Electricity and Magnetism Answers

on cathode ray oscilloscope,the distance between crests is 2cm.if the time base is set at 10ms/cm.what is the period of the wave

An electron beam passes un deflected with
uniform velocity v through two parallel
plates, when a magnetic field of 0 01 T is
applied perpendicular to an electric field
between the plates produced by a p d of
100 V The separation of the plates is 5 mm
Calculate the velocity?

Briefly explain the motor effect, including the direction of deflection (motion). Your response should include five main points about the motor effect.

An AM radio antenna pi
ks up a 1000 kHz signal with a peak voltage of 5.0 mV. The tuning
ir
uit

onsists of a 60 µH indu
tor in series with a variable
apa
itor. The indu
tor
oil has a resistan
e of
0.25 Ω, and the resistan
e of the rest of the
ir
uit is negligible.
(a) To what value should the
apa
itor be tuned to listen to this radio station? (Note that the

apa
itor needs to be tuned to where it is in resonan
e with the indu
tor).
(b) Cal
ulate the peak
urrent through the
ir
uit at resonan
e.
(
) A stronger station at 1050 kHz produ
es 10 mV antenna signal. Cal
ulate the
urrent at this
frequen
y and the
orresponding phase angle when the radio is tuned to 1000 kHz.

A at
oil of wire has an area A, N turns, and a resistan
e R. It is situated in a magneti
eld,
su
h that the normal to the
oil is parallel to the magneti
eld. The
oil is then rotated through
an angle of φ = 90◦
, so that the normal be
omes perpendi
ular to the magneti
eld. The
oil has
an area of 1.5 × 10−3 m2
, 50 turns, and a resistan
e of 140 Ω. During the time while it is rotating, a

harge of 8.5 × 10−5 C ows in the
oil. Cal
ulate the magnitude of the magneti
eld?

(a) Two parallel, very long wires 1 and 2 are separated by a distan
e of 0.065 m and
arry
urrents
of I1 = 15 A and I2 = 7 A. Find the magnitude of the for
e that the magneti
eld that wire 1
applies to a 1.5 m of wire 2 when the
urrents are in opposite dire
tion.
(b) A 150-turn solenoid
arries a
urrent of 12 A. The radius of the solenoid is 0.050 m; and its length
is 0.18 m. Determine the magneti
ux through the
ir
ular
ross-se
tional area at the
enter of
the solenoid.

The drawing below shows an ele
tri

ir
uit, where resistors are
onne
ted to a battery. If the
urrent
in the 8.0 Ω resistor is 0.5 A,
al
ulate:
(a) the equivalent resistan
e,
(b) the
urrent in ea
h resistor,
(
) the total
urrent owing in the
ir
uit,
(d) the voltage of the battery,
(e) the ele
tri
power of the
ir
uit.

We have an infinite, non conducting, sheet of negligible thicknress carrying a negative uniform surface charge density  and, next to it, an infinite parallel slab of thickness D with positive uniform volume charge density  (see sketch). All charges are fixed. Calculate the direction and the magnitude of the electric field.
(a) Above the negatively charged sheet.
(b) In the slab
(c) Below the slab
(d) Make a plot of E as a function of distance, z, from the sheet.

A charged sphere of mass 0.62 kg and net charge 0.34 µC hangs at rest at the end of an insulating string above a large sheet of charge. The horizontal sheet of uniform charge creates a uniform vertical electric field in the vicinity of the point charge. The tension in the string is measured to be 5.67 N.
(a) In a free-body diagram, show the forces that act on the charged sphere.
(b) Calculate the magnitude and direction of the electric field due to the sheet of charge.

Positive charge Q is distributed uniformly along the positive y-axis between y = 0 and y = a. A point P lies on the positive x-axis, a distance x from the origin (see figure)
(a) Calculate the x and y-components of the electric field produced by the charge distribution Q at points on the positive x-axis.
(b) Show that if x≫a
E_x ≅Q/(4πε_0 x^2 )
E_y ≅- Qa/(8πε_0 x^3 )
Explain why this result is obtained