The present standard for time is based on
a. the transition of an electron between two energy levels of the cesium-133 atom.
b. Earth's rotation.
c. Earth's orbit.
d. none of these.
a
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What happens to centripetal force when speed decreases, in the special case that the object continues moving in a circle of the same radius?
a. The force also decreases. b. The force increases. c. The radius cannot stay the same. d. The force sometimes stays the same and sometimes decreases. e. Speed does not affect centripetal force.
In which direction should the electrode tabs point for a 12-lead ECG?
You are holding on to one end of a long string that is fastened to a rigid steel light pole. After producing a wave pulse that was 5 mm high and 4 cm wide, you want to produce a pulse that is 6 cm wide but still 5 mm high. You must move your hand up and down once,
A. the same distance up as before, but take a shorter time. B. the same distance up as before, but take a longer time. C. a smaller distance up, but take a shorter time. D. a greater distance up, but take a longer time. E. a greater distance up, but take the same time.
A diffraction grating has 6000. lines per centimeter ruled on it. What is the angular separation between the second and the third orders on the same side of the central order when the grating is illuminated with a beam of light of wavelength 550
nm?