1. a) A photon has energy 5 eV. What is the wavelength of the photon? Can human eyes see this photon? Why and why not?

b) A photon has energy 1.5 eV. What is the wavelength of the photon? Can human eyes see this photon? Why and why not?

2. a) Assume that a fly is 3mm in diameter, and that the image distance for a normal eye can be taken to Q = 0.02 m. Compute the size of the image formed on the retina of a fly sitting on a wall 3.0 m away.

b) If you are watching a football from the end of a large stadium, what size will be the image of the football (L= 0.3 m) on you retina when the football is at the other end of the field, 150 m away from your seat?

3. Describe the strength of a lens needed to correct a myopic (near-sighted) eye which has a far pint of P = 1.0 m (far points means the greatest distance for which an object can be imaged on the retina). As above, take the image (lens to retina) distance to be Q = 0.02 m.

4. Determine the strength of a lens needed to allow a person with a far-sighted eye with a near point of Pnar= 2.0 m (near point means the closest distance for which an object can be imaged on the retina) to read comfortably at 0.25 m?

5. a) If an emmetrope has an accommodation of 53 D, what is the person's near point?

b) If a former emmetrope wears reading glasses of +2D to read at a distance of 25 cm, what is the near point without glasses?