The principle of emission of electrons from a metal surface, under the influence of light is known as

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The principle of emission of electrons from a metal surface, under the influence of light is known as Photo electric emission.

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The process, whereby electrons gain sufficient energy to be released from the surface of a thin, heated metal plate, is known as _____________. A. photo electric emission B. secondary emission C. thermionic emission D. regressive emission

Description : The process, whereby electrons gain sufficient energy to be released from the surface of a thin, heated metal plate, is known as _____________. A. photo electric emission B. secondary emission C. thermionic emission D. regressive emission

Last Answer : Answer: C

When a metal is heated in a flame, the electrons absorb energy and jump to higher energy state. On coming back to the lower energy state, they emit light, which we can observe in - (1) Raman spectra (2) Absorption spectra (3) Emission spectra (4) Fluorescence

Description : When a metal is heated in a flame, the electrons absorb energy and jump to higher energy state. On coming back to the lower energy state, they emit light, which we can observe in - (1) Raman spectra (2) Absorption spectra (3) Emission spectra (4) Fluorescence

Last Answer : (3) Emission spectra Explanation: When a metal atom is strongly heated, its electrons absorb the heat energy and jump to a higher energy level. When the electron returns to its original position it ... to the energy the electron has released at each stage °fits fall back to its original state.

When a metal is heated in a flame, the electrons absorb energy and jump to higher energy state. On coming back to the lower energy siate, they emit light, which we can observe in (1) Raman spectra (2) Absorption spectra (3) Emission spectra (4) Fluorescence

Description : When a metal is heated in a flame, the electrons absorb energy and jump to higher energy state. On coming back to the lower energy siate, they emit light, which we can observe in (1) Raman spectra (2) Absorption spectra (3) Emission spectra (4) Fluorescence

Last Answer : Emission spectra

The emission of number of photo electrons depends upon a) The colour of the body b) The frequency of incident light c) The intensity of light d) All of the above

Description : The emission of number of photo electrons depends upon a) The colour of the body b) The frequency of incident light c) The intensity of light d) All of the above

Last Answer : c) The intensity of light

The phenomenon of ejection of electrons from the metal surface when a light of suitable frequency falls on it is called

Description : The phenomenon of ejection of electrons from the metal surface when a light of suitable frequency falls on it is called

Last Answer : Photoelectric effect

A substance emits energy which is detected as a line emission in the visible region using a spectroscope. The origin of this energy is (a) Vibrational energy of the molecules (b) Rotational energy of the molecules (c) Energy of orbital electrons (d) Energy of protons in the nucleus.

Description : A substance emits energy which is detected as a line emission in the visible region using a spectroscope. The origin of this energy is (a) Vibrational energy of the molecules (b) Rotational energy of the molecules (c) Energy of orbital electrons (d) Energy of protons in the nucleus.

Last Answer : Ans:(c)

(3) reflection of light due to the presence of free electrons Explanation: Lustre (or luster) is the way light interacts with the surface of a crystal, rock, or mineral. The word traces its origins back to the latin lux, meaning "light", and generally implies radiance, gloss, or brilliance. Metals in general have high electrical conductivity, high thermal conductivity, and high density. Typically they are malleable and ductile, deforming -under stress without cleaving.

Description : (3) reflection of light due to the presence of free electrons Explanation: Lustre (or luster) is the way light interacts with the surface of a crystal, rock, or mineral. The word ... conductivity, and high density. Typically they are malleable and ductile, deforming -under stress without cleaving.

Last Answer : Cloud is a colloidal dispersion of – (1) Air in a dispersion medium of water (2) Fog in a dispersion medium of water (3) Mist in a dispersion medium of air (4) Water drops in a dispersion medium of air

The basic operating principle of a transformer is attributed to ______________. A. electromagnetic induction B. variance of a conductor in a magnetic field C. mutual reaction D. thermionic emission

Description : The basic operating principle of a transformer is attributed to ______________. A. electromagnetic induction B. variance of a conductor in a magnetic field C. mutual reaction D. thermionic emission

Last Answer : Answer: A

The law that states “When visible light of high frequency electromagnetic radiation illuminates a metallic surface, electrons are emitted” is known as ____________. ∙ A. Einstein law of photon ∙ B. Marconi’s law ∙ C. Maxwell’s law ∙ D. Plank’s law

Description : The law that states “When visible light of high frequency electromagnetic radiation illuminates a metallic surface, electrons are emitted” is known as ____________. ∙ A. Einstein law of photon ∙ B. Marconi’s law ∙ C. Maxwell’s law ∙ D. Plank’s law

Last Answer : D. Plank’s law

Many living organisms exhibit the unique property of producing visible light. The compound that is oxidized with subsequent light emission is usually referred to as luciferin. What is the enzyme which catalyzes the reaction known as?

Description : Many living organisms exhibit the unique property of producing visible light. The compound that is oxidized with subsequent light emission is usually referred to as luciferin. What is the enzyme which catalyzes the reaction known as?

Last Answer : ANSWER: Luciferase

The ejection of electrons when a metal surface is irradiated is called (a) Black body radiation (b) Photoelectric effect (c) Zeeman effect (d) Atomic spectrum

Description : The ejection of electrons when a metal surface is irradiated is called (a) Black body radiation (b) Photoelectric effect (c) Zeeman effect (d) Atomic spectrum

Last Answer : Ans:(b)

Metal are good conductors, because (1) they contain free electrons (2) the molecules in them are very close to each other (3) the molecules in them collide very freely (4) they contain reflecting surface

Description : Metal are good conductors, because (1) they contain free electrons (2) the molecules in them are very close to each other (3) the molecules in them collide very freely (4) they contain reflecting surface

Last Answer : they contain free electrons

Form the hot metal surface electrons escape because

Description : Form the hot metal surface electrons escape because   (A) of change of state from metal to gas due to heat. (B) of change of state from gas to metal (C) the energy supplied is greater than the work function (D) the energy is greater than Fermi level

Last Answer : Form the hot metal surface electrons escape because the energy supplied is greater than the work function

A nuclide of an alkaine earth metal undergoes radioactive deacy by emission of the `alpha-` particles in sucession. The group of the periodic tablle t

Description : A nuclide of an alkaine earth metal undergoes radioactive deacy by emission of the `alpha-` particles in sucession. The group of the periodic tablle t

Last Answer : A nuclide of an alkaine earth metal undergoes radioactive deacy by emission of the `alpha-` particles in ... 6th group C. 14 th group D. 16th group

Cathode rays when obstructed by metal cause emission of - (1) γ – ray (2) X – ray (3) α – ray (4) β – ray

Description : Cathode rays when obstructed by metal cause emission of - (1) γ – ray (2) X – ray (3) α – ray (4) β – ray

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Pollution by particulate matter emission in the atmosphere does not take place during metal (A) Grinding (B) Machining(C) Cutting(D) Polishing

Description : Pollution by particulate matter emission in the atmosphere does not take place during metal (A) Grinding (B) Machining (C) Cutting (D) Polishing

Last Answer : (D) Polishing

State the different modes of electron emission in metal. Explain any two modes of emission.

Description : State the different modes of electron emission in metal. Explain any two modes of emission.

Last Answer : Different modes of electron emission in metal - 1. Thermionic emission 2. Photo electric emission. 3. Field emission. 4. Secondary emission. Mode of Emission  1. Thermionic emission. ... (GaP)  Application: Electron multiplier tubes, Special amplifying tubes, Computer memory tubes. 

A uniform cylinder of weight W is rolling while slipping on a rough horizontal surface under the influence of a horizontal force. The force of friction between the cylinder and the surface is a.Proportional to the coefficient of static friction b.Proportional to the coefficient of dynamic friction c.Indeterminate d.Determinate but depends on the acceleration of the cylinder e.None of the above

Description : A uniform cylinder of weight W is rolling while slipping on a rough horizontal surface under the influence of a horizontal force. The force of friction between the cylinder and the surface is a. ... c.Indeterminate d.Determinate but depends on the acceleration of the cylinder e.None of the above

Last Answer : c. Indeterminate

A uniform cylinder of weight W is rolling while slipping on a rough horizontal surface under the influence of a horizontal force. The force of friction between the cylinder and the surface is a.Indeterminate b.Proportional to the coefficient of dynamic friction c.Determinate but depends on the acceleration of the cylinder d.107 dynes e.Proportional to the coefficient of static friction

Description : A uniform cylinder of weight W is rolling while slipping on a rough horizontal surface under the influence of a horizontal force. The force of friction between the cylinder and the surface is a. ... on the acceleration of the cylinder d.107 dynes e.Proportional to the coefficient of static friction

Last Answer : c. Determinate but depends on the acceleration of the cylinder

The rate of emission of radiation by a body does not depend upon the (A) Wavelength of radiation (B) Surface temperature of the body (C) Nature of the surface (D) Shape and porosity of the body

Description : The rate of emission of radiation by a body does not depend upon the (A) Wavelength of radiation (B) Surface temperature of the body (C) Nature of the surface (D) Shape and porosity of the body

Last Answer : (D) Shape and porosity of the body

The rate of emission of radiation by a body does not depend upon the (A) Wavelength of radiation (B) Surface temperature of the body (C) Nature of the surface (D) Shape and porosity of the body

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Last Answer : (D) Shape and porosity of the body

Which one of the following statements is correct? (A) During the day, earth reflects solar radiation (B) During the day, earth reflects both solar radiations the emission from its surface (C) During the night, earth emits radiation from its surface (D) All of these

Description : Which one of the following statements is correct? (A) During the day, earth reflects solar radiation (B) During the day, earth reflects both solar radiations the emission from its surface (C) During the night, earth emits radiation from its surface (D) All of these

Last Answer : Answer: Option D

“When visible light of high frequency electromagnetic radiation illuminates a metallic surface, electrons are emitted”

Description : “When visible light of high frequency electromagnetic radiation illuminates a metallic surface, electrons are emitted”

Last Answer : Plank’s law

A space ship traveling toward Mars at 0.6 times the speed of light c shoots an ELECTRON beam at Mars. If the electrons travel at 0.6 c RELATIVE TO THE SPACE SHIP, at what speed do the electrons impact the surface of Mars? w) 0.6 c x) 0.88 c y) 1.2 c z) 1.34 c

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How did Lyell's principle of geology influence Darwin?

Description : How did Lyell's principle of geology influence Darwin?

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The principle professional competence and due care imposes which of the following obligations on professional accountants? a. To maintain professional knowledge and skill at the level required to ensure that a client or employer receives competent professional service. b. To comply with relevant laws and regulations and avoid any action that discredits the profession. c. Not to override or compromise his professional or business judgment because of bias, conflict of interest or undue influence of others. d. To be fair and truthful.

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Last Answer : To maintain professional knowledge and skill at the level required to ensure that a client or employer receives competent professional service.

The principle of Professional behavior requires a CPA to: a. Perform professional services with due care, competence and diligence. b. Be straightforward and honest in performing professional servicesc. Act in a manner consistent with thegood reputation of the professionand refrain from any conduct whichmight bring discredit to theprofession.d. Be fair and should not allow prejudice orbias, conflict of interest or influence ofothers to override objectivity or affecthis professional or business judgments.

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Last Answer : Act in a manner consistent with the good reputation of the profession and refrain from any conduct which might bring discredit to the profession

The principle of professional behavior requires a CPA to a. Be straightforward and honest in performing professional services. b. Perform professional services with due care, competence and diligence.c. Be fair and should not allow prejudice or bias, conflict of interest or influence of others to override objectivity. d. Act in a manner consistent with the good reputation of the profession and refrain from any conduct which might bring discredit to the profession

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Muller Breslau's principle for obtaining influence lines is applicable to (i) Trusses (ii) Statically determinate beams and frames (iii) Statically indeterminate structures, the material of which is elastic and follows Hooke's law (iv) Any statically indeterminate structure The correct answer is (A) (i), (ii) and (iii) (B) (i), (ii) and (iv) (C) (i) and (ii) (D) Only (i)

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An element used in semiconductors whose atoms have three valence electrons is

Last Answer : An element used in semiconductors whose atoms have three valence electrons is An acceptor.

The mercury and sodium street lamps light up because of – (1) Atomic emission (2) Atomic absorption (3) Electron emission (4) Electron absorption

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Last Answer : (1) Atomic emission Explanation: The light in sodium vapour lamp and mercury vapour lamp is, because of electron emission. In case of Sodium Lamps, filaments of the lamp sputter ... energy levels and the electrons thus excited relax by emitting the characteristic monochromatic bright yellow light.

The sky appears blue because of – (1) Atmospheric water vapour (2) Scattering of light (3) Reflection on sea water (4) Emission of blue wavelength by the sun

Description : The sky appears blue because of – (1) Atmospheric water vapour (2) Scattering of light (3) Reflection on sea water (4) Emission of blue wavelength by the sun

Last Answer : (2) Scattering of light Explanation: The sky is blue because the molecules in the air scatter light in the higher wavelengths (that is, the blue light), while lower wavelength light (that is ... reflected down from the scattering is blue, therefore a blue sky. This is called Rayleigh scattering.

Stars appear twinkling because of ______ of light. (1) Reflection (2) Scattering (3) Emission (4) Absorption

Description : Stars appear twinkling because of ______ of light. (1) Reflection (2) Scattering (3) Emission (4) Absorption

Last Answer : (2) Scattering Explanation: The stars' light must travel through the Earth's multi-layered atmosphere, and as it does so it is refracted (bent) multiple times and in random directions. The phenomenon of ... star wink as though it is in motion. It is this action that our eyes translate as twinkling.

LED stands for _________ A. Low Emission Display B. Liquid Emitting Display C. Less Emitting Diode D. Light Emitting Diode

Description : LED stands for _________ A. Low Emission Display B. Liquid Emitting Display C. Less Emitting Diode D. Light Emitting Diode

Last Answer : D. Light Emitting Diode

Emission of light in the visible region after absorbing certain electromagnetic radia- tions is called?

Description : Emission of light in the visible region after absorbing certain electromagnetic radia- tions is called?

Last Answer : Photoluminescence

Absorption of light of one wave length by a substance and the re-emission of light of greater wavelength is called?

Description : Absorption of light of one wave length by a substance and the re-emission of light of greater wavelength is called?

Last Answer : Fluorescence

The first laser emitted a. Pulses of 694 nm red light b. A continuous red beam c. Pulses of white light from a helical flashlamp d. Spontaneous emission

Description : The first laser emitted a. Pulses of 694 nm red light b. A continuous red beam c. Pulses of white light from a helical flashlamp d. Spontaneous emission

Last Answer : a. Pulses of 694 nm red light

Which of the following contributes to the broadening of laser emission bandwidth? a. Doppler shift of moving atoms and molecules b. Amplification within the laser medium c. Coherence of the laser light d. Optical pumping of the laser transition

Description : Which of the following contributes to the broadening of laser emission bandwidth? a. Doppler shift of moving atoms and molecules b. Amplification within the laser medium c. Coherence of the laser light d. Optical pumping of the laser transition

Last Answer : a. Doppler shift of moving atoms and molecules

Laser light is ______ emission. a. Coherent b. Stimulated c. Spontaneous d. Coherent and stimulated

Description : Laser light is ______ emission. a. Coherent b. Stimulated c. Spontaneous d. Coherent and stimulated

Last Answer : d. Coherent and stimulated

Which term describes the emission of light by a living organism? A. Natural light B. Bioluminescence (Answer)

Description : Which term describes the emission of light by a living organism? A. Natural light B. Bioluminescence (Answer)

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The blueness of the sky is mainly due to -------? A. The scattering of sunlight by air molecules (Answer) B. The presence of water vapor C. Absorption of blue light by the air D. Emission of blue light by the atmosphere

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Last Answer : A. The scattering of sunlight by air molecules (Answer)

A photochemical reaction is(A) Accompanied with emission of light (B) Catalysed by light (C) Initiated by light (D) All (A), (B) & (C)

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Last Answer : (C) Initiated by light

A photochemical reaction is __________ light. (A) Initiated by (B) Accompanied with emission of (C) Catalysed by (D) Used to convert heat energy into

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A pn-junction diode emits light by spontaneous emission ∙ A. LED ∙ B. APD ∙ C. PIN

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Last Answer : A. LED

They wrote a paper describing how it was possible to use stimulated emission for amplifying light waves (laser) as well as microwaves (maser). ∙ A. Theodore Maiman ∙ B. KC Kao and GA Bockham ∙ C. Charles Townes and Arthur Schawlow ∙ D. Kapron, Keck and Maurer

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Last Answer : C. Charles Townes and Arthur Schawlow

____ is a light that can be coherent ∙ a. Spontaneous emission ∙ b. Monochromatic and in-phase ∙ c. Narrow beam divergence ∙ d. Monochromatic

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Last Answer : ∙ b. Monochromatic and in-phase

The first laser emitted ∙ a. Pulses of 694 nm red light ∙ b. A continuous red beam ∙ c. Pulses of white light from a helical flash lamp ∙ d. Spontaneous emission

Description : The first laser emitted ∙ a. Pulses of 694 nm red light ∙ b. A continuous red beam ∙ c. Pulses of white light from a helical flash lamp ∙ d. Spontaneous emission

Last Answer : ∙ a. Pulses of 694 nm red light

Which of the following contributes to the broadening of laser emission bandwidth? ∙ a. Doppler shift of moving atoms and molecules ∙ b. Amplification within the laser medium ∙ c. Coherence of the laser light ∙ d. Optical pumping of the laser transition

Description : Which of the following contributes to the broadening of laser emission bandwidth? ∙ a. Doppler shift of moving atoms and molecules ∙ b. Amplification within the laser medium ∙ c. Coherence of the laser light ∙ d. Optical pumping of the laser transition

Last Answer : Doppler shift of moving atoms and molecules

Laser light is ______ emission. ∙ a. Coherent ∙ b. Stimulated ∙ c. Spontaneous ∙ d. Coherent and stimulated

Description : Laser light is ______ emission. ∙ a. Coherent ∙ b. Stimulated ∙ c. Spontaneous ∙ d. Coherent and stimulated

Last Answer : ∙ d. Coherent and stimulated

LASER stands for: a. Light Amplification by Simulated Emission of Radiation b. Light Amplification by Stimulated Emission of Radiation c. Light Amplification by Simulated Emitted Rays d. Light Amplification by Stimulated Emitted Rays

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Last Answer : b. Light Amplification by Stimulated Emission of Radiation