Multiple-Choice Questions Animals Vision and Diffraction Multiple-Choice Questions Physics and Astronomy Outreach Program at the University of British Columbia

Question 1 As two points on a piece of paper are moved Vision and Diffraction Question 1 As two points on a piece of paper are moved towards you how does the angle the points make with respect to your eye change? a) No change Smaller c) Larger Physics and Astronomy Outreach Program at the University of British Columbia 2

Question 1 Solution As two points on a piece of paper are moved Vision and Diffraction Question 1 Solution As two points on a piece of paper are moved towards you how does the angle the points make with respect to your eye change? a) No change Smaller c) Larger Physics and Astronomy Outreach Program at the University of British Columbia 3

Question 2 How does the width (W) of the central maximum Vision and Diffraction Question 2 How does the width (W) of the central maximum formed from diffraction through a circular aperture (pupil) change with aperture size (D) for a fixed distance away from the aperture? a) W increases as D increases b) W decreases as D increases c) W does not depend on D Physics and Astronomy Outreach Program at the University of British Columbia 4

Question 2 Solution a) W increases as D increases Vision and Diffraction Question 2 Solution How does the width (W) of the central maximum formed from diffraction through a circular aperture (pupil) change with aperture size (D) for a fixed distance away from the aperture? Point source D θ1 a) W increases as D increases b) W decreases as D increases c) W does not depend on D θ1=1.22 λ/D As D increases θ1 decreases Physics and Astronomy Outreach Program at the University of British Columbia 5

Question 3 Would you be able to resolve two points on a Vision and Diffraction Question 3 Would you be able to resolve two points on a piece of paper from further away with a smaller or larger pupil? a) Smaller b) Larger c) Pupil size doesn’t matter Physics and Astronomy Outreach Program at the University of British Columbia

Question 3 Solution b) Larger θ1=1.22λ/D Vision and Diffraction Would you be able to resolve two points on a piece of paper from further away with a smaller or larger pupil? b) Larger θ > θ1 θ = θ1 θ1=1.22λ/D As diameter D of pupil increases, min angle of resolution θ1 decreases. The points can be further away and still resolvable compared to a smaller pupil size. θ θ Physics and Astronomy Outreach Program at the University of British Columbia 7

Question 4 What wavelength of light would you be able to Vision and Diffraction Question 4 What wavelength of light would you be able to resolve at the furthest distance based on diffraction? a) Red (λ = 650 nm) b) Green ( λ = 550 nm) c) Blue (λ = 450 nm) Physics and Astronomy Outreach Program at the University of British Columbia 8

Question 4 Solution What wavelength of light would you be able to Vision and Diffraction Question 4 Solution What wavelength of light would you be able to resolve at the furthest distance based on diffraction? a) Red (λ = 650 nm) b) Green ( λ = 550 nm) c) Blue (λ = 450 nm) The min angle of resolution is θ1=1.22λ/D. As λ decreases θ1 decreases. Physics and Astronomy Outreach Program at the University of British Columbia 9

Question 5 If the distance from your pupil to the back of Vision and Diffraction Question 5 If the distance from your pupil to the back of your eye increased would that change the minimum angle of resolution? a) Yes, it would decrease b) Yes, it would increase c) No, it would not change Physics and Astronomy Outreach Program at the University of British Columbia 10

Question 5 Solution If the distance from your pupil to the back of Vision and Diffraction Question 5 Solution If the distance from your pupil to the back of your eye increased would that change the minimum angle of resolution? θ1 constant, width w changes a) Yes, it would decrease b) Yes, it would increase c) No, it would not change The min angle of resolution is θ1=1.22λ/D which does not depend on the distance from the pupil to the back of the eye. Physics and Astronomy Outreach Program at the University of British Columbia 11