscillations or cycles of a wave that occur in a unit of time.
What is period (T)?
The time taken to complete 1 oscillation or 1 cycle.
How are the vibrations of particles in a longitudinal wave oriented?
The vibrations of the particles in the wave are parallel in the same direction to the direction in which the wave is traveling.
What happens to the pitch of the note as an emergency vehicle approaches and recedes from a stationary observer?
The pitch is higher as it approaches and lower as it recedes.
Deduce the relationship between wavelength (𝜆), frequency (f), and the speed (v) of the wave.
The relationship is given by the equation v = 𝜆 * f, where v is the speed of the wave, 𝜆 is the wavelength, and f is the frequency.
What is frequency (f)?
The number of complete waves produced per unit time, measured in hertz (Hz).
What is the observed frequency when the source is stationary and the observer is stationary?
No change in observed frequency.
Can electromagnetic waves travel through a vacuum?
Yes, electromagnetic waves can travel through a vacuum.
For plane waves on the surface of water with a frequency of 2.5 Hz, determine the amplitude.
Amplitude = ......................................... mm
What is speed (𝑣) in terms of frequency (f) and wavelength (𝜆)?
𝑣 = 𝑓𝜆
Can sound waves travel through a vacuum?
No, sound waves cannot travel through a vacuum.
How does the observed frequency change when the source is moving towards one observer and away from another?
The observer towards which the source is moving observes a higher frequency, and the observer from which the source is receding observes a lower frequency.
For plane waves on the surface of water with a frequency of 2.5 Hz, determine the speed.
Speed = ....................................... m s – 1
What is a wavefront?
A line showing the position of the crest of a wave.
Can longitudinal waves be polarised?
No, longitudinal waves cannot be polarised.
For plane waves on the surface of water with a frequency of 2.5 Hz, determine the phase difference between points A and B.
Phase difference = ................................ unit .........
Define phase.
A line or surface on which the disturbance is in phase at all points, or the timing of a point within a wave cycle.
Describe briefly, with the aid of a sketch diagram, how the wave may be observed in a ripple tank.
Use a strobe or video camera to view the clear wavefront produced.
What is phase difference?
The point or wave is ahead or behind another point in degrees or radians.
A health inspector measures the intensity of a sound. Near a loudspeaker, his meter records an intensity I. At another position, the meter gives an intensity reading of 2I. What is the corresponding amplitude of the sound wave?
The corresponding amplitude is 2A.
Wave 1 has an intensity of 1.6 × 10 – 6 W m – 2. What is the intensity of wave 2?
The intensity of wave 2 is 2.4 × 10 – 6 W m – 2.
