Why do sunspots appear dark?
A) They are composed of different elements than the rest of the sun.
B) They are regions that do not emit any radiation.
C) They are regions that are significantly cooler than the rest of the photosphere.
D) They are regions nearly devoid of gas.
C) They are regions that are significantly cooler than the rest of the photosphere.
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Strictly speaking, it is correct to say that voltage
A) flows through a circuit. B) flows across a circuit. C) is impressed across a device in a circuit. D) all of these
What is the resolving power of a diffraction grating that is capable of just distinguishing between two wavelengths of 568.20 nm and 569.60 nm? (1 nm = 10?9 m)
a. 1.10 b. 406 c. 487 d. 812 e. 568.9
The electric field in the region defined by the y-z plane and the positive x axis is given by E = ax, where a is a constant. (There is no field for negative values of x.) As x increases in magnitude, relative to V = 0 at the origin, the electric potential in the region defined above is
a. a decreasing function proportional to ?|x2|. b. a decreasing function proportional to ?|x|. c. constant. d. an increasing function proportional to +|x|. e. an increasing function proportional to +|x2|.
Light of wavelength 500 nm illuminates a round 0.50-mm-diameter hole. A screen is placed 6.0 m past the slit. What is the width of the central bright circle on the screen?
A) 3700 ?m B) 7.3 mm C) 15 mm D) 260 ?m