Superconducting metal in super conducting state has relative permeability of________________?
A. zero
B. one
C. negative
D. more than one
Month: December 2018
Which of the following factors affect resistivity of metals ?
Which of the following factors affect resistivity of metals ?
A. Age hardening
B. Alloying
C. Temperature
D. Cold work
E. All of the above
Surface resistance of an insulating material is reduced due to the______________?
Surface resistance of an insulating material is reduced due to the______________?
A. smoky and dirty atmosphere
B. humidity in the atmosphere
C. both (A) and (b)
D. neither (A) nor (b)
In conductors conduction of electricity takes place due to movement of_______________?
In conductors conduction of electricity takes place due to movement of_______________?
A. electrons only
B. positive ions only
C. negative ions only
D. positive and negative ions
E. none of the above
Effect of moisture on the insulating materials is to________________?
Effect of moisture on the insulating materials is to________________?
A. decrease dielectric constant
B. decrease dielectric strength
C. decrease insulation resistance
D. increase dielectric loss
E. all of the above
The forbidden gap in an insulator is________________?
The forbidden gap in an insulator is________________?
A. large
B. small
C. nil
D. any of the above
If the resistance of a conductor does not vary in accordance with Ohm’s law it is known as____________?
If the resistance of a conductor does not vary in accordance with Ohm’s law it is known as____________?
A. non-linear conductor
B. reverse conductor
C. bad-conductor
D. non-conductor
Due to which of the following fact, in India, aluminium is replacing copper ?
Due to which of the following fact, in India, aluminium is replacing copper ?
A. Aluminium is more ductile and malleable than copper
B. Aluminium is available in plenty, cheaper and lighter than copper
C. Aluminium has lower resistivity than that of copper
D. Aluminium has less temperature co-efficient than copper
Selenium is __________ semiconductor?
Selenium is __________ semiconductor?
A. extrnisic
B. intmisic
C. N-type
D. P-type
The photo-electric effect occurs only when the incident light has more than a certain critical____________?
The photo-electric effect occurs only when the incident light has more than a certain critical____________?
A. intensity
B. speed
C. frequency
D. wave length