12AP - Unit 2 Test - Electromagnetism XXXXXXXXXXpages
Grade 12AP Physics 2020 – 2021 Name: _____________________________
Unit 2 Take-Home Test Assignment - Electromagnetism
Instructions: 1. Answer all questions clearly numbered on paper of your choice.
2. You may use a calculator, a writing implement and a ruler.
3. For quick reference, you can use the provided formula page (at the
end of the test assignment).
4. Part marks may be assigned, but only if your work is shown.
5. Always remember to fully explain your reasoning.
6. This is due on Thursday, March 11th, 2021 (by end of day).
1. Examine the circuit shown below. (9 marks)
(a) Determine the total equivalent capacitance for this complex circuit – show at least 2
steps in your simplification process. (5 mks)
(b) Determine the total charge stored in the
simplified equivalent circuit you found in
part (a). (1 mk)
(c) In a capacitor, the area of the
plates is and the separation
distance between capacitor plates is
. Calculate the dielectric
constant XXXXXXXXXXmk)
(d) Describe how it is possible to halve the capacitance of a given capacitor without altering
the area of the plates or the dielectric constant value XXXXXXXXXXmk)
2. A solenoid coil is connected to a strong DC voltage source as shown below. In addition a
length of wire is suspended horizontally
across the opening of the solenoid at the
ight side. The solenoid coil has a diameter
of . (7 marks)
(a) Label the ‘magnetic poles’ of the
solenoid AND determine the
direction of the cu
ent flowing in the
wire coils of the solenoid (indicate it
clearly on the diagram or provide a
ough sketch in your answer). (2 mks)
(b) A DC cu
ent of is passed
through the wire suspended in front of
the solenoid (at the right end) and it is
6.2 µF
2.45 m 2
0.28 mm
κ
16.4 cm
64.5 A
36V
3 µF
1.5 µF
0.6 µF
2 µF
3 µF
3 µF
29
pulled downwards with a force of . Label the direction of cu
ent flow in the
wire (or in your rough sketch) AND determine the strength of the magnetic field B at
the opening of the solenoid (where the wire passes). (3 mks)
(c) If the cu
ent flowing through the wire suspended in front of the solenoid opening was
switched to being AC cu
ent instead (the cu
ent in the solenoid remains DC), how
would the wire across the opening of the solenoid behave? (2 mks)
3. A charged particle is fired
directly towards a long,
straight conducting wire
that is fixed in place. The
cu
ent in the wire is
flowing upwards in the ‘Top
View’ shown in the diagram
and into this page in the
‘Side View’ diagram. The
charge moves in the plane
of the paper (in both
diagrams) at high speed.
(see diagram at the right).
(7 marks)
(a) Sketch in the magnetic field created by the wire (in both diagrams) and then describe
the path taken by the particle as it approaches the wire. Explain
iefly by refe
ing to
any forces, directions, and consequences to its motion and include a sketch of its
motion on the diagram. Also, make sure to distinguish between the path(s) of
positive, negative and neutral particles. (4 mks)
(b) The magnetic field strength at a location r metres from conductor (measured
perpendicular) with cu
ent I is given by the formula below (where is the vacuum
permeability constant). If the magnetic field strength is at a distance of ,
determine the cu
ent flowing in the wire. (1.5 mks)
where
(c) Suppose the particle has a charge of , a mass of and
is moving at a speed of towards the wire. Determine the magnetic
force it experiences when it is at a distance of from the wire. (1.5 mks)
4. A rectangular cu
ent loop is placed between two large permanent magnets. The magnetic
field flows downwards, perpendicular to the page and has a strength of . The loop is
connected to the end of a shaft that can rotate around an axis in the plane of the page (and
passes through the centre of the rectangular loop) and oriented horizontally. The cu
ent
loop measures wide and tall. See the diagram below: (6 marks)
4.8 N
µ 0
1.12T 5.2 cm
B =
µ 0
2π
⋅ I
µ 0 = 4π ×10
−7 T ⋅m A
+ 4.806 ×10 −19 C 3.308 ×10 −27 kg
2.25 ×108 m s
3.6 ×10 −4 m
2.88 T
16.4 cm 10.5 cm
(a) Determine the magnetic flux, , passing
through the cu
ent loop as shown in the
diagram. (1.5 mks)
(b) The loop is forced to rotate around the axis in a
counter-clockwise direction as seen from the
left side of the page looking to the right along
the axis of rotation (bottom edge rises up and
out of the page while the top descends below
the page). It rotates with a period of .
Determine the change in the magnetic flux
through the loop once it has been rotated half-
way through one complete revolution (that is,
calculate XXXXXXXXXXmk)
(c) Determine the strength of the emf (voltage) created in the wire loop as a result of its
forced rotation described above. (1.5 mk)
(d) At the instant the loop is in the plane of the page (the diagram above), what direction
will the induced cu
ent move in the loop while the emf (voltage) is being created?
(clockwise or counter-clockwise) Explain your reasoning. (1.5 mks)
Φ B
0.25 s
ΔΦ B