Q1 · 2024 · Paper 2Simple familiar4 marks
QUESTION 1 (4 marks)
A coil of wire with 100 turns and a radius of 1.4 cm is placed perpendicular to a magnetic field of strength 0.510 T. The magnetic field strength is then changed to 0.030 T in 0.020 s. Calculate the magnitude of electromotive force (emf) induced in the coil. Show your working.
Magnitude of emf = V
WORKED SOLUTION
4 marksQCAA guide · typeset solution
ANSWER
See worked solution below.
Worked solution
r = 1.4 cm = 0.014 m
2
2
2
4
1
0.0
6. 6 1
14
0 m
r
A
π
π
−
=
×
=
×
≈
(
)
(
) (
)
4
emf
1.48
100
0.030
0.510
6.16 10
0.020
n
BA
t
⊥
−
= −
×
−
×
×
=
−
∆
∆
=
Magnitude of emf = 1.5 V
• converts the radius to SI units (from cm
to m) [1 mark]
• determines the area of the coil [1 mark]
• recognises the scenario relates to
induction of an electromotive force by
using the equation [1 mark]
• calculates emf [1 mark]
One QCAA sample method typeset for web; criterion wording is adapted from the official marking guide.
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Compare your working with the guide above.