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1 Name: Date: Final Exam Physics 2306 Fall 2012 FORM A BEFORE YOU BEGIN: 1. Fill in CORRECTLY your ID number in the Scantron, as well as which FORM of the test you have. 2. Write in the course number (2306) 3. Write down your name on the test and scantron; fill in the appropriate bubbles 4. Assume MKS units unless specified otherwise. 5. Use these values: v sound in air = 343 m/s g = 9.8 m/s 2 e=1.6x10-19 C k=9.0x10 9 Nm 2 /C 2 0 = 8.85 x C 2 /(Nm 2 ) µ 0 = 4 x 10-7 Tm/A c = 3.0 x 10 8 m/s For problems where you are asked to rank items, items of different magnitudes should be separated by commas, while those of the same magnitude should have no comma between them. For example: Rank the following numbers from highest to lowest A) 7 B) 5 C) 5 D) 3 Answer: A,BC,D Honor Code I have neither given nor received unauthorized assistance on this assignment. (sign here)

2 1 A ray of light passes from air (index of refraction n=1) through a glass prism (index of refraction n=1.6). The prism has a cross section that is an equilateral triangle (see figure). What is the angle? (Hint: note the symmetry and the 30 angle relative to the surface normal.) 1) 79 o 2) 53 o 3) 15 o 4) 30 o 5) 23 o 2 An ant 5 mm tall is located 5.0 cm away from a converging lens. The lens has a focal length of 6.0 cm. What is the image size of the ant seen through the lens? (The ant, lens, and observer are all aligned.) 1) 1.0 cm 2) 2.0 cm 3) 3.0 cm 4) 4.0 cm 5) 5.0 cm 6) 6.0 cm 7) none of the above

3 3 A conducting sphere with radius is centered within another large conducting sphere with radius >> a, and the volume between them is filled with a material having resistivity. Find the resistance between the two spheres. 1) 2) Hint: Consider the resistance of concentric spherical shells (whose resistance is proportional to, its thickness dr, and inversely proportional to its area), and integrate to find the total resistance. 3) 4 4) 5) 6) none of the above 4 Calculate the equivalent resistance across the battery for the following circuit. 1) 3.3 2) 12 3) 5.6 4) 1.3 5) 6.4

If this current is made up of positive charges flowing from left to right, the potential difference V B V A is.

4 5 A positive current flows from left to right through a conducting rectangle immersed into a magnetic field pointing upwards as shown. A voltage (called the Hall effect) is developed across the conductor as shown. If this current is made up of negative charges flowing from right to left, the potential difference V B V A is. If this current is made up of positive charges flowing from left to right, the potential difference V B V A is. 1) negative (positive) 2) positive (negative) 3) positive (positive) 4) negative (negative) 5) can not tell V B V A 6 A hollow conducting spherical shell has inner radius 0.80 m and outer radius 1.20 m, as shown in the figure. The sphere carries an excess charge of -500 nc. A point charge of +300 nc is present at the center. The surface charge density on the outer spherical surface is 1) 21 nc/m 2 2) 15 nc/m 2 3) 11 nc/m 2 4) 18 nc/m 2 5) 0 C/m 2

5 7 Three point charges of μc, μc, and μc are placed along the x-axis as shown in the figure. What is the electrical potential at point P (relative to zero at infinity) due to these charges? 1) +154 kv 2) 154 kv 3) 307 kv 4) 0 kv 5) +307 kv 8 Four capacitors are connected across a 90-V voltage source as shown in the figure. What is the voltage across the 4.0 capacitor. 1) 60 V 2) 90 V 3) 50 V 4) 30 V 5) 40 V

6 9 An electromagnetic wave propagates along the +y-direction as shown in the figure. If at one moment the electric field at the origin is along the +z-direction, what is the direction of the magnetic field at that moment? 1) +y 2) x 3) z 4) +x 5) +z 10 If the average intensity of an electromagnetic wave is 8.0 x 10 7 W/m 2, what is the amplitude of the magnetic field of this wave? 1) 8.2 X 10 4 T 2) 1.2 X 10 9 T 3) 6.2 X 10 6 T 4) 7.2 X 10 1 T 5) 9.4 X 10 2 T

7 11 A 360-nm thick oil film floats on the surface of water. The indices of refraction of the oil and the water are 1.50 and 1.33, respectively. The surface of the oil is illuminated from above at normal incidence with white light. What TWO wavelengths of light in the 400-nm to 800-nm wavelength band are most strongly reflected? 1) 470 nm and 760 nm 2) 410 nm and 700 nm 3) 450 nm and 740 nm 4) 490 nm and 780 nm 5) 430 nm and 720 nm 12 Light of wavelength 687 nm is incident on a single slit 0.75 mm wide. At what distance from the slit should a screen be placed if the first dark fringe in the diffraction pattern is to be 1.7 mm from the center of the diffraction pattern? 1) 1.1 m 2) 1.9 m 3) 0.93 m 4) 0.39 m 5) 0.47 m

8 13 The figure shows the cross-section of a hollow cylinder of inner radius a = 5.0 cm and outer radius b = 7.0 cm. A uniform current density of 1.0 A/ cm 2 flows through the cylinder parallel to its axis. Calculate the magnitude of the magnetic field at a distance of d = 10 cm from the axis of the cylinder. (μ 0 = 4π 10-7 T m/a) 1) 0.00 T 2) 1.5 x 10-4 T 3) 0.50 x 10-4 T 4) 2.5 x 10-4 T 5) 4.5 x 10-4 T 14 The three loops of wire shown in the figure are all subject to the same uniform magnetic field that does not vary with time. Loop 1 oscillates back and forth as the bob in a pendulum, loop 2 rotates about a vertical axis, and loop 3 oscillates up and down at the end of a spring. Which loop, or loops, will have an emf induced in them? 1) Loop 2 only 2) Loops 1 and 2 3) Loops 2 and 3 4) Loop 1 only 5) Loop 3 only

9 15 An inductor has a current: cos 3.77 flowing through it. If the maximum emf across the inductor is equal to V, what is the self-inductance of the inductor? 1) 4.61 mh 2) 2.63 mh 3) 1.98 mh 4) 3.29 mh 5) 3.95 mh 16 A long (massive) rope is hung from the ceiling. You send a sinusoidal wave up it from the bottom. As the wave progresses upwards, its speed, its wavelength and its frequency. 1) decreases,increases, remains constant 2) increases, decreases, remains constant 3) increases, increases, remains constant 4) remains constant, decreases, increases 5) increases, increases, increases

10 17 I stand some distance from an isotropic sound source, and then walk 10 meters further away from the source. If the intensity falls by a factor of 16, how far am I now from the source? 1) 10m 2) 10.63m 3) 10.67m 4) 12.5m 5) 13.3m 6) 20m 7) none of the above 18 A guitar string one meter long has a mass density of 0.70 g/m is tensioned such that when played in its fundamental mode, a listener hears a sound with a wavelength of 1.0 m. What is the string s tension? (Hint: this is a multi-step problem.) The speed of sound in air is 343 m/s. 1) 329 N 2) 115 N 3) 423 N 4) 542 N 5) none of the above

11 19 An LR series circuit is driven at a frequency of 60 Hz. The inductor is 2.0 mh and the resistor is 300 Ohms. What is the phase angle between the current and voltage provided by the AC source? 1) 1.25 mradians 2) 2.5 mradians 3) 3.5 mradians 4) 5.5 mradians 5) none of the above 20 A series R-L-C circuit is driven by an AC voltage source of amplitude 75.0V and angular frequency 4000 rad/s. The capacitor is 12.5 F, the inductor is 5.00 mh, and the resistor is What is the amplitude of the current? 1) 1.10 A 2) 2.14 A 3) 3.26 A 4) 4.48 A 5) 5.61 A

PHY2054 Summer 2017 Final ExamVersion 2

PHY2054 Summer 2017 Final ExamVersion 2 MULTIPLE CHOICE. Please answer all questions by choosing the one alternative that best completes the statement or answers the question. 1) When two or more capacitors