The old style (incandescent) light bulb converts more energy
into heat than it does into light. If you're using it mainly as a
source of light, then it's a bummer, and its efficiency is very low.
BUT ... if you're using an incandescent light bulb as a heater, then
its efficiency is much better. It all depends on your point of view.
Answer: 117.8 nm
Explanation:
Given,
Nonreflective coating refractive index : n = 1.21
Index of refraction:
= 1.52
Wave length of light = λ = 570 nm = 


Hence, the minimum thickness of the coating that will accomplish= 117.8 nm
Answer:
The answer is number 2 :)
Answer:

Explanation:
P = Power = 50 kW
n = Number of photons per second
h = Planck's constant = 
= Frequency = 781 kHz
r = Distance at which the photon intensity is i = 1 photon/m²
Power is given by

Photon intensity is given by

The distance is 