Faraday’s and Lenz’s laws
Electric field strength
−d(Nϕ)
E =
F dt
E =
Q
Root-mean-square values
Q
E =
4πε r2 V
Question
Physics
CAIE2024
field strength E at P due to sphere X.
X
E = ......................................................... [1]
X
(iii) Determine an expression, in terms of Q, x and ε, for the resultant electric field strength
Question
Physics
CAIE2024
field strength E at P due to sphere X.
X
E = ......................................................... [1]
X
(iii) Determine an expression, in terms of Q, x and ε, for the resultant electric field strength
Question
Physics
CAIE2024
(a) State Coulomb’s law.
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [2]
(b) Fig. 6.1 shows an isolated hollow conducting sphere that is positively charged.
+
+ +
+ +
+ +
+
Fig. 6.1
On Fig. 6.1, draw field lines to represent the electric field outside the sphere. [3]
(c) Fig. 6.2 shows the variation of the electric field strength E with distance x from the centre of
the sphere in (b).
Question
Physics
Edexcel2024
Turn over
PMT
(b) The power supply output is increased until sparks are heard and are seen in the
gap between the plates. Sparks form in air when the electric field strength exceeds
Question
Physics
Edexcel2023
Faraday’s and Lenz’s laws
Electric field strength
−d(Nϕ)
E =
F dt
E =
Q
Root‑mean‑square values
Q
E =
4πε r2 V
Question
Physics
Edexcel2023
*P71915A01328*
Turn over
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AREA
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AERA
SIHT
NI
ETIRW
TON
OD
AERA
SIHT
NI
ETIRW
TON
OD
AERA
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NI
ETIRW
TON
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PMT
(ii) Complete the free‑body force diagram for support rod X.
(2)
weight of cable
(b) A website gives a value of the electric field strength E, at two distances from the
electric cable.
Distance / m E / N C–1
Question
Physics
Edexcel2023
*P71915A0928*
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PMT
E
(c) The resistivity ρ of the conducting material is given by ρ =
j
where E is the electric field strength.
Show that the units are the same on both sides of this equation.
(4)
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(Total for Question 12 = 7 marks)
*P71915A01028*
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AERA
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ETIRW
TON
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TON
OD
PMT
Question
Physics
Edexcel2022
Faraday’s and Lenz’s laws
Electric field strength
−d(Nϕ)
E =
F dt
E =
Q
Root‑mean‑square values
Q
E =
4πε r2 V
Question
Physics
Edexcel2022
The graph shows how the potential V varies with distance d in an electric field.
V
d
Which of the following shows the corresponding variation in electric field strength E?
E E
d d
A B
E E
d d
C D
(Total for Question 6 = 1 mark)
Question
Physics
Edexcel2021
A potential difference is applied across two parallel plates. A particle carrying a charge
of +0.1 C is placed between the plates and experiences a force F.
The distance between the plates is halved. The potential difference remains constant.
Which of the following is now equal to the electric field strength between the plates?
A 5F
B 10F
C 20F
D 40F
(Total for Question 8 = 1 mark)
Question
Physics
Edexcel2021
Faraday’s and Lenz’s laws
Electric field strength
−d(Nϕ)
E =
F dt
E =
Q
Root-mean-square values
Q
E =
4πε r2 V
Question
Physics
Edexcel2020
The graph shows how an electric potential V varies with distance x.
V
x
Which of the following shows the corresponding variation of electric field strength E
with x?
E E
Question
Physics
Edexcel2020
Faraday’s and Lenz’s laws
Electric field strength
−d(Nϕ)
E =
F dt
E =
Q
Root-mean-square values
Q
E =
4πε r2 V