Answer:
4.2 x 10²⁷ photons
Explanation:
Remember that the energy of a single photon is given by
E = hc/λ where λ is the wavelength, c speed of light, and h Planck's constant.
So to solve the problem we need to calculate the energy in joules necessary to heat the water and then divide by the enegy above for a photon.
Ephoton= 6.626 x 10 ⁻³⁴ Js x 3 x 10^8 m/s / 1.55 x 10⁻² m
= 1.28 x 10⁻²³ J/photon
ΔHs= m x C x ΔT
T₁ = 20.0 + 273 = 293 K
T₂= 98.0 + 273 = 371 K
C= 4.184 J/ g K ( Specific Heat of water )
ΔHs= 167 g x 4.184 j/gK x ( 371 - 293 ) K = 5.45 x 10⁴ J
# photons = 5.45 x 10⁴ J/ 1.28 x 10⁻²³ J/photon = 4.2 x 10 ²⁷ photons
