Balbharati solutions for Physics 12th Standard HSC Maharashtra State Board chapter 14 - Dual Nature of Radiation and Matter [Latest edition]

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A photocell is used to automatically switch on the street lights in the evening when the sunlight is low in intensity. Thus it has to work with visible light. The material of the cathode of the photocell is

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Polychromatic (containing many different frequencies) radiation is used in an experiment on the photoelectric effect. The stopping potential

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An electron, a proton, an α-particle, and a hydrogen atom are moving with the same kinetic energy. The associated de Broglie wavelength will be longest for

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If N_Red and N_Blue are the numbers of photons emitted by the respective sources of equal power and equal dimensions in unit time, then

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The equation E = pc is valid

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What is the photoelectric effect?

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Can microwaves be used in the experiment on photoelectric effect?

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Is it always possible to see the photoelectric effect with a red light?

Using the values of work function given in the following table, tell which metal will require the highest frequency of incident radiation to generate photocurrent. Typical values of work function for some common metals

What do you understand by the term wave-particle duality? Where does it apply?

Explain the inverse linear dependence of stopping potential on the incident wavelength in a photoelectric effect experiment.

It is observed in an experiment on the photoelectric effect that an increase in the intensity of the incident radiation does not change the maximum kinetic energy of the electrons. Where does the extra energy of the incident radiation go? Is it lost? State your answer with explanatory reasoning.

Explain what you understand by the de Broglie wavelength of an electron. Will an electron at rest have an associated de Broglie wavelength? Justify your answer.

State the importance of Davisson and Germer experiment.

What will be the energy of each photon in monochromatic light of frequency 5 ×10¹⁴Hz?

The threshold wavelength of tungsten is 2.76 x 10^-5 cm.
(a) Explain why no photoelectrons are emitted when the wavelength is more than 2.76 x 10^-5 cm.
(b) What will be the maximum kinetic energy of electrons ejected in each of the following cases

(i) if ultraviolet radiation of wavelength λ = 1.80 × 10^-5 cm and
(ii) radiation of frequency 4 x 10¹⁵ Hz is made incident on the tungsten surface?

Photocurrent recorded in the microammeter in an experimental setup of the photoelectric effect vanishes when the retarding potential is more than 0.8 V if the wavelength of incident radiation is 4950 Å. If the source of incident radiation is changed, the stopping potential turns out to be 1.2 V. Find the work function of the cathode material and the wavelength of the second source.

Radiation of wavelength 4500 Å is incident on a metal having work function 2.0 eV. Due to the presence of a magnetic field B, the most energetic photoelectrons emitted in a direction perpendicular to the field move along a circular path of radius 20 cm. What is the value of the magnetic field B?

Given the following data for incident wavelength and the stopping potential obtained from an experiment on the photoelectric effect, estimate the value of Planck's constant and the work function of the cathode material. What is the threshold frequency and corresponding wavelength? What is the most likely metal used for emitter?

Calculate the wavelength associated with an electron, its momentum and speed when it is accelerated through a potential of 54 V.

Calculate the wavelength associated with an electron, its momentum and speed when it is moving with the kinetic energy of 150 eV.

The de Broglie wavelengths associated with an electron and a proton are the same. What will be the ratio of (i) their momenta (ii) their kinetic energies?

Two particles have the same de Broglie wavelength and one is moving four times as fast as the other. If the slower particle is an α-particle, what are the possibilities for the other particle?

What is the speed of a proton having de Broglie wavelength of 0.08 Å?

In nuclear reactors, neutrons travel with energies of 5 × 10^-21J. Find their speed and wavelength.

Find the ratio of the de Broglie wavelengths of an electron and a proton when both are moving with the (a) same speed, (b) the same kinetic energy, and (c) the same momentum. State which of the two will have a longer wavelength in each case.