Photon Energy: The human eye can just detect green light of wavelength 500 nm if it arrives at the retina at the rate of 2 × 10-18 W. How many photons arrive each second? (c = 3.0 × 108 m/s, h = 6.626 × 10-34 J ? s)
Fill in the blank(s) with the appropriate word(s).
Answer: 5
You might also like to view...
Entropy: On a cold winter day, the outside temperature is -20°C and the inside temperature is maintained at 20°C. There is a net heat flow to the outside through the walls, roof, etc., of 25 kW. At what rate is the entropy of the air outside the house changing as a result of this process?
A. +13 W/K B. -25 W/K C. 85 W/K D. +99 W/K E. 0 W/K
From the beginnings of life on Earth, it took less than a billion years for single-celled organisms to evolve to multicellular organisms
Indicate whether the statement is true or false
A 5-g coin is dropped from a 300-m building. If it reaches a terminal velocity of 45 m/s, and the rest of the energy is converted to heating the coin, what is the change in temperature (in °C) of the coin? (The specific heat of copper is 387 J/kg/°C.)
a. 9 b. 2 c. 5 d. 21 e. 0.5
An electromagnetic wave with components Ey = Eo sin(kx - ?t) and Bz = Bo sin(kx - ?t) is a wave traveling in the
A) negative x-direction. B) x-direction. C) y-direction. D) z-direction. E) cannot be determined with the information given