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Why photoelectric effect cannot be explained on the basis of wave nature of light? Give reasons.
Concept: Wave Nature of Matter
Write the basic features of photon picture of electromagnetic radiation on which Einstein’s photoelectric equation is based.
Concept: Einstein’s Equation - Particle Nature of Light
point out any two characteristic properties of photons on which Einstein’s photoelectric equation is based ?
Concept: Einstein’s Photoelectric Equation: Energy Quantum of Radiation
Briefly explain the three observed features which can be explained by Einstein’s photoelectric equation.
Concept: Einstein’s Photoelectric Equation: Energy Quantum of Radiation
State clearly how photoelectric equation is obtained using the photon pictu.re of electromagnetic radiation.
Concept: Dual Nature of Radiation
Write the three salient features observed in photoelectric effect which can be explained using this equation.
Concept: Dual Nature of Radiation
Answer the following question.
Define the term "Threshold frequency", in the context of photoelectric emission.
Concept: Electron Emission
Why it is the frequency and not the intensity of the light source that determines whether the emission of photoelectrons will occur or not? Explain.
Concept: Experimental Study of Photoelectric Effect
Which one of the following metals does not exhibit emission of electrons from its surface when irradiated by visible light?
Concept: Photoelectric Effect - Hallwachs’ and Lenard’s Observations
Read the following paragraph and answer the questions.
| The figure shows the variation of photoelectric current measured in a photocell circuit as a function of the potential difference between the plates of the photocell when light beams A, B, C and D of different wavelengths are incident on the photocell. Examine the given figure and answer the following questions: |
- Which light beam has the highest frequency and why?
- Which light beam has the longest wavelength and why?
- Which light beam ejects photoelectrons with maximum momentum and why?
Concept: Experimental Study of Photoelectric Effect
How will the de-Broglie wavelength associated with an electron be affected when the velocity of the electron decreases? Justify your answer.
Concept: Wave Nature of Matter
How would the stopping potential for a given photosensitive surface change if the intensity of incident radiation was decreased? Justify your answer.
Concept: Experimental Study of Photoelectric Effect
How would the stopping potential for a given photosensitive surface change if the frequency of the incident radiation were increased? Justify your answer.
Concept: Experimental Study of Photoelectric Effect
How will the de-Broglie wavelength associated with an electron be affected when the accelerating potential is increased? Justify your answer.
Concept: Wave Nature of Matter
What is the effect of threshold frequency and stopping potential on increasing the frequency of the incident beam of light? Justify your answer.
Concept: Experimental Study of Photoelectric Effect
Show that the radius of the orbit in hydrogen atom varies as n2, where n is the principal quantum number of the atom.
Concept: De Broglie’s Explanation of Bohr’s Second Postulate of Quantisation
Using Rutherford's model of the atom, derive the expression for the total energy of the electron in hydrogen atom. What is the significance of total negative energy possessed by the electron?
Concept: Alpha-particle Scattering and Rutherford’s Nuclear Model of Atom
Using Bohr's postulates of the atomic model, derive the expression for radius of nth electron orbit. Hence obtain the expression for Bohr's radius.
Concept: Bohr’s Model for Hydrogen Atom
Suppose you are given a chance to repeat the alpha-particle scattering experiment using a thin sheet of solid hydrogen in place of the gold foil. (Hydrogen is a solid at temperatures below 14 K.) What results do you expect?
Concept: Alpha-particle Scattering and Rutherford’s Nuclear Model of Atom
Define the distance of closest approach. An α-particle of kinetic energy 'K' is bombarded on a thin gold foil. The distance of the closest approach is 'r'. What will be the distance of closest approach for an α-particle of double the kinetic energy?
Concept: Alpha-particle Scattering and Rutherford’s Nuclear Model of Atom
