Question: Which of the following factors affect resistivity of metals ?

• 1. Age hardening
• 2. Alloying
• 3. Temperature
• 4. All of the above

Question: Superconducting metal in super conducting state has relative permeability of________________?

• 1. zero
• 2. one
• 3. negative
• 4. more than one

Question: For a particular material the Hall coefficient was found to be zero. The material is______________?

• 1. insulator
• 2. metal
• 3. intrinsic semiconductor
• 4. none of the above

Question: For a hole which of the following statements is incorrect ?

• 1. Holes can exist in certain semiconductors only
• 2. Holes can exist in any material including conductors
• 3. Holes may constitute an electric current
• 4. Holes can be considered as a net positive charge

Question: The carbon percentage is least in__________________?

• 1. low carbon steel
• 2. wrought iron
• 3. cast iron
• 4. malleable iron

Question: is an element used in semiconductors whose atoms have three valence electrons?

• 1. An acceptor
• 2. A donor
• 3. Germanium
• 4. Silicon

Question: For germanium the forbidden energy gap is_______________?

• 1. 0.15 eV
• 2. 0.25 eV
• 3. 0.5eV
• 4. 0.7eV

Question: The current due to electron flow in conduction band is the hole current in valence band?

• 1. equal to
• 2. less than
• 3. greater than
• 4. any of the above

Question: The minority carrier concentration is largely a function of_____________?

• 1. forward biasing voltage
• 2. reverse biasing voltage
• 3. temperature
• 4. the amount of doping

Question: is usually used for brush rockers____________?

• 1. Mild steel
• 2. Copper
• 3. Aluminium
• 4. Cast-iron