Practice Questions
Electricity
Kirchhoff’s law
Q.1 Which combination of units could be used for expressing the power dissipated in a resistor?
A. Newton per second (N s-1 )
B. newton second (N s)
C. newton metre (N m)
D. newton metre per second (N m s-1 )
Q.2 A charged oil drop is held stationary between two charged parallel plates. Which forces act on the oil drop?
A. both electric and gravitational
B. electric only
C. gravitational only
D. neither electric nor gravitational
Q.3 What is the electric field strength in a region where a proton accelerates at 2.00 m s-2 due to the field?
A. 11.4 pV m-1
B. 5.22 nV m-1
C. 10.4 nV m-1
D. 20.9 nV m-1
Q.4 A length of wire is connected into an electric circuit. The current in the wire is measured. Which change on its own could increase the current in the wire?
A. an increase in the length of the wire
B. an increase in the radius of the wire
C. an increase in the resistance of the wire
D. an increase in the resistivity of the wire
Q.5 A cell is described as having an electromotive force (e.m.f.) of 6V. What does this mean?
A. 1 coulomb of charge always dissipates 6 J of energy in the internal resistance of the cell.
B. 1 electron gains 6 J of energy when passing through the cell.
C. There is a potential difference of 6V applied across any external circuit connected to the cell.
D. When 1 coulomb of charge passes through the cell, 6 J of chemical energy is transformed.