Electric Current and Resistance Fundamentals Quiz

An electric current exists only when electric charges of like signs move.

The SI unit of current is Coulomb (C).

In a common conductor like copper, the current is due to the motion of positively charged electrons.

The average current is defined as the charge passing through an area per unit area.

The drift speed of charge carriers in a conductor is directly proportional to the current density.

A mobile charge carrier in a metal can be either positive or negative.

The resistance of a conductor is directly proportional to its length and inversely proportional to its cross-sectional area.

The potential difference across a conductor with uniform field is related to the field through the relationship J = I/A.

The units of resistance are expressed in ohms (Ω).

The resistance of a material increases as its temperature decreases.

The circuit resistance decreases when resistors R1 and R2 are in parallel and the switch is closed, resulting in an increase in current.

An ammeter measures voltage and should be connected in parallel.

The equivalent capacitance of capacitors connected in parallel is the inverse of the equivalent capacitance of capacitors connected in series.

If the material obeys Ohm’s law, the energy equivalent of one kilowatt-hour can be calculated using the formula E = P*t.

The potential difference across a conductor with a uniform field is related to the field through the relationship J = I/A.

In a series circuit, the potential differences across the resistors add directly to give the equivalent resistance of the series combination.

The equivalent resistance of a series combination of resistors is the algebraic sum of the individual resistances and is always less than any of the individual resistors.

Replacing any resistors in series or in parallel reduces a complicated circuit to a simple circuit with only one resistor.

In a parallel circuit, the inverse of the equivalent resistance of two or more resistors connected in parallel is the algebraic sum of the inverses of the individual resistances, and the equivalent is always greater than the smallest resistor in the group.

When resistors are connected in parallel, the potential difference across each resistor is not the same because each is connected directly across the battery terminals.