Camera Optics: The focal length of the lens of a simple digital camera is 40 mm, and it is originally focused on a person 25 m away. In what direction must the lens be moved to change the focus of the camera to a person 4.0 m away?
A. It does not make any difference.
B. sideways from the CCD sensors
C. away from the CCD sensors
D. towards the CCD sensors
Answer: C
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Energy and Mass: A person with an initial mass of 70 kg climbs a stairway and thereby rises 6.0 m in elevation. By how much does his mass increase by virtue of his increased potential energy? (c = 3.0 × 108 m/s)
Fill in the blank(s) with the appropriate word(s).
A positively charged insulating rod is brought close to an object that is suspended by a string. If the object is repelled away from the rod we can conclude:
A) the object is positively charged B) the object is negatively charged C) the object is an insulator D) the object is a conductor E) none of the above
Two electrons, "A" and "B," traverse the same region of a bubble chamber. Which of the following would cause electron B's path to curve more strongly than electron A's path?
A) Electron B is moving slower. B) Electron B has a larger mass. C) Electron B has a bad cold. D) Electron B is moving faster. E) Electron B has a larger charge.
A series LRC circuit consists of a 12.0-mH inductor, a 15.0-µF capacitor, a resistor, and a 110-V (rms) ac voltage source
If the impedance of this circuit is 45.0 ? at resonance, what is its impedance at a frequency twice the resonance frequency?