Dual Nature of Matter and Radiation

Photoelectric current from a given photocell will depend upon

If alpha, beta and gamma rays carry same momentum, which has the longest wavelength

The threshold frequency for a metallic surface corresponds to an energy of 6.2 eV, and the stopping potential for a radiation incident on this surface 5 V. The incident radiation lies in

The ionization energy of Li⁺⁺ is equal to

What is the energy of photon whose wavelength is 6840 Å?

A 200 W sodium street lamp emits yellow light of wavelength 0.6 µm. Assuming it to be 25% efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is

A source of light is placed at a distance of 50 cm from a photocell and the stopping potential is found to be V₀. If the distance between the light source and photocell is made 25 cm, the new stopping potential will be

A 5 watt source emits monochromatic light of wavelength 5000 Å. When placed 0.5 m away, it liberates photoelectrons from a photosensitive metallic surface. When the source is moved to a distance of 1.. m, the number of photoelectrons liberated will be reduced by a factor of

A beam of cathode rays is subjected to crossed Electric(E) and Magnetic fields(B). The fields are adjusted such that the beam is not deflected. The specific charge of the cathode rays is given by: (Where V is the potential difference between cathode and anode).

A particle of mass 1 mg has the same wavelength as an electron moving with a velocity of 3 x 10⁶ ms⁻¹. The velocity of the particle is: (mass of electron = 9.1 x 10⁻³¹ kg)

If threshold wavelength for sodium is 6800 Å, the work function will be

Photons of energy 6 eV are incident on a metal surface whose work function is 4 eV. The minimum kinetic energy of the emitted photo-electrons will be

The photoelectric threshold wavelength for potassium (work function being 2 eV) is

Light of frequency 8 x 10¹⁵ Hz is incident on a substance of photoelectric work function 6.125 eV. The maximum kinetic energy of the emitted photoelectron is

The velocity of radio-waves is 3 x 10⁵ km/s. The frequency corresponding to wavelength of 300 m is

The work function for aluminium is 4.125 eV. The cutoff wavelength for photoelectric effect for aluminium will be

Consider two particles of different masses. In which of the following situations the heavier of the two particles will have smaller de-Broglie wavelength?

The de-Broglie wavelength associated with an electron accelerated by a potential of 64 V is

When a metallic surface is illuminated with radiation of wavelength λ, the stopping potential is V. If the same surface is illuminating with radiation of wavelength 2λ, the stopping potential is V/4. The threshold wavelength for the metallic surface is

Photons with energy 5eV are incident on a cathode C in a photoelectric cell. The maximum energy of emitted photoelectrons is 2 eV. When photons of energy 6 eV are incident on C, no photoelectrons will reach the anode A, if the stopping potential of A relative to C is

When a light beam of frequency v is incident on a metal surface, photoelectrons are emitted. If these electrons describe a circle of radius r in a magnetic field of strength B, then the work function of the metal is

The work function of metals is in the range of 2 eV to 5 eV. Find which of the following wavelength of light cannot be used for photoelectric effect? (Consider, plank constant = 4 x 10⁻¹⁵ eVs, velocity of light = 3 x 10⁸ ms⁻¹)

The electrons are emitted in the photoelectric effect from a metal surface

When intensity of radiation is increased on a photosensitive plate, then

Rate of photoelectric emission is proportional to

For photoelectric emission to take place

The most important characteristic of electron in the production of X-rays is

what is the de-Broglie wavelength of the electron accelerated through a potential difference of 100V?

When the energy of the incident radiation is increased by 20%, the kinetic energy of the photoelectrons emitted from a metal surface increased from 0.5 eV to 0.8 eV. The work function of the metal is

Light of wavelength λᴀ and λʙ falls on two identical metal plates A and B respectively. The maximum kinetic energy of photoelectrons is Kᴀ and Kʙ respectively, then which one of the following relations is true?(λᴀ=2λʙ)

Penetrating power of X-rays does not depend on

The maximum kinetic energy of the photoelectrons depends only on

The lowest frequency of light that will cause the emission of photoelectrons from the surface of a metal (for which work function is 1.65 eV) will be

Light of two different frequencies whose photons have energies 1 eV and 2.5 eV respectively, successively illuminates a metal of work function 0.5 eV. The ratio of maximum kinetic energy of the emitted electron will be

When a charged oil drop moves upwards in an electric field, the electric force acting on the drop is

If the wavelength of incident light falling on a photosensitive material decreases, then

The potential difference applied to an X-ray tube is 5 kV and the current through it is 3.2 mA. The number of electrons striking the target per second is

The de-Broglie wavelength of an electron is the same as that of a 50 KeV X-ray photon. The ratio of the energy of the photon to the kinetic energy of the electron is (the energy equivalent of electron mass of 0.5 MeV)

The threshold wavelength for photoelectric effect of a metal is 6500 Å. The work function of the metal is approximately

Einstein’s photoelectric equation is

The speed of an electron having a wavelength of 10⁻¹⁰ m is

Photons of 5.5 eV energy fall on the surface of the metal emitting photoelectrons on maximum kinetic energy 4.0 eV. The stopping voltage required for these electrons is

The Davisson- Germer experiment is the direct evidence of

The additional energy that should be given to an electron to reduce its de-Broglie wavelength from 1nm to 0.5nm is

Maximum velocity of the photoelectron emitted by a metal is 1.8 x 10⁶ ms⁻¹. Take the value of specific charge of the electron is 1.8 x 10¹¹ C kg⁻¹. Then the stopping potential in volt is

The number of photons of wavelength of 540 nm emitted per second by an electric bulb of power 100 W is (given h = 6 x 10⁻³⁴ J-s)

Photocells convert

When radiation is incident on a photoelectron emitter, the stopping potential is found to be 9 volt. If e/m for the electron is 1.8×10¹¹ Ckg⁻¹, the maximum velocity of the ejected electrons is

Energy of photon whose frequency is 10¹² MHz will be

Maximum kinetic energy of electrons emitted in photoelectric effect increases when

In photoelectric effect, the photoelectric current

When ultraviolet rays are incident on metal plate, then photoelectric effect does not occur. It occur by the incidence of

If particles are moving with same velocity, then maximum de Broglie wavelength will be for

what should be the velocity of an electron so that its momentum becomes equal to that of a photon of wavelength 5200 Å?

Which of the following is or the property of a cathode ray

The de-Broglie wavelength of an electron moving with a velocity 1.5 x 10⁸ ms⁻¹ is equal to that of a photon. The ratio of the kinetic energy of the electron to the energy of the photon is

The threshold frequency for a certain photosensitive metal is ν₀. When it is illuminated by light of frequency ν=2ν₀, the maximum velocity of photoelectrons is ν₀. What will be the maximum velocity of the photoelectrons when the same metal is illuminated by light of frequency ν=5ν₀?

X-ray beam can be deflected by

The name of ions knocked out from the hot surface is

What is the difference between soft and hard X-ray?

Monochromatic light of frequency 6.0 x 10¹⁴ Hz is produced by a laser. The power emitted is 2 x 10⁻³ ω. The number of photons emitted, on the average, by the sources per second is

In a photoelectric effect experiment, the slope of the graph between the stopping potential and the incident frequency will be

The work function of sodium is 2.3 eV. The threshold wavelength of sodium will be

Which of the following phenomenon exhibited the particle nature of light?

The ratio of specific charge of an α-particle to that of a proton is

The number of photo electrons emitted for light of a frequency v (higher than the threshold frequency v₀) is proportional to:

Monochromatic light of wavelength 667 nm is produced by a helium neon laser. The power emitted is 9 mW. The number of photons arriving per second on the average at a large irradiated by this beam is:

X-rays when incident on a metal

Source S₁ is producing, 10¹⁵ photons per second of wavelength 5000 Å. Another source S₂ is producing 1.02 x 10¹⁵ photons per second of wavelength 5100Å Then, (power of S₂) (power of S₁) is equal to:

The minimum wavelength of X-rays produced in a Collidge tube operated at potential difference of 40 kV is

The potential difference that must be applied to stop the fastest photoelectrons emitted by a nickel surface, having work function 5.01 eV, when ultraviolet light of 200 nm falls on it, must be:

Order of e/m ratio of proton, α-particle and electron is

Photoelectric emission occurs only when the incident light has more than a certain minimum

The work function of a substance is 4.0 eV. The longest wavelength of light that can cause photoelectron emission from this substance is approximately

In the Davisson and Germer experiment, the velocity of electrons emitted from the electron gun can be increased by

Light of two different frequencies whose photons have energies 1 eV and 2.5 eV respectively illuminate a metallic surface whose work function is 0.5 eV successively. Ratio of maximum speed of emitted electrons will be

Electrons used in an electron microscope are accelerated by a voltage of 25 kV. If the voltage is increased associated to 100 kV then the de-Broglie wavelength associated with the electrons would

In photoelectric emission process from a metal of work function, 1.8 eV, the kinetic energy of most energetic electrons is 0.5 eV. The corresponding stopping potential is

The threshold frequency for a photosensitive metal is 3.3 x 10¹⁴ Hz. If light of frequency 8.2 x 10¹⁴ Hz incident on this metal, the cut-off voltage for the photoelectric emission is nearly

The work function for metals A,B are C are respectively 1.92 eV, 2.0 eV and 5 eV. According to Einstein’s equation the metals which will emit photoelectrons for a radiation of wavelength 4100 Å is/are

Monochromatic radiation emitted when electron on hydrogen atom jumps from first excited to the ground state irradiates a photosensitive material. he stopping potential is measured to be 3.57 V. The threshold frequency of the materials is:

When light of wavelength 300 nm falls on a photoelectric emitter, photoelectrons are liberated. For another emitter, light of wavelength 600 nm is sufficient for liberating photoelectrons. The ratio of the work function of the two emitters is

If the momentum of electron is changed by P, then the de-Broglie wavelength associated with it changes by 0.5%. The initial momentum of electron will be:

Maximum velocity of the photoelectrons emitted by a metal surface is 1.2 x 10⁶ ms⁻¹. Assuming the specific charge of the electron to be 1.8 x 10¹¹ C kg⁻¹, the value of the stopping potential in volt will be

Two radiations of photons energies 1 eV and 2.5 eV, successively illuminate a photosensitive metallic surface of work function 0.5 eV. The ratio of the maximum speeds of the emitted electrons is:

For photoelectric emission from certain metal the cut-off frequency is v. If radiation of frequency 2v impinges on the metal plate, the maximum possible velocity of the emitted electron will be (m is the electron mass)

The wavelength λₑ of an electron and λp of a photon are of same energy E are related by

The photoelectric threshold frequency of a metal is ν. When light of frequency 4ν is incident on the metal, the maximum kinetic energy of the emitted photoelectron is

The de-Broglie wavelength of neutron in thermal equilibrium at temperature T is

When photons of energy hν are incident on the surface of photosensitive material of work function hν₀, then

α-particles, deuterons and protons of same energy are moving in a perpendicular magnetic field. The ratio of diameters of their circular paths will be

The wavelength of the matter wave is independent of

Which of the following are mechanical waves?

We get Balmer series when electron comes from

In a discharge tube ionization of enclosed gas is produced due to collisions between

The momentum of a photon of energy 1 MeV in kg m/s will be

The time by a photoelectron to come out after the photon strikes is approximately

The Principle of LASER action involves

The electromagnetic theory of light failed to explain

If the radioactive decay constant of radium is 1.07 x 10⁻⁴ year⁻¹, then its half-life is approximately

If the velocity of an electron increases, then its de Broglie wavelength will

If h is Planck’s constant, the momentum of a photon of wavelength 0.01 Å is

What is the energy of He⁺ electron in first orbit?

Photon of frequency ν has a momentum associated with it. If c is the velocity of light, the momentum is

In the phenomenon of electric discharge through gases at low pressure, the coloured glow in the tube appears as a result of

When a piece of metal is illuminated by a monochromatic light of wavelength λ, then stopping potential is 3Vs. When same surface is illuminated by light of wavelength 2λ, then stopping potential becomes Vs. The value of threshold wavelength for photoelectric emission will be

The maximum kinetic energy of emitted electrons in a photoelectric effect does not depend upon

If an electron and a proton have the same de-Broglie wavelength, then the kinetic energy of the electron is

The threshold wavelength for photoelectric emission from a material is 4800 Å. Photoelectrons will be emitted from the material, when it is illuminated with light from a

Which phenomenon best supports the theory that matter has a wave nature?