Time Duration : 120 Mins.
1)
A small test
sphere of mass 60 gr is suspended from a string of
length 10 cm. At a distance ℓ of 10 cm from the
point of
suspension and a distance ℓ/2 from the string is
a fixed
sphere as shown in figure 1. The spheres have equal
charges
of the same polarity. Calculate the charges on each
sphere
if the string is deflected by 30 0 ? (25
points)
2)
At some instant
the velocity components of an electron moving between two charged parallel
plates are vx=2x105 m/sec and vy=0.5x104
m/sec. If the electric field between the plates is given by E = 2.1x104 ĵ N/C. (Neglect the effect of the g)
(a) What is the acceleration of the electron ? (10 points)
(b) When the x-co-ordinate of the electron has changed by 3
cm what will be the velocity of the electron ? (15 points)
3)
5.4.1999
(a) Consider two
concentric spherical shells of uniform
surface charge densities sa
and sb
and radii a and b, b>a.
Develop expressions for E in the regions inside the
inner
shell, between the two shells and outside the outer
shell.
What should the ratio of the total charges and their
relative signs to be for the field to be zero outside
b. (18 points)
(b) A cone is replaced in a region of uniform electric
field
E=10 k N/C
(Fig.2). Determine the electric flux for each of
the surfaces.(7 points)
Figure
2
4) Four charges
of 1 mC are placed on the
corner of a rectangle of sides having length 6 cm and 8 cm.
(a)
Find the electric
field at the center of the rectangle. (8 points)
(b)
Calculate the
potential at the center of the rectangle. (8 points)
(c)
What is the
electric potential energy of the given charge configuration. (9 points)
Inst.Metin BEDİR
Asst.Prof.Dr.A.Necmeddin YAZICI
Asst.Prof.Dr.Ramazan KOÇ
Useful Constants:
k=9x109 Nm2/C2; 1 μC=1x10-6 C me=9.1x10-31 kg, e=-1.6x10-19 C, sin300=1/2; cos300=√3/2;
Time Duration : 120 Mins.
1.
Two similar
charges each have a mass of 10 g. How great a charge should be placed to
counter balance the gravitational force between the charges. The distance
between the charges is much greater than their radii. (G=6.67x10-11
Nm2/kg2)
2.
A charge of 8x10-5
C is placed in an electric field by Ex=3x103 N/C, Ey=-600
N/C, and Ez=0.
a-)
What are the magnitude and direction of the force on the charged particle.
b-)
If the particle starts from rest at the origin, what will be its co ordinates
after 3 sec.
(Take mass of
the particle m=10 g.)
3. A thick spherical shell has a charge Q, an inner
radius a, and an outer radius b. The charge distribution between a and b is spherically symmetric but varies with distance from the center
: ρ=A/r, where A is a constant. A point charge q is placed at the center of the sphere.
a-) Determine q in terms of Q, a, and b such that the field between a
and b is independent of r.
b-) What is
the field for r<a ?
c-) What is
the field for r>b ?
4. A positive charge q is distributed uniformly throughout a non conducting spherical
volume of radius R. Calculate the
potential inside the sphere.
Useful Constants:
k=9x109 Nm2/C2;
1 μC=1x10-6 C me=9.1x10-31
kg, e=-1.6x10-19 C,
Inst.Metin BEDİR
Asst.Prof.Dr.A.Necmeddin YAZICI
Asst.Prof.Dr.Ramazan KOÇ
Time Duration : 120 Mins.
Q-1-) Two uniform line
charges, each of length 2l,
are replaced parallel
to each other.
a-)
Determine the magnitude of electric
field intensity at point
P and then indicate
the direction of E
(Fig.1a).
b-)
What is the magnitude and direction of
force on the suspended
pith ball that has
charge Q=260e located at
this point P (Fig. 1b).
(l=4 cm, x=3 cm,
l=1x104
C/m)
Q-2-)
Consider a solid sphere of radius a=3 cm that carries a
negative charge of 2 mC distributed
uniformly. The sphere
is placed concentrically in a spherical
shell of radius
b=8 cm that has a positive charge of 5 mC distributed
uniformly over it. Calculate the
electric field by using the
Gauss’s law at the regions (a) r=1
cm, (b) r=5 cm, and (c) r=10 cm.
Q-3-)
Along the x-axis, indicated by the dashed line on this diagram,
the electric field is , where c is a
positive constant,
and is a unit vector.
This minus sign indicates that the field
points “backwards” towards x=0. Ignore gravity. A particle
of
charge +q0 and mass m is released from rest at
x=+x0 on the
x-axis. What is the particle’s speed when x=0 ? Solve the
question in terms of q0, m , c and x0.
b-)
A parallel-plate capacitor having 10 x 20 cm2
dimensions
and
the distance between plates is 2 mm and they are
charged
with a potential 500 V. Find,
i-)
the capacitance C
ii-) the magnitude of charge Q on each plate
iii-) the stored energy U
iv-) the electric field E between the plates
v-) the energy density u between the
plates.
Time Duration : 120 Mins.
Q-1-) a-) Prove that the voltage across a capacitor during
a charging phase (position 1) in an RC circuit
(in below figure) is given by the relation
VC(t)=V0
(1-exp(-t/RC))
b-)
Find the mathematical expression of the voltage and
current for the capacitor in below figure and then
determine Vc and ic at
100 msec.
Q-2-) a-) An automobile battery has a potential difference of
12.0 V and sends current through a circuit of total resistance 1.5 W that contains a copper wire 1. 0 m long with an 0.3
cm2 cross-sectional area. Find (a) the current through the
wire, (b) the energy lost to heat in the circuit in one hour and (c)
the distance travelled by an electron in the circuit in one hour. (MCu=63.5
gr/mole, NA=6.02x1023 mole-1, r=8.91x103 kg/m3)
Q-3-) A proton is moving in a positive x-direction as it
enters a region of
uniform magnetic field of 0.4 Tesla directed
vertically down.
The proton starts to follow a circular path of a
radius 10 cm in
this magnetic field.
a-)
Draw path of the proton in this uniform magnetic field.
b-)
Determine the momentum and speed of the proton.
c-)
If the proton is initially accelerated under the
potential difference 12 kV into the same magnetic
field, what will be radius of the path of the proton.
(mp=1.67x10-27 kg, e=1.6x10-19
C)
Q-4-) Two long and thin straight
wires carry currents at
opposite direction as shown in figure. Find the
magnitude of magnetic field and directions at
the points P1 and P2 using
Amper’s law.
Inst.Metin BEDİR
Asst.Prof.Dr.A.Necmeddin YAZICI
Asst.Prof.Dr.Güler YILDIRIM
Assoc.Prof.Dr.Zihni ÖZTÜRK
Time Duration : 120 Mins.
Q-1-) For the given system (Fig.1)
a-) What
is the electric field E at the center of the system.
b-)
What is the electric potential at the center of the system.
c-)
Assume that you bring a fifth charge (Q5=10 pC) very
slowly from infinity to the center of the system. How
much
work must you do?
d-)
What is the electric force acting on Q5.
e-)
What is the potential energy of the charge Q5.
Q-2-) Consider a spherical uniform
volume charge density r
with Q=61 nC and r0=48 mm.
a-) Determine
the volume charge density r.
b-)
Find the electric field E at point r=24, 48, and 96 mm
from the center of the shere.
Q-3-) For the given non conducting
system (Fig.3)
a-) What
is the electric potential of sphere 2.
b-) What
is the electric potential difference
between sphere 2 and 1.
c-) What
is the potential of sphere 1.
d-) Assume
that a tiny particle of charge
q=4.0 mC and mass m=2.0x10-8 kg is released
from rest from the surface of the sphere 2. What
velocity does the particle have when it reaches
a distance 2r3 from the center of sphere 1.
Q-4-) Three identical coaxial cable (cylindrical) capacitor
are connected as shown in figure 4.
a-) Find
the capacitance of one capacitor.
b-) Find
the equivalent capacitance of the system.
c-) What
is the charge on each capacitor.
d-) What
is the potential difference across each
capacitor.
Inst.Metin BEDİR
Asst.Prof.Dr.A.Necmeddin YAZICI
Time Duration : 120 Mins.
rectangular which is the
length of long side is three
times longer than short
side. A charge q is placed at each
of the other two corners.
a-)If the net electrostatic force on each Q is zero,
what is
Q in terms of q ?
b-)What is the total potential energy of the system in
terms of q ?
c-)What is the electric potential on each Q?
d-)Is there any value of q that makes the net
electrostatic
force on each of the four charges zero? Explain.
radius R1 with
a total charge +q is surrounded by a
non-conducting
cyclindrical shell of inner radius
R2 outer
radius R3 with total charge –2q. Use
Gauss’s law to find the
electric field at
a-) r<R1
b-) R1<r<R2
c-) R2<r<R3
d-) R3<r
the opposite charged
parallel plates. The
mass of the particle is
10-27kg and its
charge is 1.2x10-9
C which is fired with an
initial velocity 106
m/sec and 370 with
horizontal direction.
When the particle is
taken away 12 cm along
the horizontal
direction as shown in figure, determine the
electric field between
the parallel plates.
r=0.4R; the ring has a
uniform surface charge
density s with V¥=0 Volt at infinity, find an
expression for the
electric potential at point
on the central axis of
the ring.
b-) If a point charge is located at point z=2R,
what is the potential energy of the system.
plates of 6 cm radius and is filled with
two dielectric materials
with dielectric
constants k1=0.1
and k2=0.2,
respectively.
The plate seperation
distance is 2 mm.
The system is connected a
potential
difference of 200 volts.
Determine
a-) the capacitance of the system
b-) the magnitude of charge on each plate
c-) the stored energy on each capacitor
d-) the potential difference across each capacitor.
Time Duration : 120 Mins.
1.
a-) The current density across a cylindrical copper wire
of radius R0 varies according to the equation
where r is the distance from the central axis.
Calculate the current (I) in terms of J0, cross sectional
area and radius R0 of conductor.
b-)
Suppose that cross sectional area and length of the wire is equal to 3.14 mm2
and 314 m. Calculate the resistance R, current I, current density
J, conductivity s, electric field E when J0=1.33x103
A/m and r=1.72x10-8 W-m.
2.
What is the potential difference across the resistance
Rx in below Figure.
3.
a-) What is the
current and voltage across the
capacitors and resistor R3 in below figure
at t=20 msec
in position 1.
b-) Assume that after t=20 msec, the switch S is
suddenly passed into position 2, What is the current
and voltage across the resistor R3 after the switch
passing position 2 at t=10 msec.
4.
A positively charged particle (q=e, m= 6.7x10-27
kg) is
accelerated by potential difference V0=20
volt and
allowed to enter a magnetic field as shown in below
figure. In the field it moves in a semicircle path,
and
striking a photographic plate at distance x=20 cm
from the entry slit.
a-)
Draw the direction of the particle in the magnetic
field region.
b-)
Determine the kinetic energy and velocity of the
charged particle.
c-)
Find the magnitude of the magnetic field B.
5.
In below figure,
two long wire which are lying
along the left and right side of a rectangular
loop carrying currents I1=10 A and I2=15
A,
respectively. The rectangular loop carries a
current of 5 A. What must be ratio of a/c to
obtain zero force on the rectangular loop?
Inst.Metin BEDİR
Asst.Prof.Dr.A.Necmeddin YAZICI
11/06/2001
EP106 RETEST EXAM
Duration: 100 min
Q-1) A copper wire and
an iron wire of equal length L and diameter d are joined and a
potential difference V is applied
between the ends of composite wire. Calculate: a) The
electric field strength in each wire.
b)The current density in each wire. c) The potential
difference across each wire. Assume
that L=10m, d=2.0 m and V=100 Volts.
Q-2) Two long parallel
wires 5.00cm apart carry 20.0 A currents in the same direction.
Determine the magnetic field strength
at a point 12.0 cm from one wire and 13.0 cm
from the other. ( Hint: Make a drawing
in a plane containing the field lines and recall the
rules for vector addition.)
Q-3) a) What is the
total resistance in below circuit ?
b) What is the passing current
through the resistance Ra ?
c) Indicate the direction of current
in this resistance.
Q-4) For given network;
a) What is the RC time constant of this circuit ? b) Calculate the
potential difference across the each
capacitor at time t=5 msec.
11/06/2001
EP 106 FINAL EXAMINATION
Duration:110 min
Q-1)
A wire with a resistance of 6.0W is drawn out so
that its new length is three times its original length. Find the resistance of
the longer wire assuming that the resistivity and density of the material are
not changed during the drawing
process.
Q-2)
An infinitely a long wire has uniform line charge distribution
and its line charge density is l(C/m). Find the potential difference
between the two points a and b.
Q- 3) A thick
spherical shell has a charge Q, an inner radius
r1
and an outer radius r2. The charge distribution
between
r1 and r2 is spherically symmetric but
varies
with a radialdistance from the center
r=C/r, where C is a
constant and r is the
variable
distance from the center of the
shell.
In addition, a point charge q is located
at
the center of the shell.
a)
Determine
q in terms of Q,r1 and r2 such that the electric field
between r1 and r2 is to be uniform.
b)
What should the value of C be so that the
electric field in the region r1<r<r2
has constant magnitude.
c)
What is the electric field for r<a and r>b ?
Q-4 )
In the coaxial cable given in figure, a straight wire of
radius
a carries a current I1 along the axis of a metal tube
with
inner radius b and outer radius c. The tube carries a
current
I1 in a direction oppposite to that in the wire. Find
the
magnetic field; a) r<a, b)
a<r<b, c) r>c.
Q-5)
Determine the magnetic field at the center of a current carrying
square loop of length a as shown below.
03/10/2000
EP
106 RETEST EXAM.
Duration:100 min
Q-1) Four charges of 1mC are placed on
the corner of a rectangle of sides having length 6 cm
and 8 cm.
a)-Find the electric field at the
center of the rectangle.
b)- Calculate the potential at the
center of the rectangle.
c)- What is the electric potential
energy of the given charge distribution.
Q-2) Prove the capacitance
and energy density expressions for the parallel plate capacitor and
the solve following problems. A parallel plate air capacitor has circular
plates of 8 cm
radius and spacing of 2 mm is charged
to a potential of 200 volts.
Find: a)- the capacitance value of
the capacitor,
b)- the magnitude of the charge on
each plate,
c)- the stored energy,
d)- the electric field between the
plates,
e)- the energy density between the
plates.
Q-3) A thick spherical
shell of uniform charge density r=r0
,
inner radius R0 outer
radius R1. Find:
a)- the electric field for r<
R0 , R0 <r<R , r
>R1 .
b)- the work done to move a charge Q
from 4R1 to 2R1.
Q-4) A 10 keV electron moving horizontally enters of space in
which there is a downward direction electric field of magnitude 10 kV/m.
a)- What are the magnitude and direction of the magnetic
field that will allow the electron to continue to move horizontally ? ( Ignore
the gravitational force ).
b)- Is it possible for a proton to
pass through this combination of fields undeflected ?
Q-5) Find the current
in each resistor and potential difference between a and b.
EP 106 GENERAL PHYSICS
(Ek Sınav) 25/09/2001
Duration:120 min.
Q-1)
The charge -Q shown at the at the right is a distance y (not very
small)
above the origin and moving downward. Find (a) the
electric
potential it feels, (b) its potential energy, (c) will it
be
moving faster or slower when it reaches the origin. Explain.
Q-2)
A sphere of radius 6 cm has a volume charge density r= 2x103C/m3,
and
is surrounded by a thin metal shell of radius 8 cm whose surface
charge
density s
= 1x102 C/m2.
Calculate the electric field at
r=3
cm, r=7 cm, and r=10cm.
Q-3)
A 20 cm long wire has a uniform charge density, l=3.00
C/m. It is
along
the y-axis centered in the origin as shown in figure. Find the
electric
potential at a distance a=10 cm from the origin.
Q-4).Find
the current and voltage across the resistance Rx in below figure.