# Engineering Physics Questions and Answers – Tunnel Effect

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This set of Engineering Physics Multiple Choice Questions & Answers (MCQs) focuses on “Tunnel Effect”.

1. The transmission based on tunnel effect is that of a plane wave through a ____________
a) Circular Barrier
b) Opaque Object
c) Rectangular Barrier
d) Infinitely small barrier

Explanation: The transmission of a plane wave through a rectangular barrier is dependent on the tunnel effect. It is also called Rectangular potential barrier.

2. he particle has a finite, non-zero, potential for the region ____________
a) x > 0
b) x < 0
c) 0 < X < a
d) x > a

Explanation: The particle incident on the rectangular barrier has a finite and non-zero potential, when the particles lies between 0 and a.

3. In quantum mechanics, if the energy of the particle, E, is less than the energy required to enter a region, U, the particle is always reflected back.
a) True
b) False

Explanation: In Quantum Mechanics, even if E < U, there is a chance that the particle might tunnel through it. This concept is different from the classical mechanics.

4. Tunnel effect is notably observed in the case of ____________
a) X-rays
b) Gamma rays
c) Alpha Particles
d) Beta Particles

Explanation: The tunnel effect actually occurs, notably in the case of alpha particles emitted by certain radioactive nuclei. It has the energy of a few MeV.

5. The solution of Schrodinger wave equation for Tunnel effect is of the form ____________
a) Aeikx+ Beikx
b) Aeikx– Beikx
c) Aeikx+ Be-ikx
d) Aeikx– Be-ikx

Explanation: When the Schrodinger Wave equation is solved for the particle undergoing tunnel effect, the general solution of wave function is of the form: Aeikx+ Be-ikx.

6. The particle with wave function Aekx+ Be-kx represents ____________
a) Oscillating particle
b) Moving Particle
c) Probable Particle
d) No such wave function

Explanation: The given wave function does not oscillate and does not represent a moving particle. Its probability density is not zero, so there is a finite probability of finding a particle within the barrier.

7. Tunnel effect happens during nuclear fusion in stars.
a) True
b) False

Explanation: Tunnel effect plays an essential role in several physical phenomena, such as the nuclear fusion that occurs in main sequence stars like the Sun, tunnel diode, quantum computing, and in the scanning tunneling microscope.

8. Tunnel effect can be explained on the basis of ____________
a) Schrodinger’s Equation
b) Particle in a Box
c) Heisenberg’s uncertainty principle
d) De-Broglie Wavelength

Explanation: The tunnel effect can be understood in terms of the uncertainty principle. Using it, we can say that the particle must be able to enter the barrier, and once inside it, has the possibility of continuing on.

9. The expression for Transmission probability is ____________
a) e-kL
b) e-2kL
c) ekL
d) e2kL

Explanation: The transmission probability of a particle can be expressed as: e-2kL. It shows that the larger is L, smaller is the transmission probability.

10. In which of the following regions is E<V? a) A
b) B
c) C
d) None of the regions 