Related Questions

The transition temperature at which all the ferromagnetic materials become paramagnetic materials is termed as the 'Curie temperature'. Its value for cobalt is __________ °C.
A 768
B 1127
C 1359
D 1480
__________ is the hardest oxide and is hence used where high wear resistance at high temperature is required.
A Beryllia
B Zirconia
C Alumina
D Magnesia
Which of the following resistive materials has the lowest temperature co-efficient of resistance ?
A Nichrome
B Constantan
C Kanthal
D Molybdenum
Which of the following materials has a negative temperature coefficient of resistance?
A Copper
B Aluminum
C Carbon
D Brass
Which of the following insulating materials can withstand the highest temperature safely?
A Cellulose
B Asbestos
C Mica
D Glass fibre
The device which transfer the signal from low resistance region to high resistance region is
A Diode
B Transistor
C Capacitor
D Inductor
The hot resistance of the bulb's filament is higher than its cold resistance because the temperature coefficient of the filament is
A Zero
B Negative
C Positive
D About 2 ohms per degree
Resistance variation method of temperature control is done by connecting resistance elements in
A Series
B Parallel
C Series-parallel connections
D All of the above ways
A high vapour velocity is required for high plate efficiency in a seive plate coloumn. The satisfactory value of operating vapor velocity for design purpose in seive plate column is about __________ percent of the flooding velocity.
A 45
B 60
C 80
D 95
In resistance heating highest working temperature is obtained from heating elements made of
A Nickel copper
B Nichrome
C Silicon carbide
D Silver

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