Department of Applied Physics and Astronomy
College of Sciences
University of Sharjah
Course Name
Physics 2
Course ID
1430117
Semester
Fall 2024/2025
Exam
Midterm Exam
Place
Date
21 October 2024
Time
18:30 – 19:30
Instructor
Student’s name:
ID:
Section:
MCQ
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Answer
A
C
B
B
C
C
D
A
C
B
E
A
D
E
MCQs
Mark Assigned
30
Total
30
Mark Obtained
**Please read the following instructions carefully:
a. The exam comprises six pages (including the cover page and formulas sheet).
b. The exam comprises 14 MCQs: only 12 correct answers are needed for a full mark.
c. Show your work for all questions. Marks may not be credited if correct answers are not
supported by correct solution.
d. Indicate your answers using a pen in the table above.
e. Mobile phones must be switched off and placed outside the exam room.
f. Never start solving your exam until you are instructed to start.
g. No extra white sheets are allowed. Use the back of the exam sheets for your draft.
1
Q1. Four-point charges are placed on the xy-plane as shown. Calculate the magnitude of the net force
acting on q2. Given q1 = q2 = 3 μC, q3 = – 3 μC, and q4= – 6 μC.
A) 1.86 N
B) 23.15 N
C) 78.20 N
D) 11.33 N
E) 8.45 N
Q2. The electric field produced by a charged non-conducting sphere is greatest
A) at its center.
B) at all points inside the sphere.
C) on its surface.
D) outside the sphere.
E) Nowhere
Q3. The figure shows an infinite line with uniform linear charge density λ = 10 nC/m and a ring with
charge Q = 4.0 nC uniformly distributed over it and radius r = 4.0 cm. Find the magnitude of the electric
field at the point P.
A) 11.34 N/C
B) 50.94 N/C
C) 21.55 N/C
D) 9.78 N/C
E) 79.33 N/C
2
Q4. The diagram shows the electric field lines due to two charged parallel metal plates. We
conclude that:
A)
B)
C)
D)
E)
the upper plate is positive and the lower plate is negative
a proton at X would experience the same force if it were placed at Y
a proton at X experiences a greater force than if it were placed at Z
a proton at X experiences less force than if it were placed at Z
an electron at X could have its weight balanced by the electrical force
Q5. The diagram shows two identical particles, each with positive charge Q. The electric
field at point P on the perpendicular bisector of the line joining them is:
A)
B)
C)
D)
E)
↑
←
→
↓
Zero
Q6. A uniform electric field of 300 N/C makes an angle of 25° with the dipole moment of an
electric dipole. If the torque exerted by the field has a magnitude of 2.5 × 10–7 N m, the
dipole moment must be:
A)
8.3 × 10–10 C m
B)
9.2 × 10–10 C m
C)
2.0 × 10–9 C m
D)
8.3 × 10–5 C m
E)
1.8 × 10–4 C m
Q7. Two charges of -65 pC and +40 pC are inside a cube with sides that are of 0.70-m length.
Determine the net electric flux through the surface of the cube.
A) +2.8 N  m2/C
B) –1.1 N  m2/C
C) +1.1 N  m2/C
D) –2.8 N  m2/C
E) –0.47 N  m2/C
3
Q8. Charges q and Q are placed on the x axis at x = 0 and x = 2.0 m, respectively. If q = 30 pC and Q =
-15 pC, determine the net flux through a spherical surface (radius = 1.0 m) centered on the origin.
A) 3.4 N  m2/C
B) 1.3 N  m2/C
C) –8.5 N  m2/C
D) –3.4 N  m2/C
E) –1.3 N  m2/C
Q9. Rank the electric flux (highest to lowest) through the different surfaces (S1, S2, S3, and S4) shown
in the figure below.
A) S1>S2=S4>S3
B) S3>S1>S4=S2
C) S2>S3=S4>S1
D) S4>S2=S1>S3
E) S1>S4>S2>S3
Q10. A point charge creates an electric potential V= - 25.7 V at a point 1.5 m away. What is the value of
the charge?
A) 5.7 nC
B) - 4.3 nC
C) - 8.6 nC
D) 12.1 pC
E) 9.1 pC
Q11. Two large parallel insulating sheets separated by a distance 0.3 m. They carry charge densities 1=
4 pC/m2 and 2= -7 pC/m2, as shown in the figure. Find the electric field between them at a distance
0.1 m from the left sheet.
A) 1.5 N/C
B) 11.1 N/C
C) 9.3 N/C
D) 5.4 N/C
E) 0.6 N/C
4
Q12. Four points (a, b, c, and d) exist inside a region of uniform electric field E as shown in the figure.
Rank the electric potential V at these points (lowest to highest).
A) Vb = Vc < Vd < Va
B) Va = Vb < Vc < Vd
C) Vb < Vd < Vc < Va
D) Vd < Vc < Vb = Va
E) Vb < Vd = Vb = Va
Q13. Find the total potential energy of the three charge setting at the corners of the shown equilateral
triangle, where Q1= 3 μC, Q2= -5 μC, Q3= 8 μC, and d = 0.1 m.
A) 2.8 J
B) - 9.3 J
C) 14.6 J
D) -2.8 J
E) 9.3 J
Q14. The electric potential in a region of space is given by V(x,y,z) = 2 x + 4 y x2 - 6 y2 z3. What is the
electric field (in N/C) at the origin (0,0,0)?
A) 3 i + 5 j
B) - 9 j
C) - 2 i + 5 j - 2.8 k
D) - 5 i + 3 k
E) - 2 i
5
Equations Sheet
𝜀0 = 8.85x10−12 C2 /N. m2
𝑚𝑒 = 9.1 × 10
1
𝐹 = 4𝜋𝜀
−31
𝑘𝑔
𝑞1 𝑞2
𝑒 = 1.6x10−19 𝐶
𝑚𝑝 = 1.67 × 10−27 𝑘𝑔
𝐹𝑛𝑒𝑡 = 𝑚𝑎
0
1
2
0 𝑟
𝑞
𝐸 = 4𝜋𝜀 𝑟 2
𝜏⃗ = 𝑝⃗x𝐸⃗⃗
𝜏 = 𝑝𝐸𝑠𝑖𝑛(𝜃)
𝑈 = −𝑝⃗. 𝐸⃗⃗
0
𝑝 = 𝑞𝑑
1
1
𝑘 = 4𝜋𝜀 = 8.988 x 109 𝑁. 𝑚2 /𝐶 2
𝑝
𝜎
𝐸 = 2𝜋𝜀 𝑥 3
𝑧
𝐸 = 2𝜀 (1 − √𝑧 2
0
0
𝑄
⃗⃗⃗⃗⃗⃗ = 𝑒𝑛𝑐,
𝜙 = ∮ 𝐸⃗⃗ . 𝑑𝐴
𝜖
0
𝜎
𝐸=𝜀
+𝑅 2
𝐹⃗ = 𝑞𝐸⃗⃗
1
)
𝜆
𝐸 = 2𝜋𝜀 𝑟
0
𝑥𝑄
𝐸 = 𝑘 (𝑥 2 +𝑎2)3/2
𝜎
𝐸 = 2𝜀
0
0
v = v0 + 𝑎𝑡
1
𝑥 − 𝑥0 = v0 𝑡 + 𝑎𝑡 2
2
v 2 = v02 + 2𝑎(𝑥 − 𝑥0 )
1
𝑥 − 𝑥0 = (v0 + v)𝑡
2
𝑊 = −∆𝑈 = −𝑞∆𝑉
1
𝑞
𝑉 = 4𝜋𝜀 𝑟
0
1
𝑈 = 4𝜋𝜀
𝑞1 𝑞2
0
𝑟
𝑈 = 𝑞𝑉
𝑊𝑎𝑝𝑝 = 𝑞(𝑉𝑓 − 𝑉𝑖 )
1
𝑞
1
𝑉 = 4𝜋𝜀 𝑟
𝑑𝑞
𝑉 = 4𝜋𝜀 ∫ 𝑟
0
0
𝜕𝑉
𝜕𝑉
𝐸𝑥 = − 𝜕𝑥
𝐸𝑦 = − 𝜕𝑦
6
𝜕𝑉
𝐸𝑧 = − 𝜕𝑧