Objective Type Questions on Physics
1- The physical quantity that has the same dimension as the action S in Hamilton’s principle is
(A) Torque
(B) Orbital angular momentum
(C) Energy
(D) Linear momentum
2- Identify which one is a first order phase transition?
(A) A liquid to gas transition at its critical temperature.
(B) A metal to superconductor transition in the absence of a magnetic field.
(C) A liquid to gas transition close to its triple point.
(D) A paramagnetic to ferromagnetic transition in the absence of a magnetic field.
3- If light is incident at Brewster angle on a glass slab results in
(A) The production of circularly polarised light in reflection.
(B) The production of plane polarised light in reflection
(C) The production of circularly polarised lights in transmission.
(D) Total internal reflection of light
4- Choose the incorrect statement:
(A) The net charge of a p−type semiconductor is positive.
(B) Silicon is an indirect band gap semiconductor.
(C) The holes and electrons have different mobilities in a semiconductor.
(D) In an n-type semiconductor, the Fermi level lies closer to the conduction band
5- A diode that has a negative resistance characteristic is the
(A) Zener diode
(B) Laser diode
(C) Tunner diode
(D) Schottky diode
6- The order of magnitude of the energy band gap of a typical semiconductor is
(A) 1 meV
(B) 1 eV
(C) 1 keV
(D) 1 MeV
7- Two particles are said to be distinguishable when
(A) their total wave-function is symmetric under particle exchange
(B) they have overlapping wave-packets
(C) the average distance between them is large compared to their de-Broglie wavelength
(D) the average distance between them is small compared to their de-Broglie wavelength
8- The electric flux through any closed surface is measure of
(A) Total charge, both inside and outside the surface
(B) Total charge at the surface
(C) The total charge outside the surface
(D) The total charge inside the surface
9- Which one of the following diodes work on the principle of negative resistance?
(A) Photodiode
(B) Gunn diode
(C) Light-emitting diode
(D) Schottky diode
10- Which of following is not the part of a lock-in amplifier?
(A) Small signal amplifier
(B) Differentiator
(C) Integrator
(D) Phase sensitive detector
11- Phase curve of a freely falling body under gravity is
(A) Stable star
(B) Stable node
(C) Hyperbola
(D) Ellipse
12- Phase space trajectory of a one-dimensional simple harmonic oscillator is
(A) Cycloid
(B) Ellipse
(C) Parabola
(D) Hyperbola
13- When a monoatomic gas atom is placed in a uniform electric field E, the displacement of the nucleus is proportional to:
(A) 2E
(B) E
(C) 1/E
(D) 1/2E
14- The total number of accessible states of N non interacting particles of spin ½ is
(A) 1/N
(B) 1/2N
(C) N
(D) N2
15- The electron in a hydrogen atom with a radius equal to first Bohr radius has a velocity equal to
(A) c/27
(B) c/37
(C) c/137
(D) c/237
16- The ratio of frequencies of the first line of the Lyman series and the first line of Balmer series is:
(A) 5/137
(B) 27/137
(C) 27/5
(D) 4/27
17- What is the wavelength of the photon emitted by a hydrogen atom in transition 2s→1s?
(A) 1036 Å
(B) 2436 Å
(C) 1218 Å
(D) 518 Å
18- Find the number of atoms per unit cell in fcc structure.
(A) 1
(B) 2
(C) 3
(D) 4
19- The Fermi level in alkali metal is about:
(A) 1 eV
(B) 2 eV
(C) 5 eV
(D) 10 eV
20- Find the magnetic susceptibility in the Meisner state of a superconductor in SI units
(A) 0
(B) 1
(C) -1
(D) 2
21- Intrinsic concentration of charge carriers in a semiconductor varies with temperature T
(A) 1/T
(B) T2
(C) T-2
(D) T3/2
ANSWERS:
1-(B), 2-(C), 3-(B), 4-(A), 5-(C), 6-(B), 7-(C), 8-(D), 9-(B), 10-(B), 11-(C), 12-(A), 13-(B), 14-(C), 15-(C), 16-(C), 17-(C), 18-(D), 19-(C), 20-(C), 21-(D)