Mercury as an electric contact material is_______________?
A. a liquid
B. a metal
C. a metal liquid
D. a gas
Month: December 2018
On which of the following factors does the resistivity of a material depend ?
On which of the following factors does the resistivity of a material depend ?
A. Resistance of the conductor
B. Area of the conductor section
C. Length of the conductor
D. All of the above
The value of critical field below the transition temperature will_______________?
The value of critical field below the transition temperature will_______________?
A. increase
B. decrease
C. remain unchanged
D. any of the above
Superconductivity is observed for____________?
Superconductivity is observed for____________?
A. infrared frequencies
B. d.c. and low frequency
C. a.c. and high frequency
D. frequencies having no effect
E. none of the above
highest conductivity_____________?
highest conductivity_____________?
B. lowest temperature co-efficient
C. good mechanical strength
D. good corrosion resistance
E. easy solderable and drawable quality
F. all of the above
High resistivity materials are used in_____________?
High resistivity materials are used in_____________?
A. precision instruments
B. heating elements
C. motor starters
D. incandescent lamps
E. all of the above
In a superconductor the value of critical density depends upon______________?
In a superconductor the value of critical density depends upon______________?
A. magnetic field strength
B. temperature
C. either (A) or (B)
D. both (A) and (B)
The conductivity of a conductor can be increased by_______________?
The conductivity of a conductor can be increased by_______________?
A. decreasing its temperature
B. increasing its temperature
C. decreasing its vibration
D. increasing its vibration
The superconductivity is due to____________?
The superconductivity is due to____________?
A. the crystal structure having no atomic vibration at 0°K
B. all electrons interact in the super-conducting state
C. the electrons jump into nucleus at 0°K
D. none of the above
Superconductors are becoming popular for use in________________?
Superconductors are becoming popular for use in________________?
A. generating very strong magnetic field
B. manufacture of bubble memories
C. generating electrostatic field
D. generating regions free from magnetic field