Resistance of a material always decreases if __________?
A. temperature of material is decreased
B. temperature of material is increased
C. number of free electrons available become more
D. none of the above is correct
Author: Aroma Ann
When electric current passes through a metallic conductor, its temperature rises. This is due to __________?
A. collisions between conduction electrons and atoms
B. the release of conduction electrons from parent atoms
C. mutual collisions between metal atoms
D. mutual collisions between conducting electrons
Two bulbs of 500 W and 200 W rated at 250 V will have resistance ratio as __________?
A. 4 : 25
B. 25 : 4
C. 2 : 5
D. 5 : 2
Two resistances Rl and Ri are connected in series across the voltage source where Rl>Ri. The largest drop will be across __________?
A. Rl
B. Ri
C. either Rl or Ri
D. none of them
A 40 W bulb is connected in series with a room heater. If now 40 W bulb is replaced by 100 W bulb, the heater output will __________?
A. decrease
B. increase
C. remain same
D. heater will burn out
If a wire conductor of 0.2 ohm resistance is doubled in length, its resistance becomes __________?
A. 0.4 ohm
B. 0.6 ohm
C. 0.8 ohm
D. 1.0 ohm
The four bulbs of 40 W each are connected in series swift a battery across them, which of the following statement is true?
A. The current through each bulb in same
B. The voltage across each bulb is not same
C. The power dissipation in each bulb is not same
D. None of the above
The resistance of a few meters of wire conductor in closed electrical circuit is __________?
A. practically zero
B. low
C. high
D. very high
In a series circuit with unequal resistances, the __________?
A. the highest resistance has the most of the current through it
B. the lowest resistance has the highest voltage drop
C. the lowest resistance has the highest current
D. the highest resistance has the highest voltage drop
A 3 Q resistor having 2 A current will dissipate the power of __________?
A. 2 watts
B. 4 watts
C. 6 watts
D. 8 watts
