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_____________?

Related Mcqs:

1. Copper wire of certain length and resistance is drawn out to three times its length without change in volume, the new resistance of wire becomes__________?

   A. 1/9 times
   B. 3 times
   C. 9 times
   D. unchanged

2. When resistance element of a heater fuses and then we reconnect it after removing a portion of it, the power of the heater will___________?

   A. decrease
   B. increase
   C. remain constant
   D. none of the above

3. Nichrome wire is an alloy of_____________?

   A. lead and zinc
   B. chromium and vanadium
   C. nickel and chromium
   D. copper and silver

4. The resistance of a copper wire 200 m long is 21 Q. If its thickness (diameter) is 0.44 mm, its specific resistance is around_______________?

   A. 1.2 x 10~8 Q-m
   B. 1.4 x 10~8 Q-m
   C. 1.6 x 10″”8 Q-m
   D. 1.8 x 10″8 Q-m

5. 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_____________?

   A. 160 ohms
   B. 80 ohms
   C. 20 ohms
   D. 10 ohms

6. 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

7. 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

8. 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

9. The resistance of a conductor of diameter d and length l is R Ω. If the diameter of the conductor is halved and its length is doubled, the resistance will be

   A. R Ω
   B. 2R Ω
   C. 4R Ω
   D. 8R Ω

10. The resistance of a parallel circuit consisting of two branches is 12 ohms. If the resistance of one branch is 18 ohms, what is the resistance of the other ?

    A. 18 Q
    B. 36 Q
    C. 48 Q
    D. 64 Q