In the case of direct current____________?
A. magnitude and direction of current remains constant
B. magnitude and direction of current changes with time
C. magnitude of current changes with time
D. magnitude of current remains constant
It becomes more difficult to remove_________________?
A. any electron from the orbit
B. first electron from the orbit
C. second electron from the orbit
D. third electron from the orbit
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
A current of 16 amperes divides between two branches in parallel of resistances 8 ohms and 12 ohms respectively. The current in each branch is_____________?
A. 6.4 A, 6.9 A
B. 6.4 A, 9.6 A
C. 4.6 A, 6.9 A
D. 4.6 A, 9.6 A
Which of the following has no units?
A. Permeability
B. Moment of a magnet
C. Magnetic susceptibility
D Permittivity
Magnetic susceptibility is the degree to which a material is magnetized by an external magnetic field, hence in the SI system it is dimensionless.
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
A closed switch has a resistance of_____________?
A. zero
B. about 50 ohms
C. about 500 ohms
D. infinity