Question: The conduction of electricity, in semiconductors, takes place due to movement of______________?

• 1. positive ions only
• 2. negative ions only
• 3. positive and negative ions
• 4. electrons and holes

Question: Thermocouples are mainly used for the measurement of_____________?

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

Question: Which of the following materials is the best conductor of electricity ?

• 1. Tungsten
• 2. Aluminium
• 3. Copper
• 4. Carbon

Question: Due to which of the following reasons copper and aluminium are not used for heating elements ?

• 1. Both have great tendency for oxidation
• 2. Both have low melting point
• 3. Very large length of wires will be required
• 4. All of the above

Question: Which of the following is a semiconductor material ?

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

Question: ___________ has the best damping properties?

• 1. Diamond
• 2. High speed steel
• 3. Mild steel
• 4. Cast iron

Question: Spark plug makes use of which of the following materials for insulation ?

• 1. Porcelain
• 2. Slate
• 3. Asbestos
• 4. Glass

Question: The photo-electric effect occurs only when the incident light has more than a certain critical____________?

• 1. intensity
• 2. speed
• 3. frequency
• 4. wave length

Question: Selenium is __________ semiconductor?

• 1. extrnisic
• 2. intmisic
• 3. N-type
• 4. P-type

Question: Due to which of the following fact, in India, aluminium is replacing copper ?

• 1. Aluminium is more ductile and malleable than copper
• 2. Aluminium is available in plenty, cheaper and lighter than copper
• 3. Aluminium has lower resistivity than that of copper
• 4. Aluminium has less temperature co-efficient than copper