f09ex2

# F09ex2

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Unformatted text preview: rth pole of a compass needle would point. (2 pts) I 8. A current loop (viewed edge ­on) in a magnetic field is experiencing a CCW torque, as shown. Indicate on the diagram the direction of the current in the loop. (2 pts) Name__________________________________ (9 ­10) Positive ions of traveling to the right enter a region of uniform magnetic field directed perpendicular to the page. They all have the same speed, but they have various masses. 9. (2 pts) The magnetic field is directed a. to the right b. to the left c. up d. down e. out of the page f. into the page 10. (2 pts) Which path do the positive ions of greatest mass follow? (circle one.) 11. (2 pts) A conducting bar is moved upward in a uniform magnetic field directed into the page as shown. Positively charged particles in the bar experience a magnetic force a. to the right b. to the left c. up d. down e. out of the page f. into the page 12. A conducting loop (viewed edge ­on) is held near a bar magnet as shown. The magnet is then moved toward the loop as shown. While the magnet is moving towards the loop, does the loop exert a force on the magnet? Explain your reasoning in detail. (4 pts) N S Name__________________________________ 13. A particular blue whale call has a frequency of 15 Hertz (Hz). What’s the wavelength of this call? The speed of sound in sea water is about 1500 m/s. (3 pts) 14. Determine the following properties of the wave represented in the graph at right. Or, if it’s impossible to determine with the given information, say so. a. amplitude (1 pt) b. wavelength (2 pts) c. period (2 pts) d. frequency (2 pts) 15. The diagram shows a history graph of a wave. (I’ve left the axes unlabeled.) On the same axes, sketch another wave traveling in the same medium that has a higher frequency. (2 pts) 16. The intensity level of sound that has an intensity of 10 ­6 W/m2 is 60 dB. What’s the intensity level of sound that has an intensity of 10 ­5 W/m2? (2 pts) 17. (2 pts) The intensity at a distance of 1.0 m from a speaker is 10 W/m2. At a distance of 10 m from the speaker, the intensity would be (assuming the speaker emits sound equally in all directions) a. 100 W/m2 b. 10 W/m2 c. 1.0 W/m2 d. 0.10 W/m2 Name__________________________________ 18. (2 pts) Beats occur when two waves are of a. slightly different frequencies b. slightly different amplitudes c. slightly different speed d. opposite displacement 19. The figure at right represents a standing wave in a stretched string. The speed of waves on the string is 450 m/s, and the length of the string is 3.0 m. a. Determine the frequency of this standing wave. (3 pts) tring? b. What’s the fundamental frequency of this string? (2 pts) ulate its wavelength . Recall that the guitar string is 60 long. 20. A tube is open at one end and closed at the other. How exactly would opening the closed end of the tube change the lowest possible frequency of standing waves in the tube? Explain, with the aid of appropriate diagrams. (3 pts) e wavelength of the fundamental is always given by for a string that is held ﬁxed at b...
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## This note was uploaded on 09/15/2013 for the course PHYS 112 taught by Professor Cui during the Fall '08 term at UMBC.

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