Radioactivity is used in
A. flashlights
B. TV screens
C. fluorescent lights
D. smoke detectors
Answer: D. smoke detectors
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A fermion has integral spin
Indicate whether the statement is true or false
Which of the following best describes the greatest known value for index of refraction?
A. 1.732 B. 1.999.... (just shy of 2) C. 2.000... (2 exactly) D. a value greater than 2 but not greater than 3 E. a value greater than 3
Suppose it is late June. Based on the given right ascensions and declinations, which of the following stars crosses your meridian around midnight? Assume you live at a latitude where all the stars on this list rise above your horizon each day. (Hint: Recall that the Sun's celestial coordinates on the June solstice are RA = 6h, dec = +23-1/2°.)
A) Sirius: RA = 6hr 45m, dec = -16°42' B) Canopus: RA = 6hr 24m, dec = -52°41' C) Alpha Centauri: RA = 14hr 40m, dec = -60°50' D) Arcturus: RA = 14hr 16m, dec = +19°11' E) Vega: RA = 18hr 37m, dec = +38°47'
A battery is causing a large current in a solenoid (helical coil of wire). A bar magnet is held at rest nearby, aligned with the axis of the solenoid, with its south pole closest to the solenoid. The bar magnet is being repelled by the solenoid. Which of the following statements is true of the conventional current in the solenoid?
A. The current in the solenoid decreases B. The current in the solenoid is flowing clockwise as seen from the bar magnet C. The current in the solenoid is flowing counterclockwise as seen from the bar magnet D. The current in the solenoid increases E. The direction of the current in the solenoid alternates with a constant frequency