MNS Department
Semester: Summer, 2023; Course No: PHY 112
Course Title: Principles of Physics II
Time: 30 min
Date: 9 July, 2023
Consider it for all problems:
q1= Sum of the first 3 digits of your ID
q2= Sum of the last 3 digits of your ID
Q= q1 + q2 + q3
q3= Sum of the first and last digits of your ID
d1= 1st digit of your ID
d2= 2nd digit of your ID
m = sum of your middle two digits.
1. The electric field in an xy plane produced by a single particle is
(12 i^ +3 ^j) N /C at the
^
point (q 1 , q 2) and 50 i N /C at the point (d 1 , q 3) m .The particle is positively charged.
What are the x and y coordinates of the source particle of the electric field?
2. A particle with charge q 1 nC is located at the origin. Two particles, with charges of q 2 nC and
−q3 nC are placed at the points with coordinates (0, 4.00 cm) and (0,−4. oocm) .
a) Determine the electric potential energy of the configuration of the three fixed charges.
b) A fourth particle with mass m kg and charge 10 nC, is released from the rest at the point (3cm,
0). Find its speed after it has moved freely to a very large distance away.
3. The electron and proton of a hydrogen atom having the same amount of charges but opposite
type, are separated by a distance of approximately d 1∗10−11 m . Find the magnitudes of the
electric force and the gravitational force between the two particles.
4. An electron enters the region of a uniform electric field. Initial value of the velocity is
6
v i =3∗10 m/ s and E=Q N /C . The horizontal length of the plates is ι=4 cm .
a) Find the acceleration of the electron while it is in the electric field.
5. A electric dipole is placed in a uniform electric field of magnitude
Q∗105 N /C that is directed parallel to the plane of the figure. The
charges are ±e C ; both lie in the plane and are separated by the
1.25 nm. Find (a) the net force exerted by the field on the dipole; (b)
the magnitude and the direction of the electric dipole moment; (c)the
magnitude and the direction of the electric dipole moment; (c) the
magnitude and the direction of the torque; (d) the potential energy of the
system in the position shown.