THEORY QUESTIONS

  1. Define the terms work function and threshold frequency? Show the photoelectric effect is a frequency dependence phenomenon and not intensity dependent one.
  2. Derive the expression for the energy eigen values and eigen function in one dimension for a particle confined to one-dimensional infinite potential well.
  3. How was de Broglie's hypothesis confirmed mathematically for electron matter waves?
  4. Explain how experimentally confirmed the existence of matter waves by the diffraction phenomena?
  5. Prove that matter waves can travel faster than light?
  6. Derive an expression for the time independent Schrödinger wave equation.
  7. Derive expression for de Broglie wavelength in terms of kinetic energy of the particle.
  8. Differentiate between classical logic gates and quantum logic gates. Write any two applications of quantum computers.
  9. What is quantum cryptography? What is the role of key in cryptography- Illustrate with one example
  10. What is quantum computing? Explain quantum teleportation.

NUMERICAL PROBLEMS

  1. Calculate threshold frequency and work function for a copper surface irradiated with wavelength of 1849 Å and stopping potential is 2.7V.
  2. Find the energy values of an electron in the ground state and the first two excited states of a 1-D potential box of infinite height, width 2Å.
  3. If the velocity of the electron in the electron microscope is 1.6 × 106 ms–1, calculate de Broglie wavelength associated with this electron.
  4. Calculate de-Broglie wavelength associated with a proton moving with a velocity equal to 1/20 th of velocity of light?(Mass of the proton: 1.6726 x 10-27 kg)
  5. A particle is confined to an infinite potential well of width ‘L’. Calculate the probability and energy of the particle between x=0 and x=L/4 in the first excited state. Find the least energy of an electron moving in the dimension in an infinitely high potential box of width 1Å, given mass of the electron 9.11×10-31 kg and h =6.63×10-34 J.s.
  6. Find the de Broglie wavelength associated with an electron accelerated through a potential difference of 1600 V.