Q .
In atomic physics, a state with l = 0 is called p state.
A. True
B. False
C.
D.
E. NA
Click Button to See Correct Answer.
Q . Assertion (A): Electronic and Ionic polarization in a polyatomic gas are independent of temperature.
Reason (R): The orientation polarization is independent of temperature.
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA
Click Button to See Correct Answer.
Q .
The core of a coil has a length of 10 cm. The self inductance is 8 mH. If the core length is doubled, all other quantities remaining the same, the self inductance will be
A. 32 mH
B. 16 mH
C. 8 mH
D. 4 mH
E. NA
Click Button to See Correct Answer.
Q .
In paramagnetic materials
A. permanent magnetic dipoles exist but the interaction between neighbouring dipoles is negligible
B. permanent magnetic dipole do not exist
C. permanent magnetic dipoles exist and the interaction between neighbouring dipoles is very strong
D. permanent magnetic dipole moment may or may not exist
E. NA
Click Button to See Correct Answer.
Q .
If the temperature of an extrinsic semiconductor is increased so that the intrinsic carrier concentration is doubled, then
A. the majority carrier density is doubled
B. the minority carrier density is doubled
C. the minority carrier density becomes 4 times the original value
D. both the majority and minority carrier densities double
E. NA
Click Button to See Correct Answer.
Q . Assertion (A): For Diamond, μr = 1
Reason (R): Diamond is a diamagnetic material.
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA
Click Button to See Correct Answer.
Q .
If n denotes principal quantum number, the angular quantum number l = 0, 1... (n - 1).
A. True
B. False
C.
D.
E. NA
Click Button to See Correct Answer.
Q .
Diamond is a paramagnetic material.
A. True
B. False
C.
D.
E. NA
Click Button to See Correct Answer.
Q .
The attraction between the nucleus and valence electron of copper atom is
A. zero
B. weak
C. strong
D. either zero or strong
E. NA
Click Button to See Correct Answer.
Q . Assertion (A): Silicon is less sensitive to changes in temperature than germanium.
Reason (R): Cut in voltage in silicon is less than that in germanium.
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA
Click Button to See Correct Answer.
Q .
If e is the charge of an electron, R is the radius of its orbit and ω is the angular velocity of electron, the magnetic dipole moment μm of the orbit is |μm| = eωR2.
A. True
B. False
C.
D.
E. NA
Click Button to See Correct Answer.
Q . Assertion (A): Magnetic susceptibility of diamagnetic materials is much less than that of paramagnetic materials.
Reason (R): For diamagnetic as well as paramagnetic materials, μr is nearly equal to 1.
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA
Click Button to See Correct Answer.
Q . Assertion (A): In a perfect capacitor, the current density is given by ω ∈0E0∈'rcos(ωt + 90°), where ∈r' is real part of dielectric constant.
Reason (R): In a perfect capacitor, dielectric losses are zero.
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA
Click Button to See Correct Answer.
Q .
The minority carrier life time and diffusion constant in a semiconducting material are 100 μs and 100 cm2/s respectively. The diffusion length of carriers is
A. 0.1 cm
B. 0.01 cm
C. 0.0141 cm
D. 1 cm
E. NA
Click Button to See Correct Answer.
Q .
The apparent capacitance at a high angular frequency ω of an air cored capacitor having capacitance C and inductance L is given by
A.
B.
C.
D.
E. NA
Click Button to See Correct Answer.
Q .
In metals the valence electron wave functions are strongly perturbed by the presence of neighbouring atoms.
A. True
B. False
C.
D.
E. NA
Click Button to See Correct Answer.
Q .
The number of valence electrons in donor impurity are
A. 5
B. 4
C. 3
D. 1
E. NA
Click Button to See Correct Answer.
Q .
Two materials having temperature coefficients of 0.004 and 0.0004 respectively are joined in series. The overall temperature coefficient is likely to be
A. 0.08
B. 0.04
C. 0.001
D. 0.0001
E. NA
Click Button to See Correct Answer.
Q .
If a piece of wood is placed in a magnetic field
A. the magnetic field will not be affected
B. the magnetic lines of force will bend towards the piece
C. the magnetic lines of force will bend away from the piece
D. the flux may increase or decrease
E. NA
Click Button to See Correct Answer.
Q .
The conductivity of intrinsic semiconductor is given by
A. eni(μp - μn)
B. eni(μp + μn)
C. ni(μp + μn)
D. ni(μpμn)
E. NA
Click Button to See Correct Answer.
Q .
Ferroelectric materials are those which
A. cannot be polarized
B. have a permanent polarization
C. have a e equal to zero
D. have μp = 0
E. NA
Click Button to See Correct Answer.
Q . Assertion (A): Power loss in a conductor of resistance P = I2R.
Reason (R): When a conductor is carrying current with current density J as a result of applied field E, then heat developed/m3/ second = JE.
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA
Click Button to See Correct Answer.
Q .
Material which lack permanent magnetic dipoles are known as
A. paramagnetic
B. diamagnetic
C. ferromagnetic
D. ferrimagnetic
E. NA
Click Button to See Correct Answer.
Q .
At room temperature, the current in intrinsic semiconductor is due to
A. holes
B. electrons
C. ions
D. holes and electrons
E. NA
Q .
For a paramagnetic material, susceptiblity increases with increasing temperature.
A. True
B. False
C.
D.
E. NA
Click Button to See Correct Answer.
Q .
Which element exhibits the property of inertia?
A. Resistance
B. Capacitance
C. Inductance
D. Both resistance and inductance
E. NA
Click Button to See Correct Answer.
Q .
The number of valence electrons in pentavalent impurity is
A. 5
B. 4
C. 3
D. 1
E. NA
Click Button to See Correct Answer.
Q . Assertion (A): Ferroelectric materials have spontaneous polarization.
Reason (R): Above curie temperature, ∈ = for ferro-electric materials.
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA
Click Button to See Correct Answer.
Q .
The hysteresis phenomenon in ferromagnetic materials exists at all temperatures.
A. True
B. False
C.
D.
E. NA
Click Button to See Correct Answer.
Q .
In a coaxial cable, braided copper is used for
A. conductor
B. shield
C. dielectric
D. jacket
E. NA
Click Button to See Correct Answer.
Q .
Hydrogen is used in
A. large size transformers
B. MCB
C. large size generators
D. circuit breakers
E. NA
Click Button to See Correct Answer.
Q .
The units of μ0 and μr are
A. H/m for both
B. H/m for μr and no units for μ0
C. H/m for μ0 and no units for μr
D. Wb/m for μ0 and no units for μr
E. NA
Click Button to See Correct Answer.
Q . Assertion (A): In imperfect capacitors, the current does not lead the applied ac voltage by 90°.
Reason (R): When subjected to ac fields, the dielectric constant can be expressed as ∈'r - j∈"r.
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA
Click Button to See Correct Answer.
Q .
Which of the following are donor impurities? GoldPhosphorusBoronAntimonyArsenicInduim Select the correct answer using the following codes
A. 1, 2, 3
B. 1, 2, 4, 6
C. 3, 4, 5, 6
D. 2, 4, 5
E. NA
Click Button to See Correct Answer.
Q .
In a true valence crystal, the bonding between the atoms is accomplished by the sharing of valence electrons.
A. True
B. False
C.
D.
E. NA
Click Button to See Correct Answer.
Q .
If the diameter of a wire is doubled, its current carrying capacity becomes
A. one-fourth
B. half
C. twice
D. four times
E. NA
Click Button to See Correct Answer.
Q .
Which capacitor-store higher amount of energy?
A. Air capacitor
B. Paper capacitor
C. Mica capacitor
D. Plastic film capacitor
E. NA
Click Button to See Correct Answer.
Q .
A parallel plate capacitor has its length, width and separation doubled. It fringing effects are neglected, to keep the capacitance same, the dielectric constant must be
A. halved
B. kept the same
C. doubled
D. made 4 times
E. NA
Click Button to See Correct Answer.
Q . Assertion (A): If E is available energy state eV and EF is Fermi level, then probability of energy state E being occupied = 0.5.
Reason (R): .
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA
Click Button to See Correct Answer.
Q .
For a permanent magnetic material
A. the residual induction and coercive field should be large
B. the residual induction and coercive field should be small
C. area of hysteresis loop should be small
D. initial relative permeability should be high
E. NA
Click Button to See Correct Answer.
Q .
When an electric field E is applied to solid and liquid insulating materials, the internal field Ei acting at the location of atom is such that
A. Ei = E
B. Ei > E
C. Ei < E
D. Ei may be equal to or less than E
E. NA
Click Button to See Correct Answer.
Q . Assertion (A): For a solenoid having N turns, .
Reason (R): For all magnetic materials, B increases linearly with I.
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA
Click Button to See Correct Answer.
Q . Assertion (A): Atomic number of sodium is 11.
Reason (R): Sodium has a body centred cubic lattice.
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA
Click Button to See Correct Answer.
Q .
There is no hysteresis phenomenon is any dielectric material.
A. True
B. False
C.
D.
E. NA
Click Button to See Correct Answer.
Q .
If a sample of germanium and a sample of silicon have the same impurity density and are kept at room temperature
A. both will have equal value of resistivity
B. both will have equal negative resistivity
C. resistivity of germanium will be higher than that of silicon
D. resistivity of silicon will be higher than that of germanium
E. NA
Click Button to See Correct Answer.
Q . Assertion (A): At a temperature of 1000 K, thermionic emission current is about 0.1 A/cm2 of surface.
Reason (R): Thermionic emission current is given by Ith = SA0 T2 e-Ew/kT.
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA