Worksheet: Electromagnetic Induction in Generators

In this worksheet, we will practice describing electromagnetic induction in devices such as generators and dynamos.

Q1:

The graph shows the potential difference against time for three current sources.

Which source provides rectified alternating current?

  • A(c)
  • B(b)
  • C(a)

Which source provides direct current?

  • A(b)
  • B(a)
  • C(c)

Q2:

The diagram shows four graphs of potential difference against time.

What type of current is produced by these four varying potential differences?

  • AAlternating current
  • BPulsating current
  • CRectified alternating current
  • DDirect current

Which graph shows a varying potential difference with the greatest frequency?

  • A(d)
  • B(a)
  • C(b)
  • D(c)

What is the peak voltage of graph (c)?

Which graph shows the varying potential difference with the lowest frequency?

  • A(a)
  • B(d)
  • C(c)
  • D(b)

What is the peak voltage of graph (d)?

Q3:

The graph shows the potential difference against time for three current sources.

Which two current sources have a potential difference with a magnitude that is always nonnegative?

  • A(b) and (c)
  • B(a) and (b)
  • C(a) and (c)

Which current source has a potential difference that is constant over time?

  • A(a)
  • B(b)
  • C(c)

What is the peak voltage of source (c)?

What is the peak voltage of source (b)?

Which of the current sources shown in the graph is most likely to be produced by a dynamo containing a commutator?

  • A(b)
  • B(a)
  • C(c)

Q4:

Parts (a), (b), (c), and (d) of diagram (A) show a setup for a simple alternating current generator. A single loop of copper wire rotates in a uniform magnetic field provided by two permanent magnets. The four parts of the diagram show the loop in four different positions as it rotates.

Diagram (B) is a graph of the current outputted by this generator over time.

Which position of the loop in diagram (A) does the point 𝑃 in diagram (B) correspond to?

  • A(d)
  • B(b)
  • C(a)
  • D(c)

Which position of the loop in diagram (A) does the point 𝑅 in diagram (B) correspond to?

  • A(c)
  • B(a)
  • C(b)
  • D(d)

Q5:

The diagram shows the setup for a simple alternating current generator. A loop of copper wire spins about an axis in a uniform magnetic field between two permanent magnets.

What components are marked by A in the diagram?

  • ACarbon brushes
  • BPermanent magnets
  • CSplit-ring commutators
  • DSolenoids
  • ESlip rings

What components are marked by B in the diagram?

  • ASplit-ring commutators
  • BPermanent magnets
  • CCarbon brushes
  • DSlip rings
  • EElectrodes

Q6:

Diagram (a) shows a generator consisting of a loop of wire that spins in the uniform magnetic field created between two permanent magnets. Diagram (b) shows a cross section of the generator, showing the direction of the magnetic field and the path of the two sides of the wire loop. Diagram (c) shows the potential difference induced in the wire by this motion against time. Which point on the graph in diagram (c) corresponds to the position of the wire shown in diagram (b)?