**Unformatted text preview: **PHY2054 FINAL EXAM MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) A 2.0 11F capacitor is charged until it acquires a potential difference of 500.0 V across its plates, then
the emf source is removed. If the capacitor is then discharged through a 100.0 kn resistance of a circuit (starting at t=0), what is the time when the voltage drop across the capacit is 200V?
A) 0.52 s B) 0.36 s C) 0.10 s ‘8 s 2) A cylindrical wire has a resistance R and resistivity p. If its length and diameter are both cut in half,
its resistivity will now be:
A) 4p B) p/4 C) 9/2 D) 2p E) p 3) Ions having equal charges but masses of M and 2M are accelerated through the same potential
difference and then enter a uniform magnetic field perpendicular to their path. If the heavier ions
folio circular arc of radius R, the radius of the arc followed by the lighter ions will be: @ B) 3R C) R/2 D) 4R E) 45 R 4) A. series R-L DC circuit has a 60 V battery, a 36 H inductor, a 21 ohm resistor, and a switch S.
Initially, the switch is open. At time t = 0 s, the switch is closed.When the resistor voltage is equal to the inductor voltage, the u nt in the circuit is closest to:
A) 1.7 A C) 1.1 A D) 0.86 A E) 0.57 A 5) A series RLC circuit has a peak voltage of 108 V and a peak current of 1.00 A. If the current lags the
voltage by 70.0°, what is the average power of the circuit?
A)36W B)148W C)296W @I 6) An RLC circuit has a resistance of 5.0 K), a capacitance of 16.0 11F, and an inductance of 54.0 H. If
the frequency of the alternating current is 2.0/7t kHz, what is the phase shift between the current and the total voltage? .
A) 3.1 rad B) 43 rad @ rad D) 1.8 rad -> -)
7) At a certain instant in time, an electromagnetic wave has E in the -z direction and B in the
+y direction. in what direction does the wave propagate?
A) +y direction B -2 direction
@ direction
+2 direction E) —x direction 8) A ray in air is incident on a glass plate whose index of refraction is 1.56. The angle of refraction is
one half the angle of reﬂection. The angle of - - . -'on is closest to:
A) 37° B) 35° ® D) 31° E) 33° 9) The speed of light in a material is 0.51 c. What is the critical angle of a light ray at the interface betw - n the material and a vacuum?
B) 25° C) 21° D) 28° 1) 2) 3) 4) 5) 6) 8) 9) 10) An object 3.4 mm tall is placed 25 cm from the vertex of a convex spherical mirror. The radius of 10)
curvature of the mirror has magnitude 73 cm. How far is the image from the vertex of the mirror? A)20cm B)50cm D)79cm E)25cm Regular problems (10 points each) 11) As part of a piece of optical apparatus to be used in air, you need to design a thin lens
having faces with radii of curvature of magnitude 24.0 cm each. When an object 32.0 mm
tall is placed 30.0 cm from this lens, it must form a real image 60.0 cm from the lens. (a)
What should be the shape of the lens and the index of refraction of the lens material? (b)
What is the height of the image of the object? Is it erect or inverted? .. /: (A7 F” “ﬁt-ﬁler!“ YeJa‘mn/e—93/PO M g-o.3m’ S 0-6M
EL’l’sL’ 23"- —’71£=0-2 M, {70' oomvcvy-‘y lens, we K 14w shy/e is double. WV”. TIMI. R,:a.>‘1‘r'l, R,:—o.z4I-M OZ
3Lzm—n(-,é~,—$L) Mare-kn n:/.6’ 12) What is the current through resistor R1 in the circuit in Figure 1? £|ZlKVb 2;:7lv/ Figurel
Jmu/ﬁxh mitt R1100!) 12215.00
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