This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: Problems: Week 8 8—1. 8—3. The curves show the paths (in xy—plane) of three particles in the presence of a constant 5
ﬁeld B = ~32 ' what can you say about the charge carried by each palticle? Why?‘ What is the force experienced by a conductor aligned along the z—axis if it carries a
current of lOamps and is located in a g = —0.1Tz“ ﬁeld? Why? A cyclotron has an oscillator frequency of 12MHZ and a DEE radius of 53cm. What
value of 5 would you need to accelerate deuterons (positive chargel .6 ><10"19 C). 8—4. 8—5. 8—6. In a constant L3 ﬁeld a charge with velocity Z J. E has a circular path of radius r = qB
(i) If 13  2 what is the plane of the path. (ii) If you double V what happens to the
angular velocity of the charge? Why? A proton travelling at 105 m/ s )2 is introduced between two parallel plates which have
an E =100N/C 3”). What L3 ﬁeld would you apply so that the proton goes through un— deﬂected? [This is the principle of the velocity selector]. 10:. ii A S—turn coil of radius 50cm is lying ﬂat in the xzplane. If it carries a current of lOamps
ﬂowing counter clockwise, what is the magnetic moment (magnitude and direction). ' Y 87. 88. 89. If you apply a E ﬁeld of 0.1T, at an angle of 30° with respect to the y—axis, to the coil of
problem 86, what is the torque (magnitude and direction) on the coil? The Biot—Savart law tells us that a current I ﬂowing through a conducting wire of length M , produces a 13 ~ﬁeld at Eu M) given by M .A_B. = ~”—°J * Z“:
47: r Show that the E ~ﬁeld lines circulate around the current. Since the 13 —ﬁeld due to a current swirls around it (like water circulates as it ﬂows out of
a bath tub) Ampere taught us that the circulation of the 13 —ﬁeld around a closed loop
2 B  AZ C—._. is determined solely by the currents ﬂowing through the surface on which the loop is '
drawn. That is,
EC§~A£ = #021,. —> where {no is a fundamental constant _ T~m
,uo =47r><10 7T Supposing we have a single current I ﬂowing along the y—axis. Please use ampere’s law
and the symmetry of the problem to show that the. Q ﬁeld at a point P in the xz— plane is
given by #0] n B A :—
_.(I) 27” where r is distance‘between P and the y~axis? 8—10. A tightly wound long solenoid consists of a large number of closely spaced rings with a '8211. common axis (see ﬁgure). It produces a uniform ﬁeld inside it. Use Ampere’s law to
ShOW that for the case shown (cow current in Solenoid) ' ' Q : —,Lt0nb"c ‘ '
where a: No. of turns/meter of thesolenoid. (n=‘N/L) .M _ Ifr‘
l IKEl I r‘f/I
wind 7 "‘ ' ’ "V In a mass spectrometer, the beam at 0 consists of two kinds of particles with same mass
(M) but different charges (1;, q; entering with a velocity v = V)“; . For E = ~Bz” and the paths shown, what is the sign of the charge (+ive or ~ive)? Where will the larger charge
land, P l or P2? Justify your answer. 8—12. Why do two parallel currents attract one another? 8—13. Shown is a coil of width b and length 16’ Suspended vertically in a 5 ﬁeld. How would you make it work like a motor? The coil is free to rotate about its vertical axis. 8—14. A coil of crosssection {:1 : (2 x 3)m2ﬁ is being rotated about the vertical in the presence of a constant 5 : 0,2Tz . What is the maximum and minimum ﬂux of g through the
coil? Why? 815. Imagine that a cube of side 1m is located at a height of mm above the Earth’s surface. I If.
the ﬂux of E through 3 of the faces is 90yT — 1112 what must be the ﬂux through the other three? Why? 8—16. Write an essay on
~ “What is a Bar Magnet” I
Starting from the idea that a single electron is a “bar magnet” of magnetic moment 9.27x10”24A ~m2. 817. Why does a bar magnet attract a piece of iron? ...
View
Full Document
 Fall '11
 Bhagat
 Physics, Magnetism, Magnetic Field, Electric charge, Magnetic moment, Ampere, bar magnet

Click to edit the document details