Question

A cell phone has a camera with a lens diameter D = 3mm and a focal length of f = 4.25mm. (1mm = 10⁻³m.) For this problem take the wavelength of light to be 500 nm (5 × 10⁻⁷) m. Assume the sensor in the phone is 5mm x 5mm and that each pixel has a size of 2μm x 2μm. (1μm = 10⁻⁶m.)

a. If a vertical meter stick is located 5m from the phone and the image of the meter stick is in focus, how far from the lens is the sensor?

b. What is the size of the meter stick on the sensor?

c.What is the angular size of an object which has a height of 5mm if it is located 5m from the phone?

d.What is the angular size of a pixel if the camera is focused on an object far away?

e.What is the diffraction limit for the cell phone angular resolution?

please help

Answer 1