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Exam 3
Discussion TA: _ _ _ _ _ _ _ _ _ _ _ _ __
1
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A conducting rod oflength t = 35.0 cm is free to slide on two parallel conducting bars as shown. Two resistors, RJ = 2.00 nand R2 = 5.00 n are connected across the ends ofthe bars to form a loop. A constant magnetic field B = 2.50 T is directed perpendicularly into the page. An external agent pulls the rod to the left with a constant speed of v = 8.00 mls . . (a)
(b)
(c)
[8 pts.) Find the currents in both resistors.
[6 pts.} Calculate the total power delivered to the resistance of the circuit.
[6 pts.} Find the magnitude ofthe applied force that is needed to move the rod with this constant velocity.
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Spi-ing 2013
.John HcFonJ
Nrune: ______________________________
Unid: __________________________
Discussion TA:
2
Exam 3
---------------------
Show all work!
[20 pIs.] A piece of copper wire with thin insulation, 200 m long and 1.00mm in diameter, is wound onto a plastic tube to
form a long solenoid. This coil has a circular cross section and consists of tightly wound turns in one layer. If the current
in the solenoid drops linearly from 1.80 A to zero in 0.120 seconds, an emf of 80.0 mV is induced in the coil. What is the
length ofthe solenoid, measured along its axis? Assume the radius of solenoid is much greater than 1.00 mm.
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.John DeFord
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Discussion TA:
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Exam 3
Unid: __________________ --------------
Show all work!
Consider a series RLC circuit having the following circuit parameters: R = 200 n, L = 663 mH, and C = 26.5 J.LF. The applied voltage has an amplitude of 50.0 V and a frequency of 60.0 Hz. (a)
(b)
(c)
(d) [5 pts.]
[5 pts.]
[5 pts.]
[5 pts.]
Find the current Imax, including its phase constant <II relative to the applied voltage b.v.
Find the voltage b.VR across the resistor and its phase relative the current.
Find the voltage b.Vc across the capacitor and its phase relative to the current.
Find the voltage b.VL across the inductor and its phase relative to the current. V->
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Exam 3
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Discussion TA: _ _ _ _ _ _ _ _ _ __
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An 80.0 n resistor, a 200 mH inductor, and a 0.1500 J.1.F' capacitor are connected in parallel across a 120 V (nns) source
operating at 374 radls.
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(a)
(b)
(c)
(d)
[5 pts.]
[6 pts.]
[5 pts.}
[4 pts.]
What is the resonant frequency of the circuit?
Calculate the nns current in the resistor, inductor and capacitor.
What is the nns current delivered by the source?
Is the current leading or lagging behind the voltage? By what angle?
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Ph~sics
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Sp.'ing 20L
Name: ____________________________
Vnid: ________________________
Discussion TA:
5
Exam 3
---------------
Show all work!
A microwave source produces pulses of 20.0 GHz radiation, with each pulse
lasting 1.00 ns. A parabolic reflector with a face area of radius ~ is
used to focus the microwaves into a parallel beam of radiation, as shown in
the drawing. The average power during each pulse is 25.0 kW.
(a) (b) (c) (d) (e) 12.0 em
[4 pIS.] What is the wavelength of these microwaves?
[4 pIS.} What is the total energy contained in each pulse?
[4 pIS.} Calculate the average energy density inside each pulse.
[4 pIS.} Determine the amplitude ofthe electric and magnetic fields in these microwaves.
[4 pIS.} Assuming this pulsed beam strikes an absorbing surface, calculate the force exerted on the surface during
the 1.00 ns duration of each pulse.
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