Magnification and Power Flashcards
What type of lens is used in magnifying glasses and cameras?
Converging
What kind of image do magnifying glasses produce?
magnified and virtual
The object being magnified must be closer to the lens than the …
Focal length
What can’t you do with virtual images?
You can’t project a virtual image onto a screen
What is the magnification formula?
Magnification = Image height / Object height
Focal length is elated to [ ] of the lens
The power
The shorter the focal length, the more/less powerful the lens, Why?
More
The more strongly it converges rays of light
What is the formula for the power of a lens?
Power (D) = 1 / Focal length (m)
P = 1/f
D stands for dioptres, the unit for lens power
Is the power for a converging lens Negative or positive? What about for diverging?
Converging = Positive Diverging = Negative
What is the focal length determined by?
The refractive index of the lens material
The curvature of the two surfaces of the lens
To get more power do you want the surface ;to be more or less curved?
MORE
For a given focal length, the [ ] the refractive index of the material used to make the lens, the flatter the lens will be.
Greater
How can more powerful lenses be made thinner?
Use a material with a HIGHER refractive index
