A. decreases
B. increases
C. first increases and then decreases
D. remains constant
Related Mcqs:
- 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 - With rise in temperature the resistance of pure metals______________?
A. increases
B. decreases
C. first increases and then decreases
D. remains constant - 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 - 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 - 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 - 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 - 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 - 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 - 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 - Which of the following materials has a negative temperature co-efficient of resistance?
A. Copper
B. Aluminum
C. Carbon
D. Brass
