13Motion of a charged particle in the magnetic field
13Motion of a charged particle in the magnetic field.docx
Theme of the lesson
force. Motion of a charged particle in the magnetic field
Learning objectives that are achieved at
this lesson (Subject Programme reference)
investigate the effect of a magnetic field on moving charged particles;
By the end of this lesson, students will be able to:
magnetic flux density of the magnetic field;
the centripetal force provided by the magnetic field;
speed of thecharged
and analyse qualitatively the deflection of beams of charged particles by
uniform electric and uniform magnetic fields;
the effects of magnetic fields on moving charges;
how electric and magnetic fields can be used in velocity selection;
the main principles of one method for the determination of and
e/me for electrons;
Calculate the the magnetic
flux density of the magnetic field;
Calculate the centripetal force provided by the
Calculate the speed of thecharged
Describe and analyse qualitatively the deflection of
beams of charged particles by uniform electric and uniform magnetic fields;
Describe the effects of magnetic fields on moving
Explain how electric and magnetic fields can be used
in velocity selection;
Explain the main principles of one method for the
determination of and e/me
Subject-specific vocabulary & terminology
magnetic force on a moving charge
a beam of electrons
Fleming’s left-hand rule
deflected up the page
deflected down the page
into the page
out of page
the magnetic flux density B (strength of the
the charge Q on the particle
the speed v of the particle
Useful set(s) of phrases for dialogue/writing
A charged particle entering at right angles to a uniform
magnetic field describes a circular path because the magnetic force is
Differentiated poster-session ,
Collaborative Learning, Progressive Task with Digital resources
at the lesson
Safety, Consideration to others, Co-operation,
Opportunity for Life-Long Learning, Academic Integrity and Transparency,
Respect for Self and Others
Research skills, use of video as introduction
8: magnetic fields; representation of fields by field lines; fields of
Grade 8: electrical equations: V = IR,
P = IV
Course of the lesson
stages of the lesson
activities at the lesson
the topic of day and spelling out the learning outcome they will possess
after the study.
1. Organizational moment to
acquaint students with the
theme of the lesson
objectives of the lesson
criteria of success for the lesson
plan of events for the lesson
Motivation. Thompson’s experiment
Thomson’s role in the discovery of the electron, it
to be interested to study of the new material.
ØIn 1897 JJ
Thomson set out to prove that cathode rays originating from a heated cathode
(electron gun), were actually a stream of small negatively charged particles
accelerated from the cathode.
deflected by electric and magnetic fields.
ØThe beam of
electrons strikes a fluorescent screen.
ØToday we will
learn more together about it!
(W) Whole class
The study of the new material is based on the
explanation of the topic by the teacher accompanied by a presentation.
Use the fine beam tube video to
derive a value for e/m.
Discussion: Velocity selectors and mass spectrometers There is a wide range of these both of working principles. Again
there is a chance to compare the effects of electric and magnetic fields. If
students are studying chemistry, you can draw on their knowledge of mass
spectrometers to emphasise the value of these techniques.
of calculations based on the velocity selector can be used to test
understanding of the underlying principles and use of equations.
Write your answers in the spaces
provided. Use these data:
of the electronic charge = 1.6 × 10–19 C
of electron = 9.1 × 10–31 kg
force on an electric current in a magnetic field is perpendicular to both the
current and the field. This diagram may help you.
beam of particles passes in a straight line from a source X, to a spot, E, on
a fluorescent screen. When the electromagnet shown is switched on, the beam
hits the screen at one of the spots A, B, C, D or E.
which direction does the beam bend if the particles are positively charged?
does it go if the particles are neutral?
happens to the positively charged particles if the magnetic field is
one form of mass spectrometer, charged ions in the beam fan out, moving in
the paths shown in the diagram. Parts of the paths include a magnetic field
whose direction is perpendicular to the plane of the paper.
places where there must be no magnetic field in the direction suggested. Do
not use shading.
the area where there must be a magnetic field.
is the shape of the path followed by a proton that is projected into a
uniform magnetic field at right angles to its velocity? Justify
diagram shows the initial path of an electron fired into a uniform magnetic
field. The magnetic field is at right angles to the direction of the electron
and is directed away from the reader.
a labelled arrow to the show the direction of the force on the electron.
the subsequent path of the electron.
uniform electric field is produced by maintaining a potential difference of
1000 V across a pair of parallel plates 5 cm apart. An electron enters the
field at right angles as shown with a velocity of 4.0 107 m s–1 and emerges from the plates without hitting them.
in the path of the electron on the diagram.
name is given to this type of path?
that the left-hand motor rule works for conventional current.
that the left-hand motor rule works for conventional current.
At the end of
the lesson, learners reflect on their learning:
has been learned
is necessary to work on
the learners could evaluate their own work as well as the work of their
classmates using certain criteria.
– how do you plan to give more support? How do you plan to challenge the more
– how are you planning to check students’ learning?
and safety regulations
will watch the video
take information from the texts
by questioning and dividing in group
with varied difficulties
Assessment – how
are you planning to check students’ learning?
The output for
the worksheet will serve as assessment
the lesson will also serve as formative assessment.
Be careful when use the laser-coder
the lesson objectives/learning objectives realistic? Did all learners achieve
my planned differentiation work well?
I stick to timings?
changes did I make from my plan and why?
Use the space below to reflect on your lesson.
Answer the most relevant questions from the box on the left about your
What two things went really well (consider both
teaching and learning)?
What two things would have improved the lesson
(consider both teaching and learning)?
What have I
learned from this lesson about the class or achievements/difficulties of
individuals that will inform my next lesson?
Lesson plan Long-term plan unit:
Type of differentiation Differentiated poster-session ,
W) Whole class work. The study of the new material is based on the explanation of the topic by the teacher accompanied by a presentation