Question: Which method can be used for absolute measurement of resistances _______________?

• 1. Lorentz method
• 2. Releigh method
• 3. Ohm’s law method
• 4. Wheatstone bridge method

Question: Ohm’s law is not applicable to__________?

• 1. semi-conductors
• 2. DC circuits
• 3. small resistors
• 4. high currents

Question: Two copper conductors have equal length. The cross-sectional area of one conductor is four times that of the other. If the conductor having smaller cross-sectional area has a resistance of 40 ohms the resistance of other conductor will be_____________?

• 1. 160 ohms
• 2. 80 ohms
• 3. 20 ohms
• 4. 10 ohms

Question: A nichrome wire used as a heater coil has the resistance of 2 £2/m. For a heater of 1 kW at 200 V, the length of wire required will be_____________?

• 1. 80 m
• 2. 60 m
• 3. 40 m
• 4. 20 m

Question: Temperature co-efficient of resistance is expressed in terms of___________?

• 1. ohms/°C
• 2. mhos/ohm°C
• 3. ohms/ohm°C
• 4. mhos/°C

Question: When current flows through heater coil it glows but supply wiring does not glow because______________?

• 1. current through supply line flows at slower speed
• 2. supply wiring is covered with insulation layer
• 3. resistance of heater coil is more than the supply wires
• 4. supply wires are made of superior material

Question: The condition for the validity under Ohm’s law is that_______________?

• 1. resistance must be uniform
• 2. current should be proportional to the size of the resistance
• 3. resistance must be wire wound type
• 4. temperature at positive end should be more than the temperature at negative end

Question: Which of the following statement is correct_______________?

• 1. A semi-conductor is a material whose conductivity is same as between that of a conductor and an insulator
• 2. A semi-conductor is a material which has conductivity having average value of conductivity of metal and insulator
• 3. A semi-conductor is one which con¬ducts only half of the applied voltage
• 4. A semi-conductor is a material made of alternate layers of conducting material and insulator

Question: A rheostat differs from potentiometer in the respect that it_____________?

• 1. has lower wattage rating
• 2. has higher wattage rating
• 3. has large number of turns
• 4. offers large number of tapping

Question: An open resistor, when checked with an ohm-meter reads_____________?

• 1. zero
• 2. infinite
• 3. high but within tolerance
• 4. low but not zero