Lenses

Question 1

Do rays con/diverge for concave/vex lenses?

Answer 1

concave lenses diverge, convex lenses converge

Question 2

What type of img do you get w/ convex lenses?

Answer 2

inverted real img

Question 3

What happens if img at focal point of convex lens?

Answer 3

no img

Question 4

What happens if img behind focal point of convex lens?

Answer 4

real, inverted, bigger

Question 5

What happens if img at 2nd focal point of convex lens?

Answer 5

real, inverted, same size

Question 6

What happens if img behind 2nd focal point of convex lens?

Answer 6

real, inverted, smaller

Question 7

What happens if img in front of focal point of convex lens?

Answer 7

virtual, upright, bigger

Question 8

What happens if img is in front of focal point of concave lens?

Answer 8

virtual, upright, smaller

Question 9

How to find power of lens?

Answer 9

D = 1/m (D = Diopter)

Question 10

Pos/neg di vs do mean what?

Answer 10

Pos = opposite side of lens from light source (ie. real), neg = same side of lens as light source (ie. virtual) vs pos = same side of lens as light source, neg = opp side of lens as light source (extremely rare)

Question 11

Are real/virtual imgs pos or neg distance?

Answer 11

Real = pos distance, virtual = neg distance

Question 12

True or false: diverging lens ALWAYS give virtual img

Answer 12

True

Question 13

Pos/neg f and r mean what?

Answer 13

Pos = converging lens (ie. convex)
Neg = diverging lens (ie. concave)

Question 14

Lensmaker eqn for thick/real lenses

Answer 14

1/f = (n-1)(1/r1 - 1/r2)

n=refraction index
r1=radius of curvature for first lens, r2=radius of curvature for second lens

Question 15

What does M tell you?

Answer 15

+ = upright, - = inverted; abs(value) < 1 —> smaller, abs(value) > 1 —> bigger, abs(value) = 1 —> same

Question 16

If you have multiple lenses, how do you find total f, P, and M?

Answer 16

For f and P, add em up (1/f1 + 1/f2 + … 1/f_n; P1 + P2 + … P_n)
For M, multiply (M1 * M2 * … M_n)

Question 17

Spherical aberration vs chromatic aberration vs dispersion

Answer 17

Blurring of periphery due to inadequate reflection of parallel beams at edge of mirror or inadequate refraction of parallel beams at edge of lens vs dispersive effect within a lens vs when various wavelengths of light separate from e/o (ex: white light splitting into different colors thru a prism; this can happen during diffraction or refraction)