In a lamp load when more than one lamp are switched on the total resistance of the load_____________?

Related Mcqs:

1. 74. Sparking occurs when a load is switched off because the circuit has high_________?

   A. resistance
   B. inductance
   C. capacitance
   D. impedance

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. For testing appliances, the wattage of test lamp should be_____________?

   A. very low
   B. low
   C. high
   D. any value

4. Switching of a lamp in house produces noise in the radio. This is because switching operation produces________?

   A. arcs across separating contacts
   B. mechanical noise of high intensity
   C. both mechanical noise and arc between contacts
   D. none of the above

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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