1: Which method can be used to distinguish between the two types of carriers
a. Hall effect
b. Rayleigh method
c. Doppler effect
d. Fermi effect
2: Current is flowing in two long parallel conductors in the same direction. The conductors · · · each other
a. Are inclined to
b. Repel
c. Attract
d. Neither attract nor repel
3: Cathode rays enter in a uniform magnetic field perpendicular to direction of field. In magnetic field their path will be
a. Circle
b. Parabolic
c. Straight line
d. Elliptical
4: The force experienced by a charged particle in magnetic field is maximum when particle move in a direction
a. Perpendicular to
b. Parallel to
c. Is at rest
d. None of these
5: A particle moving in a magnetic field has an increase in its velocity then its radius of circle
a. Becomes half
b. Increases
c. Decreases
d. Remains same
6: If relative permeability of a substance is 0.79, then it is · · · material
a. Diamagnetic
b. Paramagnetic
c. Ferromagnetic
d. None of these
7: An electron enters a magnetic field acting vertically downward with a velocity v from east. The electron is deflected along
a. South
b. North
c. Southeast
d. Northeast
8: A charged particle moves through a magnetic field in a direction perpendicular to it. Then · · · remains unchanged
a. Direction
b. Speed
c. Velocity
d. Acceleration
9: Magnetic dipole moment is defined as
a. $\mu =\frac{I}{A}$
b. $\mu =\frac{A}{I}$
c. µ = IA
d. None of these
10: Which define the relation between magnetic torque and magnetic dipole moment
a. $\vec{\tau}\ =\vec{\mu}\ \times\ \vec{B}$
b. $\vec{\tau}=\vec{\mu} . B$
c. $\vec{\tau}\ =\ -\vec{\mu}\ .\vec{B}$
d. None of these
11: Resistivity (Ohm – m) of semiconductor varies
a. $\mathbf{{10}^{-5}\ -\ {10}^4}$
b. ${10}^{-6}\ -\ {10}^3$
c. ${10}^{-4}\ -\ {10}^5$
d. ${10}^5\ -\ {10}^{-5}$
12: Semiconductor compound is
a. Germanium
b. Sodium Chloride
c. Gallium Arsenide
d. Sodium Phosphate
13: Orbital of valance conducting band overlap in
a. Metals
b. Semiconductors
c. Conductors
d. Semi-metals
14: At 0K the valance band in intrinsic semiconductor is
a. Completely filled
b. Complete empty
c. Partially filled
d. Almost filled
15: In intrinsic semiconductor rate of generation of carrier’s ‘g” depends on
a. Volume
b. Temperature
c. Pressure
d. Entropy
16: Popping ratio is
a. ${10}^4\ -\ {10}^8$
b. $\mathbf{{10}^6\ -\ {10}^8}$
c. ${10}^7\ -\ {10}^9$
d. ${10}^3\ -\ {10}^6$
17: N-type semiconductors are made by adding
a. Group III
b. Group VI
c. Period III
d. Period VI
18: Both n and p type doping are charged
a. Neutral
b. Positive
c. Negative
d. Region dependent
19: With increasing depth in valance band the hole probability. . ..
a. Increases exponentially
b. Decreases exponentially
c. Increases linearly
d. Decreases linearly
20: Current density and drift velocity depends on
a. External electric field
b. External magnetic field
c. Both
d. Independent
21: The strongest diamagnetic material is
a. Bismuth
b. Hydrogen
c. Helium
d. Neon
22: The temperature at which ferromagnetic material changes into paramagnetic material is known as
a. Critical temp
b. Temp. inversion
c. Debye temp
d. Curie’s temp.
23: Which of the following magnetic substance can have positive permeability and negative susceptibility
a. Ferromagnetic
b. Paramagnetic
c. Diamagnetic
d. None
24: The susceptibility of diamagnetic material is
a. Very large
b. Small but positive
c. Small but negative
d. Zero
25: Paramagnetic susceptibility varies as
a. T
b. $T^2$
c. $T^{-2}$
d. $\mathbf{T^{-1}}$
26: Curie-Weiss law is
a. $\chi_m\ =\frac{C}{T}$
b. $\chi_m\ =\frac{C}{\theta}$
c. $\mathbf{\chi_m\ =\frac{C}{T-\theta}}$
d. $\chi_m\ =\frac{T-\theta}{C}$
27: Which of the following is diamagnetic
a. Water
b. Air
c. Copper sulphate
d. Liquid oxygen
28: The relation between magnetic susceptibility and relative permeability is
a. $\chi\ =\ 1\ -\ \mu_r$
b. $\chi\ =\ 1\ +\ \mu_r$
c. $\mu_r=\ 1\ -\ \chi$
d. $\mathbf{\mu_r==\ 1\ +\ \chi}$
29: The relative permeability of air is
a. 1
b. 1.3
c. 0.5
d. 2
30: The most suitable material for making permanent magnet is
a. Nickel
b. Copper
c. Steel
d. Soft iron
31: Superconductivity was first discovered by
a. Meissner and Schoenfeld
b. C.H. Townes
c. H. Kamerlingh Onnes
d. C.A. Reynolds
32: The metal mercury becomes superconductor at
a. $\mathbf{4.15\ K }$
b. $4.15\ \ \deg c$
c. $4.15\ ^of$
d. $4.15\ R$
33: A superconductor has
a. Zero conductivity
b. Infinite resistivity
c. Infinite conductivity
d. None
34: Magnetic susceptibility of superconductors is given by
a. $\mathbf{\chi\ =\ -1 }$
b. $\chi\ =\ 0$
c. $\ \chi\ =\ 1$
d. $\ \chi\ >>\ 1$
35: The temperature at which a metal becomes super-conducting is called
a. Neel temp
b. Curie’s temp
c. Meissner point
d. Transition temp
36: Superconductivity is usually exhibited at temperatures
a. Low
b. High
c. Very high
d. None of these
37: Which of the property is not exhibited by superconductors
a. µr = 0
b. Copper loss = 0
c. $\mathbf{B\neq\ 0 }$
d. $\chi\ =\ -1$
38: According to isotope effect, the transition temperature Tc for superconductor is proportional to
a. $\mathbf{M^{-\frac{1}{2}}}$
b. $M^{-\frac{1}{4}}$
c. $\sqrt M$
d. $-\frac{1}{M}$
39: BCS theory is an attempt to explain
a. Magnetism
b. Superconductivity
c. Thermoelectric effect
d. Heating effect
40: In a particular superconductor, transition takes place gradually, it belongs to
a. Type-I
b. Type-II
c. Type-I and Type-II both
d. None of these
