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)
5
You might also like to view...
If the radiant energy from the Sun comes in as a plane EM wave of intensity 1 340 W/m2, calculate the peak values of E and B. (µ0 = 4? × 10^?7 T?m/A, c = 3.00×108 m/s)
a. 330 V/m, 3.00 × 10^?4 T b. 1 010 V/m, 3.35 × 10^?6 T c. 330 V/m, 3.35 × 10^?6 T d. 1 010 V/m, 3.00 × 10^?4 T
Each of two vectors, 
and 
, lies along a coordinate axis in the xy plane. Each vector has its tail at the origin, and the dot product of the two vectors is 
data-wiris-created="true" class="Wirisformula" />. Which possibility is correct? A.
and both lie along the positive x axis.B.
lies along the positive x axis. lies along the negative x axis.C.
and both lie along the positive y axis.D.
lies along the negative x axis. lies along the negative y axis.E.
lies along the positive y axis. lies along the negative y axis.An ice skater performs a pirouette (a fast spin) by pulling in his outstretched arms close to his body. What happens to his rotational kinetic energy about the axis of rotation?
A) It changes, but it is impossible to tell which way. B) It increases. C) It does not change. D) It decreases.
A bullet is fired with a certain velocity at an angle ? above the horizontal at a location where g = 10.0 m/s2. The initial x and y components of its velocity are 86.6 m/s and 50.0 m/s respectively
How long does it take before the bullet gets to the highest point of its trajectory? A) 5.0 seconds B) 10.0 seconds C) 15.0 seconds D) 20.0 seconds E) None of the other choices is correct.