Lenses & Mirrors
How curved mirrors and lenses form images
Do Now: Look at your reflection in the back of a shiny spoon, then flip it over. Why are you upside down on one side and right-side up on the other?
One side of the spoon caves in (concave) and the other side bulges out (convex). The two shapes bend light in opposite ways. This unit shows you how to predict exactly what image each one makes.
Try It First
Pick a mirror or a lens, then drag the object and watch the image change.
Drag the orange object. Turn rays on and off with the check boxes.
Lessons
NYS P-12 Science Learning Standards, Physics: HS-PS4-6 — Use mathematical models to relate image size and location, object size and location, and focal length for plane, convex, and concave mirrors and biconvex and biconcave lenses.
The Right Optic for the Job
An engineering team is choosing optical devices for several products: a vehicle side mirror, a flashlight reflector, a reading magnifier, and a peephole viewer.
Which device is the best match for a flashlight reflector that produces a narrow beam?
▶ Want a challenge? Open 6 more Regents-style questions (harder · mixed formats)
Challenge score: 0 / 6
C1. Which device gives the vehicle side mirror the widest field of view?
C2. Place a check mark in two boxes to indicate the devices that can project a real image of a real object onto a screen.
C3. A student makes the following claim.
Place a check mark in either the Support or Refute box. Justify your response.
C4. The reading magnifier is a converging lens with a focal length of 8.0 cm, held 6.0 cm above the page. (A negative image distance means a virtual image on the same side of the lens as the object.) Substitute numerical values into a mathematical representation that can be used to determine the image distance. Then calculate it.
C5. Which pair of devices can only form virtual images of real objects?
C6. The team wants the flashlight to have an adjustable beam that can switch between a narrow spot and a wide flood. Describe how moving the bulb relative to the concave mirror’s focal point could produce each beam, and explain why.