Chapter 10: Lens and Mirror Signs Flashcards Preview

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Flashcards in Chapter 10: Lens and Mirror Signs Deck (18):
1

When o of the mirror equation is positive and negative:

Positive: object is in front of mirror (real image)

Negative: object is behind mirror (virtual image)

2

When i of the mirror equation is positive and negative:

Positive: image is in front of mirror (real image)

Negative: image is behind mirror (virtual image)

3

When r of the mirror equation is positive and negative:

Positive: concave mirrors

Negative: convex mirrors

4

When f of the mirror equation is positive and negative:

Positive: concave mirrors

Negative: convex mirrors

5

When m of the mirror and lens equations is positive and negative:

Positive: image is upright (erect)

Negative: image is inverted

6

When absolute value of m of the mirror and lens equations is greater than 1 and les than 1:

Greater than 1: enlarged

Less than 1: reduced

Equal to 1: same size

7

When o of the lens equation is positive and negative:

Positive: object on side of lens light is coming from (virtual side)

 

Negative: object on side of lens light is going to (real side)

8

When i of the lens equation is positive and negative:

Positive: image on side of lens light is going to (real side)

 

Negative: image on side of lens light is coming from (virtual side)

9

When r of the lens equation is positive and negative:

Positive: when on real side (convex surface as seen from side light is coming from)

 

Negative: when on virtual side (cocave surface as seen from side light is coming from)

10

When f of the lens equation is positive and negative:

Positive: converging lens

Negative: diverging lens

11

Law of Reflection equation:

θ1 = θ2

where θ1 is the incident angle and θ2 is the reflected angle

the angles are always measured from normal (a line perpendicular to the surface of the medium)

12

Equation to determine the object or image distance from a mirror, focal length, or radius of curvature:

1/o + 1/i = 1/f = 2/r

where o is the distance of the object from the mirror, i is the distance of the image from the mirror, f is the distance from the focal point to the mirror (focal length), and r is the distance between the center of curvature and the mirror (for spherical mirrors)

units = m-1

13

Equation to find the magnification of an image for both mirrors and lenses:

m = - i/o

where o is the distance of the object from the mirror and i is the distance of the image from the mirror or lens

if the absolute value of m is less than 1, the image is reduced

if the absolute value of m is greater than 1, the object is enlarged

14

Equation to determine the index of refraction:

n = c/v

where c is the speed of light in a vacuum (3.8 X 108), v is the speed of light in the given medium, and n is the index of refraction

15

Equation to find the degree of refraction of a light ray upon entering a new medium:

n1sinθ1 = n2sinθ2

theta is always measured with respect to the perpendicular to the boundary

16

Equation to determine the critical angle:

derived from Snell's Law

sinθc = n2 / n1

17

Equation to determine object distance (o), image distance (i), focal length (f), and magnification (m) for lenses:

1/o + 1/i = 1/f

m = -i/o

18

Equation to determine the focal length in lenses where thickness cannot be ignored:

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

where n is the index of refraction of the lens material, r1 is the radius of the curvature of the first lens surface, and r2 is the radius of curvature of the second lens surface