Two bulbs of 500 W and 200 W rated at 250 V will have resistance ratio as________?

Related Mcqs:

1. 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

2. 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

3. Three 60 W bulbs are in parallel across the 60 V power line. If one bulb burns open_________________?

   A. there will be heavy current in the main line
   B. rest of the two bulbs will not light
   C. all three bulbs will light
   D. the other two bulbs will light

4. 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

5. Bulbs in street lighting are all connected in_____________?

   A. parallel
   B. series
   C. series-parallel
   D. end-to-end

6. 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_____________?

   A. 80 m
   B. 60 m
   C. 40 m
   D. 20 m

7. 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

8. Four wires of same material, the same cross-sectional area and the same length when connected in parallel give a resistance of 25 Q. If the same four wires are connected is series the effective resistance will be________?

   A. 100 Ω
   B. 200 Ω
   C. 300 Ω
   D. 400 Ω

9. 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

10. 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