Q. 01 As per Indian Standards of insulating materials, electrical machinery and apparatus in relation to their thermal stability are classified as:
A. Class Y, Class A
B. Class E, Class B
C. Class F, Class H, Class C
D. all of the above
Ans.: D
Q. 02 Which of the following class of insulating materials can withstand temperature up 90ºC and 105ºC?
A. Class E, Class B
B. Class Y, Class A
C. Class F, Class H
D. Class C
Ans.: B
Q. 3 Insulating materials of Class F and H are used up to temperature range___.
A. up to 90ºC and up to 105ºC
B. up to 120ºC and up to 130ºC
C. up to 105ºC and up to 120ºC
D. up to 155ºC and up to 180ºC
Ans.: D
Q. 4 Which of the following class of insulating materials can withstand temperature up 120ºC and 130ºC?
A. Class E, Class B
B. Class Y, Class A
C. Class F, Class H
D. Class C
Ans.: A
Q. 5 Which of the following class of insulating materials used beyond or above 180ºC?
A. Class B
B. Class A
C. Class H
D. Class C
Ans.: C
Q. 6 _____ materials are non linear dielectrics and have high dielectric constant.
A. Ferromagnetic
B. Diamagnetic
C. Dielectric
D. none of the above
Ans.: A
Q. 7 Ferroelectric materials exhibit____.
A. Non linear polarization
B. hysteresis loop
C. Both A and B
D. None of the above
Ans.: C
Q. 8 If the centre of gravity of the positive and negative charges in a body do not coincide in the absence of an applied electric field, the substance has an electric dipole moment and it is said to be spontaneous polarized. This type of substance is known as_____.
A. dielectrics
D. Semiconductors
C. ferroelectric
D. all of the above
Ans.: C
Q. 9 When the temperature exceeds a certain value called _____. The substance loses its ferroelectric properties.
A. saturated point
B. Curie point
C. Under saturation
D. none of the above
Ans.: B
Q. 10 Which of the following is/ are ferroelectric materials?
A. Rochelle salt
B. potassium dihydrogen phosphate and its isomorphous salts
C. Barium titanate
D. All of the above
Ans.: D
Q. 11 Magnetic materials strengthen the magnetic filed in which they placed and posses_____.
A. low permeability
B. high permeability
C. high permittivity
D. low permittivity
Ans.: B
Q. 12 ______ materials are suitable for use as magnetic screens, magnetic cores and circuit and permanent magnets.
A. Magnetic materials
B. Insulating materials
C. Conducting materials
D. none of the above
Ans.: A
Q. 13 Magnetic materials cane classified as:
A. diamagnetic materials
B. paramagnetic materials
C. ferromagnetic materials, ferrites
D. all of the above
Ans.: D
Q. 14 ____ materials which do not strongly attracted by magnet.
A. Ferromagnetic
B. Paramagnetic
C. Diamagnetic
D. ferrites
Ans.: B
Q. 15 Example of paramagnetic material is/ are__.
A. Aluminium
B. Platinum
C. Magnesium
D. All of the above
Ans.: D