Electrical Engineering Materials

81. The transition temperature of mercury is

1. 18.0°K
2. 9.22°K
3. 4.12°K
4. 1.14’K

View answer

82. The value of critical field below the transition temperature will

1. increase
2. decrease
3. remain unchanged
4. any of the above

View answer

83. Thermocouples are mainly used for the measurement of

1. temperature
2. resistance
3. eddy currents
4. coupling co-efficient

View answer

84. Thermonic emission occurs in

1. vacuum tubes
2. copper conductors
3. ferrite cores
4. transistors

View answer

85. Total number of crystal systems is

1. 2
2. 4
3. 7
4. 12

View answer

86. Which of the following affect greatly the resistivity of electrical conductors?

1. Composition
2. Pressure
3. Size
4. Temperature

View answer

87. Which of the following are non-conductors of electricity?

1. Non-metal solids except carbon
2. Air and most other gases
3. Pure water and liquids in general except mercury
4. All of the above

View answer

88. Which of the following factors affect resistivity of metals?

1. Age hardening
2. Alloying
3. Temperature
4. Cold work
5. All of the above

View answer

89. Which of the following high resistance materials has the highest operating temperature?

1. Kanthal
2. Manganin
3. Nichrome
4. Eureka

View answer

90. Which of the following is a semiconductor material?

1. Phosphorous
2. Rubber
3. Silicon
4. Aluminium

View answer