Answer:
All forces are either balanced or unbalanced and each force acts in different ways.
The answer is B.
t = Vy / g
t =( 19 x sin21 ) / 9.8 = 0.69s
Answer
given,
the volume of eye
![V = \dfrac{4}{3}\pi r^3](https://tex.z-dn.net/?f=V%20%3D%20%5Cdfrac%7B4%7D%7B3%7D%5Cpi%20r%5E3)
![V = \dfrac{4}{3}\pi 1.5^3\times 10^{-6}](https://tex.z-dn.net/?f=V%20%3D%20%5Cdfrac%7B4%7D%7B3%7D%5Cpi%201.5%5E3%5Ctimes%2010%5E%7B-6%7D)
![V =4.5 \times 10^{-6}](https://tex.z-dn.net/?f=V%20%3D4.5%20%5Ctimes%2010%5E%7B-6%7D)
temperature 37 = 273 + 37 = 310 K
Radiation energy density
![u = aT^4](https://tex.z-dn.net/?f=u%20%3D%20aT%5E4)
![u = \dfrac{4\sigma }{cT^4}](https://tex.z-dn.net/?f=u%20%3D%20%5Cdfrac%7B4%5Csigma%20%7D%7BcT%5E4%7D)
energy of the BB photons
![E = \dfrac{\sigma }{cT^4V}](https://tex.z-dn.net/?f=E%20%3D%20%5Cdfrac%7B%5Csigma%20%7D%7BcT%5E4V%7D)
![E = 9.9 \times 10^{-11}\ J](https://tex.z-dn.net/?f=E%20%3D%209.9%20%5Ctimes%2010%5E%7B-11%7D%5C%20J)
Flux from the lamp
![F = \dfrac{100}{4\pi \times \pi \times (0.1 \times 10^{-2})^2}](https://tex.z-dn.net/?f=F%20%3D%20%5Cdfrac%7B100%7D%7B4%5Cpi%20%5Ctimes%20%5Cpi%20%5Ctimes%20%280.1%20%5Ctimes%2010%5E%7B-2%7D%29%5E2%7D)
![F = 2.5 \times 10^{-5} J/s](https://tex.z-dn.net/?f=F%20%3D%202.5%20%5Ctimes%2010%5E%7B-5%7D%20J%2Fs)
Full energy of lamp
![N = \dfrac{F\times 2 R_{eye}}{c}](https://tex.z-dn.net/?f=N%20%3D%20%5Cdfrac%7BF%5Ctimes%202%20R_%7Beye%7D%7D%7Bc%7D)
![N = \dfrac{2.5 \times 10^{-5}\times 0.03}{3\times 10^{10}}](https://tex.z-dn.net/?f=N%20%3D%20%5Cdfrac%7B2.5%20%5Ctimes%2010%5E%7B-5%7D%5Ctimes%200.03%7D%7B3%5Ctimes%2010%5E%7B10%7D%7D)
![N = 2.5 \times 10^{-15} J](https://tex.z-dn.net/?f=N%20%3D%202.5%20%5Ctimes%2010%5E%7B-15%7D%20J)
when we close your eyes the light from the source stop and the black body photon starts hitting retina which will cause darkness.