Ray Optics PhET Lab Name: __Lila Abu-Saleh__ Introduction: When you hold your glasses far away from your face, what do you see?

Conclusion Questions and Calculations: 5 points each  Highlight your correct answer and show your work for numerical questions.

1. Images found behind a lens are ( real / virtual ) images that will be ( upright / inverted ).

2. As the radius of curvature of the lens increases, the focal point of that lens becomes ( closer to / further away from ) that lens.

3. As the refractive index of the lens increases, the focal point of that lens becomes ( closer to / further away from ) that lens.

4. What advantage does a larger lens have over a smaller lens (all other characteristics being equal)?

[Answer]

5. What was the focal distance (f) when the radius of curvature was 0.70 and index of refraction was 1.8? ______f = 0.4375 m_______

6. Calculate the radius of curvature of a lens with a focal distance of 40. cm and an index of 1.2. ________R = 16 cm_________

7. An object placed 35. cm away from a lens projects a real image 0.55m behind the lens. What is this lens' focal distance? _________f = 21.4 cm_________

8. What is the lens' magnification? _______m = 1.57_________

9. An object 20. cm to the left of a convex lens is 1.0 m in height. What is the height and location of its image if the lens has a magnification of -2.0? ________0.02______ m and _______40______ cm on the ( left / right ) side of the lens

10. Imagine you are nearsighted (can only see close objects clearly and far objects are blurry). At your last eye doctor's appointment, your optometrist tells you that she will need to increase your prescription because as it turns out light is focusing "too soon" or in front of your retina. You respond, "Obviously, I will need a ( converging / diverging ) lens with a ( higher / lower ) focal distance."