An electric filament bulb can be worked from____________?

With rise in temperature the resistance of semi-conductors_________________?

A. decreases
B. increases
C. first increases and then decreases
D. remains constant

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

A. current through supply line flows at slower speed
B. supply wiring is covered with insulation layer
C. resistance of heater coil is more than the supply wires
D. supply wires are made of superior material

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

A. resistance must be uniform
B. current should be proportional to the size of the resistance
C. resistance must be wire wound type
D. temperature at positive end should be more than the temperature at negative end

In the case of direct current____________?

A. magnitude and direction of current remains constant
B. magnitude and direction of current changes with time
C. magnitude of current changes with time
D. magnitude of current remains constant

The hot resistance of the bulb’s filament is higher than its cold resistance because the temperature co-efficient of the filament is___________________?

A. zero
B. negative
C. positive
D. about 2 ohms per degree