Physics Electricity

Look at this circuit.

What can you say about the total resistance of this combination of resistors?

• This parallel arrangement has less resistance than either R1 or R2

• This parallel arrangement has a resistance between that of R1 and R2

• This parallel arrangement has more resistance than R1 or R2

• This parallel arrangement has more resistance than R1 and R2 added together

What unit is used to measure voltage (or potential difference)?

• Amps (A)

• Volts (V)

• Coulombs (C)

• Joules (J)

The correct form of Ohm's Law, linking potential difference V, current I and resistance R is…

• V = I × R

• V = I + R

• V = I/R

• V = R/I

How can you describe a.c, or alternating current?

• A current with the same strength and direction all the time

• A current that varies in strength and swaps direction smoothly and regularly

• A current that has the same strength but changes direction regularly

• A current that changes strength regularly but always in the same direction

What is the term used to describe the opposition that a device or material offers to the flow of direct current?

• Resistance

• Capacitance

• Inductance

• Conductance

Which of the following is a correct representation of Ohm's Law?

• All of the above

What is the unit of electrical resistance?

• Volt

• Ampere

• Ohm

• Watt

A current of 0.5 A flows for 2 minutes in a circuit.

The charge flow is…

• 1 C

• 2 C

• 60 C

• 120 C

What does this graph show?

• Resistance and length of wire are proportional

• Resistance and length of wire are directly proportional

• Resistance and length of wire are inversely proportional

• Resistance and length of wire are unrelated

Why is distributing the same power through the National Grid more efficient at a lower current?

• Low voltages are safer

• High currents heat up the cables, wasting energy

• High currents get more electricity through to the consumer

• High voltages are safer