Question

Class Management | Help Lesson 9 Optical Systems Begin Date: 6/10/2019 12:01:00 AM - Due Date: 10/27/2019 11:59:00 PM End Date: 11/3/2019 11:59:00 PM (15%) Problem 12: A friendly firefly sits patiently on an optical bench while light from its glow propagates through a thin lens of focal length 6.9 cm and then through a thin lens of focal length -9.9 cm. The firefly sits 19.8 cm from the first lens and the lenses are fixed 19.8 cm apart. A 14% Part (a) Find the distance from the first lens, in centimeters with its sign, of the image of the firefly formed by that lens. A 14% Part (b) This image is ... A 14% Part (c) Find the lateral magnification, with its sign, of the first lens. A 14% Part (d) Find the distance from the second lens, in centimeters with its sign, of the firefly's image that the second lens forms. A 14% Part (e) This image is ... A 14% Part (f) Find the lateral magnification, with its sign, of the second lens. A 14% Part (g) Find the total lateral magnification, with its sign of the two-lens system Grade Summary Deductions 0% Potential 100% m = HOME sin() cotan atan cos asin() acotan tan) acos sinh u E ( ) 1^ ^ 1 * 7 4 1 8 5 2 9 6 3 Submissions Attempts remaining: 5 (5% per attempt) detailed view

Answer 1

(a)

use thin lens equation

1/f = 1/p + 1/q

1/q = 1/f - 1/p

1/q = 1/6.9 - 1/19.8

q = 10.6 cm

______________

(b)

the image is real, inverted

____________

(c)

m = -q / p

m = - 10.6 / 19.8

m = - 0.5348

____________

(d)

now image from first lens becomes object for second lens

so,

object distance for second lens, p = 19.8 - 10.6 = 9.2 cm

so,

1/q = - 1/9.9 - 1/9.2

q = - 4.768 cm

______________

(e)

image is virtual, upright

____________

(f)

m = - ( - 4.768) / 9.2

m = 0.518

____________

(g)

M = 0.518 * - 0.5348

M = - 0.2772