A star is observed with a surface temperature of 3,000 K and a luminosity of 10?2 solar. What is the approximate radius of this star?
A) 1 solar radius B) 0.3 solar radius
C) 0.1 solar radius D) The radius cannot be determined.
B
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Which of the following correctly lists the various parts of the electromagnetic spectrum in the correct order from lowest to highest energy.
A. infrared, ultraviolet, radio waves, gamma rays, visible B. gamma rays, infrared, ultraviolet, radio waves, visible C. radio waves, ultraviolet, visible, infrared, gamma rays D. gamma rays, ultraviolet, visible, infrared, radio waves E. radio waves, infrared, visible, ultraviolet, gamma rays
White light is spread out into spectral hues by a diffraction grating. If the grating has 1000 lines per cm, at what angle will red light (? = 640 nm) appear in first order?
A. 14.7° B. 7.35° C. 17.7° D. 3.67° E. 1.84°
The focal length of a thin lens is 40 mm and its aperture diameter is 10 mm. What is the f-number of this lens?
A) f/4.0 B) f/2.0 C) f/5.6 D) f/0.30 E) f/0.40
Explain why a heating system made by circulating hot water through a concrete floor could be desirable. Would it be better to circulate the hot water through the ceiling? Why or why not?
What will be an ideal response?