Question

A burst of green light (wavelength 550 nm) has a total energy of 5.50 ×10–17 J. How many photons does it contain? Report your answer with three significant figures. Do NOT include units in your answer. Use the format 2.22e2 or 2.22e-2 for scientific notation.

Answer 1

Answer:

152 photons

Step-by-step explanation:

Data provided in the question:

wavelength of the green light, λ = 550 nm = 550 × 10⁻⁹ m

Total energy = 5.50 × 10⁻¹⁷ J

Now,

Energy = $\frac{nhc}{\lambda}$

here,

n = number of photons

h = Plank's constant = 6.63 × 10⁻³⁴ J.s

c = speed of light = 3 × 10⁸ m/s

Therefore,

5.50 × 10⁻¹⁷ J =  $\frac{n\times(6.63\times10^{-34})\times(3\times10^8)}{550\times10^{-9}}$

or

( 5.50 × 10⁻¹⁷)( 550 × 10⁻⁹) = n(6.63 × 10⁻³⁴)(3 × 10⁸)

or

3025 × 10⁻²⁶ = n(19.89 × 10⁻²⁶ )

or

n = 152.086 ≈ 152 photons