Red light is used for signals because it has – (1) long wavelength (2) high intensity (3) high frequency (4) low refraction in the medium

Red light is used for signals because it has – (1) long wavelength (2) high intensity (3) high frequency (4) low refraction in the medium
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(1) long wavelength Explanation: Red is the international colour of stop signs and stop lights on highways and intersections because it is scattered the least by air molecules. The effect of scattering is inversely related to the fourth power of the wavelength of a colour. Red has the highest wavelength of all the colours and is able to travel the longest distance through fog, rain, and the alike.
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Red light is used for signals because it has (1) long wavelength (2) high intensity (3) high frequency (4) low refraction in the medium

Description : Red light is used for signals because it has (1) long wavelength (2) high intensity (3) high frequency (4) low refraction in the medium

Last Answer : long wavelength

The speed of light in vacuum "C" divided by the Index of Refraction "N" gives the: w) frequency of the light x) speed of the light in the medium y) energy of the light z) wavelength of the light

Description : The speed of light in vacuum "C" divided by the Index of Refraction "N" gives the: w) frequency of the light x) speed of the light in the medium y) energy of the light z) wavelength of the light

Last Answer : ANSWER: X -- SPEED OF THE LIGHT IN THE MEDIUM

The danger signals are red while the eye is more sensitive to yellow because – (1) absorption in red is less than yellow and hence red is visible from a distance (2) scattering in yellow light is less than red (3) the wavelength of red light is more than yellow light (4) none of the above reasons

Description : The danger signals are red while the eye is more sensitive to yellow because – (1) absorption in red is less than yellow and hence red is visible from a distance (2) scattering in yellow light is less than red (3) the wavelength of red light is more than yellow light (4) none of the above reasons

Last Answer : (3) the wavelength of red light is more than yellow light

Hertz is a unit for measuring – (1) Intensity of waves (2) Frequency of waves (3) Wavelength (4) Clarity of waves

Description : Hertz is a unit for measuring – (1) Intensity of waves (2) Frequency of waves (3) Wavelength (4) Clarity of waves

Last Answer : (2) Frequency of waves

Which of the following property of sound is affected by change in air temperature – (1) Frequency (2) Intensity (3) Amplitude (4) Wavelength

Description : Which of the following property of sound is affected by change in air temperature – (1) Frequency (2) Intensity (3) Amplitude (4) Wavelength

Last Answer : (4) Wavelength Explanation: The wavelength of sound changes with temperature. This is because the speed of sound changes with the temperature. Since the speed of sound is different at different temperature, this ... while the same tone in fresh water at 68°F would have a wavelength of 48.05 feet.

Which of the following property of sound is affected by change in air temperature (1) Frequency (2) Intensity (3) Amplitude (4) Wavelength

Description : Which of the following property of sound is affected by change in air temperature (1) Frequency (2) Intensity (3) Amplitude (4) Wavelength

Last Answer : Wavelength

Hertz is a unit for measuring (1) Intensity of waves (2) Frequency of waves (3) Wavelength (4) Clarity of waves

Description : Hertz is a unit for measuring (1) Intensity of waves (2) Frequency of waves (3) Wavelength (4) Clarity of waves

Last Answer : Frequency of waves

A beam of light is incident on a large block of glass. The index of refraction of the glass is greater than one. Is the wavelength of the light in the glass: w) longer than x) shorter than y) the same as the wavelength of the light in the air?

Description : A beam of light is incident on a large block of glass. The index of refraction of the glass is greater than one. Is the wavelength of the light in the glass: w) longer than x) shorter than y) the same as the wavelength of the light in the air?

Last Answer : ANSWER: X -- SHORTER THAN 

Light is normally incident on a thin soap film and is reflected. If the wavelength of this light is "L" and the index of refraction of the soap film is "N", complete destructive interference will occur for a film thickness of: w) L / 8N x) L / 4N y) L / 2N z) 3L / 4N

Description : Light is normally incident on a thin soap film and is reflected. If the wavelength of this light is "L" and the index of refraction of the soap film is "N", complete destructive interference will occur for a film thickness of: w) L / 8N x) L / 4N y) L / 2N z) 3L / 4N

Last Answer : ANSWER: Y -- L / 2N 

Coherent light of a single frequency passes through a double slit with a separation d, to produce a pattern on a screen as distance D from the slits. What would cause the separation between adjacent minima on the screen to increase? A. A. increase the index of refraction of the medium in which the setup is immersed B. increase the separation d between the slits C. increase the distance D. increase the frequency of the incident light

Description : Coherent light of a single frequency passes through a double slit with a separation d, to produce a pattern on a screen as distance D from the slits. What would cause the separation between adjacent ... d between the slits C. increase the distance D. increase the frequency of the incident light

Last Answer : B. increase the separation d between the slits

The refractive indices of four media A, B, C and D are given in the following table: light-reflection-and-refraction-chapter-wise-important-questions-class-10-science-9 If light, travels from one medium to another, in which case the change in speed will be (i) minimum, (ii) maximum? -Physics

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Last Answer : (i) Minimum change is seen as light moves between 1.50 and 1.52, i.e. B and C. (ii) Maximum change when light moves between 1.33 and 2.40, i.e. A and D.

A light ray travelling from denser to rarer medium at an angle of incidence more than critical angle of concerned media pair suffers. (1) reflection (2) refraction (3) diffraction (4) total internal reflection

Description : A light ray travelling from denser to rarer medium at an angle of incidence more than critical angle of concerned media pair suffers. (1) reflection (2) refraction (3) diffraction (4) total internal reflection

Last Answer : (4) total internal reflection Explanation: If the angle of incidence of light ray in the denser medium is greater than the critical angle of the concerned media pair, the light is not at all reflected in to the rarer medium but is totally reflected. This is known as 'total internal reflection'.

The phenomenon of change in direction of light when it passes from one medium to another is called - (1) Propagation (2) Reflection (3) Refraction (4) Dispersion

Description : The phenomenon of change in direction of light when it passes from one medium to another is called - (1) Propagation (2) Reflection (3) Refraction (4) Dispersion

Last Answer : (3) Refraction Explanation: Refraction is the change in direction of wave propagation due to a change in its transmission medium. Due to the change of medium, the phase velocity of the wave is changed but its frequency remains constant.

The phenomenon of change in direction of light when it passes from one medium to another is called (1) Propagation (2) Reflection (3) Refraction (4) Dispersion

Description : The phenomenon of change in direction of light when it passes from one medium to another is called (1) Propagation (2) Reflection (3) Refraction (4) Dispersion

Last Answer : Refraction

A light ray travelling from denser to rarer medium at an angle of incidence more than critical angle of concerned media pair suffers. (1) reflection (2) refraction (3) diffraction (4) total internal reflection

Description : A light ray travelling from denser to rarer medium at an angle of incidence more than critical angle of concerned media pair suffers. (1) reflection (2) refraction (3) diffraction (4) total internal reflection

Last Answer :  total internal reflection

When a beam of light enters one medium from another, which quantity will not change? a. Direction b. Speed c. Frequency d. Wavelength

Description : When a beam of light enters one medium from another, which quantity will not change? a. Direction b. Speed c. Frequency d. Wavelength

Last Answer : c. Frequency

Quantity that do not change when a beam of light enters on e medium to another. A. Frequency B. Wavelength C. Direction D. Speed

Description : Quantity that do not change when a beam of light enters on e medium to another. A. Frequency B. Wavelength C. Direction D. Speed

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When a beam of light enters one medium from another, which quantity will not change? ∙ a. Direction ∙ b. Speed ∙ c. Frequency ∙ d. Wavelength

Description : When a beam of light enters one medium from another, which quantity will not change? ∙ a. Direction ∙ b. Speed ∙ c. Frequency ∙ d. Wavelength

Last Answer : c. Frequency

The different angles of entry of light into an optical fiber when the diameter of the core is many times the wavelength of the light transmitter is known as ________. A. refraction B. sensor C. mode D. emitter

Description : The different angles of entry of light into an optical fiber when the diameter of the core is many times the wavelength of the light transmitter is known as ________. A. refraction B. sensor C. mode D. emitter

Last Answer : C. mode

.A beam of light is incident on a large block of glass. The index of refraction of the glass is greater than one. Is the wavelength of the light in the glass? A. Longer than B. Shorter than C. The same as the wavelength of the light in the air? D. None of above

Description : .A beam of light is incident on a large block of glass. The index of refraction of the glass is greater than one. Is the wavelength of the light in the glass? A. Longer than B. Shorter than C. The same as the wavelength of the light in the air? D. None of above

Last Answer : B. Shorter than

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Description : The absolute value of a signal's highest intensity is called………. A. Peak Amplitude B. Frequency C. Phase D. Both a and c

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Description : Which of the following is not caused by atmospheric refraction of light? (1) Sun appearing red at sunset (2) Twinkling of stars at night (3) Sun appearing higher in the sky than it actually is (4) Sun becoming visible two or three minutes before actual sunrise

Last Answer : (3) Sun appearing higher in the sky than it actually is Explanation: The twinkling of stars and variation in size of the Sun are due to atmospheric refraction of light. Besides, refraction is also ... higher or lower in the sky due to the changing position of the Earth relative to the Sun.

Which of the following is not caused by atmospheric refraction of light ? (1) Sun appearing red at sunset (2) Twinkling of stars at night (3) Sun appearing higher in the sky than it actually is (4) Sun becoming visible two or three minutes before actual sunrise

Description : Which of the following is not caused by atmospheric refraction of light ? (1) Sun appearing red at sunset (2) Twinkling of stars at night (3) Sun appearing higher in the sky than it actually is (4) Sun becoming visible two or three minutes before actual sunrise

Last Answer : Sun appearing higher in the sky than it actually is

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Description : The wavelength at which the peak of intensity of blackbody radiation Occurs – (1) increases with increase in temperature (2) decreases with increase in temperature (3) is the same at all temperatures (4) does not follow any pattern as temperature changes

Last Answer : (2) decreases with increase in temperature Explanation: According to Wien's displacement law, when the temperature of a blackbody radiator increases, the overall radiated energy increases. ... to its temperature. Shorter-wavelength (higher-frequency) light corresponds to higherenergy photons.

The wavelength at which the peak of intensity of blackbody radiation occurs (1) increases with increase in temperature (2) decreases with increase in temperature (3) is the same at all temperatures (4) does not follow any pattern as temperature changes

Description : The wavelength at which the peak of intensity of blackbody radiation occurs (1) increases with increase in temperature (2) decreases with increase in temperature (3) is the same at all temperatures (4) does not follow any pattern as temperature changes

Last Answer : decreases with increase in temperature

The sun appears red at sunrise and sunset while it appears white at noon because of _____ A. Refraction B. It is cooler at sunrise and at sunset C. Diffraction leading to red end of the spectrum reaching the earth D. Scattering of light due to dust particles and air molecules

Description : The sun appears red at sunrise and sunset while it appears white at noon because of _____ A. Refraction B. It is cooler at sunrise and at sunset C. Diffraction leading to red end of the spectrum reaching the earth D. Scattering of light due to dust particles and air molecules

Last Answer : ANSWER: D

The sun appears red at sunrise and sunset while it appears white at noon, because A. Of refraction B. It is cooler at sunrise and at sunset C. Of diffraction leading to red end of the spectrum reaching the earth. D. Of Scattering of light due to dust particles and air molecules?

Description : The sun appears red at sunrise and sunset while it appears white at noon, because A. Of refraction B. It is cooler at sunrise and at sunset C. Of diffraction leading to red end of the spectrum reaching the earth. D. Of Scattering of light due to dust particles and air molecules?

Last Answer : C. Of diffraction leading to red end of the spectrum reaching the earth.

When a light wave is reflected from a mirror, there is a change in its – (1) frequency (2) amplitude (3) wavelength (4) velocity

Description : When a light wave is reflected from a mirror, there is a change in its – (1) frequency (2) amplitude (3) wavelength (4) velocity

Last Answer : (2) amplitude Explanation: When a light wave is reflected from an object, it changes not only its amplitude but also its phase according to the properties of the object at a particular point. The velocity and momentum are just reversed in another direction.

Light has wavelength, frequency, and speed. Which, if any, of these quantities remains unchanged when light passes from a vacuum into a block of glass?

Description : Light has wavelength, frequency, and speed. Which, if any, of these quantities remains unchanged when light passes from a vacuum into a block of glass?

Last Answer : ANSWER: FREQUENCY

When light is traveling through a vacuum, what is the product of the light's wavelength and frequency equal to? w) speed of light x) Plank's constant y) momentum z) wave number

Description : When light is traveling through a vacuum, what is the product of the light's wavelength and frequency equal to? w) speed of light x) Plank's constant y) momentum z) wave number

Last Answer : ANSWER: W -- SPEED OF LIGHT

When a light wave is reflected from a mirror, there is a change in its (1) frequency (2) amplitude (3) wavelength (4) velocity

Description : When a light wave is reflected from a mirror, there is a change in its (1) frequency (2) amplitude (3) wavelength (4) velocity

Last Answer : amplitude

Decibel is the unit used for – (1) Speed of light (2) Intensity of heat (3) Intensity of sound (4) Radio wave frequency

Description : Decibel is the unit used for – (1) Speed of light (2) Intensity of heat (3) Intensity of sound (4) Radio wave frequency

Last Answer : (3) Intensity of sound Explanation: The decibel (abbreviated dB) is the unit used to measure the intensity of a sound. The decibel scale is a little odd because the human ear is incredibly ... of a physical quantity (usually power or intensity) relative to a specified or implied reference level.

When a certain beam of light falls upon a metal surface, it ejects photoelectrons from it. The number of photoelectrons ejected per second by the beam of light depends upon one of the following. Is it proportional to: w) the threshold frequency of the metal x) the work function of the metal y) the frequency of the beam z) the intensity of the beam

Description : When a certain beam of light falls upon a metal surface, it ejects photoelectrons from it. The number of photoelectrons ejected per second by the beam of light depends upon one of the following. Is it ... the work function of the metal y) the frequency of the beam z) the intensity of the beam

Last Answer : ANSWER: Z -- THE INTENSITY OF THE BEAM

The energy associated with one photon of a light beam is proportional to one of the following. Is it proportional to: w) the intensity of the light source from which it came x) the number of photons in the beam y) the frequency of the photon z) the speed of the photon

Description : The energy associated with one photon of a light beam is proportional to one of the following. Is it proportional to: w) the intensity of the light source from which it came x) the number of photons in the beam y) the frequency of the photon z) the speed of the photon

Last Answer : ANSWER: Y -- THE FREQUENCY OF THE PHOTON

Decibel is the unit used for (1) Speed of light (2) Intensity of heat (3) Intensity of sound (4) Radio wave frequency

Description : Decibel is the unit used for (1) Speed of light (2) Intensity of heat (3) Intensity of sound (4) Radio wave frequency

Last Answer : Intensity of sound

What is true for intensity of scattered light according to Rayleigh’s law? A. The intensity for scattering for light of largest wavelength more B. The light of smallest wavelength will be scattered more C. All the wavelengths are scattered equally D. Intensity of light is not affected by scattering

Description : What is true for intensity of scattered light according to Rayleigh's law? A. The intensity for scattering for light of largest wavelength more B. The light of smallest wavelength will be scattered ... C. All the wavelengths are scattered equally D. Intensity of light is not affected by scattering

Last Answer : B. The light of smallest wavelength will be scattered more

In reference with antireflection coating which of the following statement is true? A. Thickness of the film should be changed for light of same wavelength but different intensity B. Thickness of the film need not be changed for light of same wavelength but different intensity C. Thickness of the film should be increased for light of same wavelength but higher intensity D. Thickness of the film should be decreased for light of same wavelength but higher intensity

Description : In reference with antireflection coating which of the following statement is true? A. Thickness of the film should be changed for light of same wavelength but different intensity B. Thickness of ... D. Thickness of the film should be decreased for light of same wavelength but higher intensity

Last Answer : B. Thickness of the film need not be changed for light of same wavelength but different intensity

Resolution by any microscope is ULTIMATELY limited by the: a) curvature of the lenses b) wavelength of the light c) light intensity d) lens aberrations

Description : Resolution by any microscope is ULTIMATELY limited by the: a) curvature of the lenses b) wavelength of the light c) light intensity d) lens aberrations

Last Answer : ANSWER: B -- WAVELENGTH OF THE LIGHT

In the Tyndall Effect, the intensity of scattered radiation is inversely proportional to the fourth power of the wavelength. Which one of the following colors of light would exhibit the most intense Tyndall scattering? w) yellow x) green y) orange z) violet

Description : In the Tyndall Effect, the intensity of scattered radiation is inversely proportional to the fourth power of the wavelength. Which one of the following colors of light would exhibit the most intense Tyndall scattering? w) yellow x) green y) orange z) violet 

Last Answer : ANSWER: Z -- VIOLET 

A star appears twinkling in the sky because of – (1) scattering of light by atmosphere (2) reflection of light by atmosphere (3) refraction of light by atmosphere (4) diffraction of light by atmosphere

Description : A star appears twinkling in the sky because of – (1) scattering of light by atmosphere (2) reflection of light by atmosphere (3) refraction of light by atmosphere (4) diffraction of light by atmosphere

Last Answer : (3) refraction of light by atmosphere Explanation: A star appears twinkling in the sky because of refraction of light, by atmosphere. Light bends when it passes obliquely from one medium to another. This is called refraction of light.

A star appears twinkling in the sky because of (1) scattering of light by atmosphere (2) reflection of light by atmosphere (3) refraction of light by atmosphere (4) diffraction of light by atmosphere

Description : A star appears twinkling in the sky because of (1) scattering of light by atmosphere (2) reflection of light by atmosphere (3) refraction of light by atmosphere (4) diffraction of light by atmosphere

Last Answer : refraction of light by atmosphere

The speed of any mechanical wave as it propagates through a medium is dependent mainly on the A. frequency of the wave source B. wavelength C. period of the wave D. type of medium through which the wave travels E. amplitude

Description : The speed of any mechanical wave as it propagates through a medium is dependent mainly on the A. frequency of the wave source B. wavelength C. period of the wave D. type of medium through which the wave travels E. amplitude

Last Answer : D. type of medium through which the wave travels

Mirage is caused due to (a) total Internal Reflection of light by the various layers of air (b) illusion of the presence of water (c) result of refraction of light from a non-uniform medium (d) during sunny days when driving on a roadway

Description : Mirage is caused due to (a) total Internal Reflection of light by the various layers of air (b) illusion of the presence of water (c) result of refraction of light from a non-uniform medium (d) during sunny days when driving on a roadway

Last Answer : (a) total Internal Reflection of light by the various layers of air

An index of refraction less than one for a medium would imply A. That the speed of light in the medium is the same as the speed of light in vacuum B. That the speed of light in the medium is greater than the speed of light in vacuum C. Refraction is not possible D. Reflection is not possible

Description : An index of refraction less than one for a medium would imply A. That the speed of light in the medium is the same as the speed of light in vacuum B. That the speed of light in the ... greater than the speed of light in vacuum C. Refraction is not possible D. Reflection is not possible

Last Answer : B. That the speed of light in the medium is greater than the speed of light in vacuum

What is the wavelength of red light emitted by a helium-neon laser? w) 122 nanometers x) 633 nanometers y) 2.43 picometers z) 1.37 micrometers

Description : What is the wavelength of red light emitted by a helium-neon laser? w) 122 nanometers x) 633 nanometers y) 2.43 picometers z) 1.37 micrometers

Last Answer : ANSWER: X -- 633 NANOMETERS (actually 632.8 nm)

Which of the following colors of visible light has the longest wavelength? Is it: w) violet x) green y) yellow z) red

Description : Which of the following colors of visible light has the longest wavelength? Is it: w) violet x) green y) yellow z) red

Last Answer : ANSWER: Z -- RED

Radio channels are attractive medium because __________ a) Can penetrate walls b) Connectivity can be given to mobile user c) Can carry signals for long distance d) All of the mentioned

Description : Radio channels are attractive medium because __________ a) Can penetrate walls b) Connectivity can be given to mobile user c) Can carry signals for long distance d) All of the mentioned

Last Answer : d) All of the mentioned

Danger signals are generally red as red light – (1) is least bright (2) undergoes least deviation (3) has lowest velocity (4) gives comfort to eye

Description : Danger signals are generally red as red light – (1) is least bright (2) undergoes least deviation (3) has lowest velocity (4) gives comfort to eye

Last Answer : (2) undergoes least deviation Explanation: The primary reason why the colour red is used for danger signals is that red light is scattered the least by air molecules. The effect of scattering is inversely ... red which has the highest wavelength of all the colours we can see is scattered the least.