Materials and Components problems
- 1. Assertion (A): If an electron having charge e is revolving in an orbit of radius R and with angular velocity ?, the magnetic dipole moment of orbit is 0.5 e?R2.
Reason (R): Orbital angular momentum and magnetic dipole moment are always equal.
Options- 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 Discuss
Correct Answer: A is true but R is false
Explanation:
Orbital angular momentum and magnetic dipole moment are not equal.
- 2. For making a capacitor it is better to have a dielectric having
Options- A. high permittivity
- B. low permittivity
- C. permittivity same as that of air
- D. permittivity which is neither high nor low Discuss
Correct Answer: high permittivity
Explanation:
Capacitance is directly proportional to permittivity.
- 3. Assertion (A): The angular momentum of an atom is due to three contributions viz. orbital, electron spin and nuclear spin.
Reason (R): The nuclear spin magnetic moment is much more than electron spin magnetic moment.
Options- 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 Discuss
Correct Answer: A is true but R is false
Explanation:
Nuclear spin is of the same order as electron sum.
- 4. In solid insulator materials having only one kind of atom, the types of polarization which exist are
Options- A. electronic only
- B. electronic and ionic
- C. electronic, ionic and permanent
- D. electronic and permanent Discuss
Correct Answer: electronic only
Explanation:
In elemental dielectrics only electronic polarization exists.
- 5. Schrodinger wave equation is a
Options- A. linear equation
- B. differential equation
- C. partial differential equation
- D. none of the above Discuss
Correct Answer: partial differential equation
- 6. Above a certain temperature, the specific heat of a metal becomes constant. This temperature is called
Options- A. Debye temperature
- B. Curie temperature
- C. Neel temperature
- D. Transition temperature Discuss
Correct Answer: Debye temperature
- 7. For magnetic shielding, we need a ferromagnetic material.
Options- A. True
- B. False Discuss
Correct Answer: True
- 8. At room temperature the number of conducting electrons in an intrinsic semiconductor
Options- A. is almost equal to the number of valence electrons
- B. is about half the number of valence electrons
- C. is small as compared to the number of valence electrons
- D. is a very small fraction of the number of valence electrons Discuss
Correct Answer: is a very small fraction of the number of valence electrons
- 9. As the viscosity of a liquid increases, the relaxation time
Options- A. remains constant
- B. increases
- C. decreases
- D. first decreases then increases Discuss
Correct Answer: increases
Explanation:
Relaxation time increases with viscosity.
- 10. If Bmax is the maximum flux density, eddy current loss is proportional to
Options- A. Bmax
- B. B1.6max
- C. B2max
- D. B3max Discuss
Correct Answer: Bmax
More in Electronics and Communication Engineering:
Programming
Copyright ©CuriousTab. All rights reserved.