21- The density of states for a metal depends primarily on:
A. The temperature
B. The energy
C. The density of the metal
D. The volume of the sample
View Answer
Answer : B. The energy
Description
22- For an electronic state s = 1 and l = 1 \ the number of possible values of total angular momentum of an electron are:
A. 1
B. 2
C. 3
D. 4
View Answer
Answer : C. 3
Description
23- A positive charge moving with a constant velocity v enters a region of a uniform magnetic field pointing out of the page. What is the direction of the magnetic force on the charge?
A. Left
B. Right
C. To the bottom of the page
D. To the top of the page
View Answer
Answer : C. To the bottom of the page
Description
24- Which of the following is the correct relation between current density and magnetization?
A. I = Grad of M
B. J = Div of M
C. J = Curl of M
D. M = Curl of J
View Answer
Answer : C. J = Curl of M
Description
25- The atomic diameter of a BCC crystal (if a is the lattice parameter) is:
A. a
B. a/2
C. (√3/2)·a
D. (√2)·a
View Answer
Answer : C. (√3/2)·a
Description
26- Data are stored in a random-access memory (RAM) during the:
A. Write operation
B. Enable operation
C. Read operation
D. Addressing operation
View Answer
Answer : A. Write operation
Description
27- Over-damping results in:
A. Slower return to equilibrium
B. Faster return to equilibrium
C. Equilibrium is never achieved
D. Magnitude return to equilibrium
View Answer
Answer : A. Slower return to equilibrium
Description
28- During one oscillation, the phase of oscillation changes by:
A. π radians
B. 2π radians
C. 180 degrees
D. 4π radians
View Answer
Answer : B. 2π radians
Description
29- A radio transmission from an astronaut on the moon will be received how much later on the Earth (the moon is 380 million meters from the Earth)?
A. 0.12 s
B. 0.25 s
C. 0.38 s
D. 1.27 s
View Answer
Answer : D. 1.27 s
Description
30- A sphere, a cube, and a thin circular plate, all made of the same material and having the same mass, are initially heated to a temperature of 3000 K. Which of these will cool the fastest?
A. Sphere
B. Cube
C. Plate
D. None of these
View Answer
Answer : C. Plate
Description
31- Phase difference between a node and an antinode is:
A. 60°
B. 45°
C. 280°
D. None of these
View Answer
Answer : D. None of these
Description
32- The structure of NaCl is:
A. Face-centered cubic system
B. Body-centered cubic system
C. Hexagonal crystal system
D. Triclinic crystal system
View Answer
Answer : A. Face-centered cubic system
Description
33- The total capacitance of a 300 mF capacitor and a 600 mF capacitor in series is:
A. 300 mF
B. 500 mF
C. 200 mF
D. 1000 mF
View Answer
Answer : C. 200 mF
Description
34- Relativistic mechanics produces results different from classical mechanics for bodies moving with:
A. Very high velocities
B. Moderate velocities
C. Low velocities
D. Zero velocity
View Answer
Answer : A. Very high velocities
Description
35- The material which is slightly attracted to a magnetic field is:
A. Diamagnetic
B. Paramagnetic
C. Ferromagnetic
D. None of these
View Answer
Answer : B. Paramagnetic
Description
36- Force exerted on a person by the atmosphere is:
A. 100,000 N
B. 300,000 N
C. 400,000 N
D. 500,000 N
View Answer
Answer : A. 100,000 N
Description
37- Which one of the following constants is not related to radiation?
A. Stefan’s constant
B. Solar constant
C. Bohrmann’s constant
D. Wien’s constant
View Answer
Answer : C. Bohrmann's constant
Description
38- Ferromagnetic materials are obtained from:
A. Copper
B. Zinc
C. Aluminium
D. None of these
View Answer
Answer : D. None of these
Description
39- The dependence of the mobility of charge carriers in a semiconductor is given by:
A. μ ∝ T
B. μ ∝ 1/T
C. μ ∝ T²
D. μ = constant
View Answer
Answer : B. μ ∝ 1/T
Description
40- Refractive index of materials is approximately equal to the square root of:
A. Electrical permittivity
B. Magnetic permeability
C. Electrical permittivity × magnetic permeability
