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________?

Related Mcqs:

1. 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

2. Three identical resistors are first connected in parallel and then in series. The resultant resistance of the first combination to the second will be_________________?

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

3. 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

4. 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

5. 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

6. 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

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.  If P is the power of a star connected system then what will be power of an equivalent delta connected system?

   A. P
   B. 3P
   C. P/3
   D. None of the above

   Updated by: muhammad rahim

9. With three resistances connected in parallel, if each dissipates 20 W the total power supplied by the voltage source equals_____________?

   A. 10 W
   B. 20 W
   C. 40 W
   D. 60 W

10. 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