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bixtya [17]
3 years ago
9

Estimate the number of photons emitted per second from 1.0 cm2 of a person's skin if a typical emitted photon has a wavelength o

f 10,000 nm. Assume the skin of a person is at the normal body temperature of 37∘C.
Physics
1 answer:
Diano4ka-milaya [45]3 years ago
4 0

Answer:

2.63 x 10^18

Explanation:

A = 1 cm^2 = 1 x 10^-4 m^2

λ = 10,000 nm = 10,000 x 10^-9 m = 10^-5 m

T = 37 degree C = 37 + 273 = 310 k

Energy of each photon = h c / λ

where, h is the Plank's constant and c be the velocity of light

Energy of each photon = (6.63 x 10^-34 x 3 x 10^8) / 10^-5 = 1.989 x 10^-20 J

Energy radiated per unit time = σ A T^4

Where, σ is Stefan's constant

Energy radiated per unit time = 5.67 x 10^-8 x 10^-4 x 310^4 = 0.05236 J

Number of photons per second = Energy radiated per unit time / Energy of  

                                                                                               each photon

Number of photons per second = 0.05236 / (1.989 x 10^-20) = 2.63 x 10^18

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Answer:

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two wires have the same length, but the second has twice the diameter of the first. find the resistance of the second wire if th
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1 year ago
Calculate the amount of energy transferred when a 40w light bulb is left on for 30 minutes.
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E=72000J or 72kj

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3 years ago
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Calculate the binding energy e of the boron nucleus 11 5b (1ev=1.602×10−19j). express your answer in millions of electron volts
nignag [31]
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