I am doing a practice exam with 20 questions and i am stuck on 2 of them. The answer were given by the professor but i am not sure how to get them. both of the questions are from interference and diffraction.
1) you dip a wire loop in to soapy water (n=1.33) and hold it up vertically to look at the soap film in white light. The soap film looks dark at the top because it has sagged, and its thickness there is nearly zero, causing the reflected wavelengths to interfere destructively. Part way down the loop you see the first read band of the reflected white light. What is the thickness of the soap film there? (take the red light to be 680nm)
answer= 170 nm
2)The pupil of the human eye has a diameter of about 5mm. When the wavelength of light incident on the pupil is 500nm, the smallest angular separation of two resolveable sources is approximately ?
answer = 1'
thanks in advance 🙂
1) you dip a wire loop in to soapy water (n=1.33) and hold it up vertically to look at the soap film in white light. The soap film looks dark at the top because it has sagged, and its thickness there is nearly zero, causing the reflected wavelengths to interfere destructively. Part way down the loop you see the first read band of the reflected white light. What is the thickness of the soap film there? (take the red light to be 680nm)
answer= 170 nm
2)The pupil of the human eye has a diameter of about 5mm. When the wavelength of light incident on the pupil is 500nm, the smallest angular separation of two resolveable sources is approximately ?
answer = 1'
thanks in advance 🙂
