Light of wavelength 600 nm in vacuum is incident nearly perpendicularly on a thin film whose index of refraction is 1.5. the light travels from the top surface of the film to the bottom surface, reflects from the bottom surface, and returns to the top surface, as the drawing indicates. what is the total (down-and-back) distance traveled by the light inside the film? express your answer in terms of the wavelength λfilm of the light within the film.

6λ_film

Explanation:

Light of wavelength λ 600 nm

Assuming length of thin film of water to be 1200 nm

Total distance traveled = 2×1200 ×10^{-9} = m

Now, Wavelength of light in film = λ/n

n= refractive index

= = 4×10^{-7}

No. of wavelengths = distance traveled/Wavelength of light in film

= = 6

therefore,  the total (down-and-back) distance traveled by the light inside the film in terms of wavelength λfilm = 6λfilm

5 w for 1hr = 5x60x60 joules=300x60=3000x6=18,000j as total energy conversion. efficiency of bulb needed for radiant to thermal within 18000

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min