1.) A laser emits light of frequency 3.72 x 1014 /s. What is the wavelength of the light in m? 2.) Calculate the energy, in joules, of a single photon associated with frequency of 4.00x105/s

3.) Determine the frequency and energy of a photon whose wavelength is 2.57x10-7 m

explanation and work needed please

1. λ = 806nm

2. E = 2.6504 × 10^-28J

3. a) f = 1.167 × 10^15 Hz

b) E = 7.73 × 10^-19J

Explanation:

1) The wavelength denoted by λ can be calculated using the formula:

λ = v / f

Where;

v = speed of light (3×10^8m/s)

f = frequency of light (Hz)

λ = 3 × 10^8/3.72 x 1014

λ = 0.80645 × 10^(8-14)

λ = 0.80645 × 10^-6

λ = 8.06 × 10^-7m

λ = 806nm

2) The energy (J) of a photon is calculated thus;

E = hf

Where;

h = Planck's constant (6.626 × 10^-34J/s)

f = frequency (4.00x10^5/s)

E = 6.626 × 10^-34 × 4.00x10^5

E = 26.504 × 10^(-34+5)

E = 26.504 × 10^-29

E = 2.6504 × 10^-28J

3. λ = v / f

2.57x10^-7 = 3 × 10^8 ÷ f

f = 3 × 10^8/2.57x10^-7

f = 1.167 × 10^(8+7)

f = 1.167 × 10^15 Hz

b) E = hf

E = 6.626 × 10^-34 × 1.167 × 10^15

E = 7.7325 × 10^(-34+15)

E = 7.73 × 10^-19J

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.  

the answer to your question is c