Waves🐾
Air is blown across the mouth of a long tube, closed at one end. A sound wave is produced in the tube. What is the type of sound wave in the tube?
Longitudinal and stationary
Sound waves travel from water to air. The speed of sound in water is 1500 m/s and in the air is 330 m/s. What are the changes, if any, occurs to its frequency and wavelength?
Frequency remains constant and wavelength decreases.
A sound wave has a frequency of 3000 Hz and a speed of 300m/s. What is the distance between a point of maximum pressure and the adjacent point of minimum pressure?
5 cm
A progressive wave is ___in which wave profile ___ and ___is transferred from one position to another.
one, moves, energy
A stationary wave is___wave in which wave profile ___move and energy ___is not transferred.
one, does not, is not
Amplitude is the___of the___displacement from the___ position.
magnitude, maximum, equilibrium
Wavelength is the __between two adjacent ___or___ which oscillate in ___.
distance, crests, points, phase
Frequency is the number of ___per unit ___.
oscillations, time
A longitudinal wave is __in which the oscillation is___ to the direction of ___of the wave.
one, parallel, propagation
A tuning fork of frequency 512 Hz is set into vibration. The base of the vibrating tuning fork is then placed on top of a horizontal guitar string and is slowly moved along the string. At a certain position of the string, a loud sound is heard. This effect is called ___.
Resonance
A pendulum bob is set into oscillation. Its amplitude gradually decreases. This phenomenon is called ___.
Damping
System A is forced to be vibrated by system B. Resonance is said to occur when system A ___.
vibrates with maximum amplitude
Resonance occurs when___.
a body is made to vibrate at its natural frequency
One end of a string is fixed to a wall and the other end is fixed to a vibrator. The string is under tension. The frequency of the vibrator is gradually increased from zero. At a certain frequency of the vibrator, the string vibrates at a large amplitude. This phenomenon is called ___.
Resonance
Damped oscillation is an oscillation in which there is a ___that ___ its motion. The energy is___ and the amplitude ____ with ___.
force, opposes, lost, decreases, time
Damping effect is desirable.
Shock absorber :
-When a vehicle passes over any ___surfaces, the ___of the wheel will___ and the passagers will be subjected to___ rides.
-____is provided to stop the___in the shortest time.
-uneven, spring, oscillate, uncomfortable
-Critical damping, oscillation
Resonance occurs when the ___of the driving system ___to the ___of the driven system. The driven system then oscillates with maximum ____.
frequency, equals, natural frequency, amplitude
Application of resonance.
Radio receiver :
-The___ of the tuning circuit can be changed by changing the ___.
-If the natural frequency is ___to the frequency of the incoming ___, ___occurs and radio wave is received.
-natural frequency, variable capacitor
-equal, radio waves, resonance
Application of resonance.
Microwave :
-Food have____ water molecules.
-If the ___of microwave transmitted to the food ___to the natural frequency of the ___,___ occurs.
-The water molecules oscillate with ___and the temperature of the food ___.
-oscillating
-frequency, equals, water molecules, resonance
-large amplitude, rises
The oscillation of the pendulum slows down and finally stops. What is the name of this effect? Explain.
-When the pendulum oacillates, the ___opposes its motion.
-Work is done to ___the air resistance.
-The energy is lost as___ to the environment and the amplitude of the oscillation ___.
-air resistance
-resist
-heat loss, decreases
All bridges has similar design and made of similar materials but of different lengths. When earthquake occurs, some bridges may collapse while others do not. Explain.
-The ____of a bridge depends on its ___.
-Bridges with different length have different ___.
-If the natural frequency of the bridge is ___to the frequency of the___wave, ___occurs.
-The bridge vibrate with ___and may collapse.
-natural frequency, length
-natural frequencies
-equal, seismic, resonance
-large amplitude
What happens to the frequency and the strength of a sound wave when reflected?
The frequency remains constant and the strength decreases.
The wave that experiences wave reflection will change in terms of ___.
direction of wave
A progressive wave meets a barrier and bounces back. This is called ___.
Reflection
When a progressive wave is reflected by a barrier, the following remain unchanged except ____.
Direction
A man blows a whistle and he hears the echo from a tall building 2.0 seconds later. If the speed of sound is 340 m/s, what is the distance of the building from the man?
340 m
State the law of reflection.
Angle of incidence = Angle of reflection
An application of reflection of sound in medicine.
-___of higher ___ is used to produce the images of the ____of the human body.
-When ultrasound is ____ to the human body, it is reflected at the ___ between two body tissues.
-The reflected ultrasound is ___ and send to the computer to be ___ and produce an image.
-Ultrasound, frequency, internal structures
-transmitted, boundary
-detected, processed
State the changes, if any, of the speed, frequency and wavelength of the wave after it travels away from the barrier.
The speed, frequency and wavelength remains the same.
Characteristics of radio waves :
-___ waves
-Can propagate without a ___
-Moves ___
-Transverse
-medium
-faster
Characteristics of sound waves :
-____waves
-Needs a ___to propagate
-Moves___
-Longitudinal
-medium
-slower
Explain why the velocity of sound is higher in water than in air.
-Water particles are arranged more ___ than in the air particles.
-Sound waves travel faster in a ___medium.
-closely
-denser
When the plane waves pass through the perspex, the wavelength ___.
Decreases
Water wave travels from deep water region to shallow water region. Its speed slows down. This effect is called ___.
Refraction
What causes the change in the direction of light when it travels from air into water ?
Its speed slows down.
Sound is heard more clearly at night than during the day. This is due to ___.
Refraction
Refraction of waves means when a wave travels from one ___to another, the ___, the ___and the ___ changes, but the frequency remains the same.
medium, velocity, wavelength, direction
State the effect, if any, of refraction on the velocity, wavelength, frequency and direction of the wave.
The velocity, wavelength and the direction of the wave changes but the frequency remains the same.
Explain why the seawater in the bay is calmer compared to that at the cape.
-This is due to ___of waves.
-At the shore, the seabed ___.
-Seawater from the ocean towards the shore is traveling from ___water to ___water.
-The velocity of the water waves ___ and ___takes place.
-The waves are ___away from the normal.
-At the bay, the refraction causes the wave to___.
-The wave energy spreads ___ and the intensity of the waves ___.
-The seawater is ___.
-At the cape, the refraction causes the wave to ___.
-The wave energy ___ into a smaller area and the intensity of the wave ___.
-The waves become ___.
-refraction
-rises
-deeper, shallower
-decreases, refraction
-refracted
-diverge
-out, decreases
-calmer
-converge
-concentrates, increases
-stronger
At night, sound from a faraway source appears clearer and louder compared to the daytime. Explain.
-During the day, air that is closer to the surface of the earth is ___than the air above.
-Sound moves __ in hot air than in cold air.
-As such, sound is ___away from the ground.
-This causes sound cannot be heard ___during the daytime.
-During the night, air that is closer to the surface of the earth is ___.
-Sound is refracted towards ___.
-This causes sound to be heard ___during the night.
-hotter
-faster
-refracted
-clearly
-colder
-the ground
-clearly
Explain why the wavelength in different parts of the water are different.
-When the wave travels from the ___ water region to the ___water region, the wave speed ___.
-The frequency of waves remains the ____.
-Then, the wavelength ___.
-deep, shallow, decreases
-same
-decreases
Relate the depth of water and the wavelength of the wave.
The greater the depth of water, the greater the wavelength of the wave.
State the relationship between the wavelength and the speed of propagation of the wave at a fixed frequency.
The wavelength is directly proportional to the speed of propagation of the wave at a fixed frequency.
Deduce one relationship between the depth of water and the speed of propagation of the wave.
The greater the depth of water, the greater the speed of propagation of the wave.
Water waves in a ripple tank passes through a gap and is diffracted. Which change will cause the diffraction of the wave to decrease?
Decreasing the wavelength of the waves.
What happens to the wavelength after passing through a small gap ?
Remains the same
Diffraction means the___ of a wave when it passes through an ___.
spreading, opening
Water wave spreads out when it passes through a gap between two barriers. Which two factors affect the spreading of the wave?
The width of the gap and the wavelength of the wave.
When light passes through a slit, it spreads out. All the following quantities remain unchanged except ___.
Amplitude
The red laser beam spreads out more compared to the green laser beam. Explain.
-The red light has a ___ wavelength than the green light.
-Hence, the ___ effect of the red light is ___than the green light.
-The red laser spreads out ___ compared to the green laser.
-longer
-diffraction, larger
-more
A wave is a ____ generated by an oscillating source.
disturbance
Relate the size of the gap to the spreading area of the light wave.
The smaller the size of the gap, the greater the spread of light.
Relate the size of the gap to the brightness of the bright spot formed on the screen.
The larger the size of the gap, the brighter the bright spot formed on the screen.
Wheb the light from two separate lamps falls on a screen, no interference fringe pattern is seen. This is because ___.
the lights from the lamp are not coherent
Interference of wave is the ____ of two or more waves from a ___ source of waves.
superposition, coherent
What is the experimental evidence that light is a wave ?
Light can show the properties of diffraction and interference.
Coherent sources means the __ difference between sources remains ___ and the frequency of the two sources is the ___.
phase, constant, same
Application of interference on a camera lens.
-To reduce the ___ of light from the lens, the lens is coated with a thin layer of a material.
-The thickness of the coated material is such that the reflected ___ light undergoes ____ interference.
-Effectively, green colour light is not ___.
-Only other colour lights are ___ reflected.
-Hence, the camera lens appears ___ in colour.
-reflection
-green, destructive
-reflected
-partially
-purplish
Monochromatic light is the light that has ___ value of ___.
one, wavelength
Explain the condition at the positions where loud sound is heard.
-Both sound waves meet in ___.
-_____ interference occurs.
-The amplitude ___ and the intensity of sound is ___.
-phase
-Constructive
-increases, maximum
Going from ultraviolet to microwave, the frequency ____ and the speed of electromagnetic waves is the ___.
decreases, same
An electromagnetic wave has a wavelength of 1 x 10^-9 m. What type of wave is this?
X-rays
The types of electromagnetic wave having the longest wavelength is
Radio waves
Mechanical waves are waves that ____ medium to propagate, whereas electromagnetic waves are waves that can travel through ____.
requires, vacuum