hu 2:39 PM Nic PHYS 205 Spring17 PARKER: HW: Reflection, Refraction, Optics Appl
ID: 2075151 • Letter: H
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hu 2:39 PM Nic PHYS 205 Spring17 PARKER: HW: Reflection, Refraction, Optics Apple Yahoo! Google Maps YouTube wikipedia Google Dictionary c h Dictionary News Popular Welcome, Nicol Mail nickoleg. 4/5/2017 11:55 PM G20/40 G 3M30/2017 08:10 AM Grade bo Print Icalculator Periodic Table Question 5 of 13 Sapling Learning h firefly sits on the axis of, and 10.9 cm in front of the thin lens A, whose focal length is 6.47 cm. lens A there is another thin lens, lens B, with focal length 21.5 cm. The two lenses share a common axis and are 57.9 cm apart. Is the image of the firefly that ens B forms real or virtual? O Real O Virtual How far from lens B is this image located (expressed as a positive number? cm What is the height of this image (as a posisve number)? s this image upright or inverted with respect to the firefy? O Upright O Inverted about us careers partners priv o pooey terms ofuse contact us helpExplanation / Answer
Assuming both lenses are converging lenses,
Image formed by first lens will be behind the lens and real since object distance greater than focal length of lens 1.
Here u = 10.9
f = 6.47
Therefore
1/v = 0.063
v 15.92 cm behind the lens.
since both lenses are seperated by distance of 57.9 cm,
distance of image formed by lens 1 from lens 2 = 57.9 - 15.92 = 41.98 cm
This will act as object for lens 2
since object distance is greater than focal length of lens 2 ( 41.98 > 21.5 ), the image will form behind the mirror.
1/v +1/u = 1/f
Here u = 41.98
f = 21.5
1/v = 0.0227
v = 44.07 cm
The image is Real and located 44.07 cm behind the second lens
Magnification = - v/u for 1 lens.
Since the final image is magnified twice
M = - v1/u1 * - v2/u2
= - 15.92/10.9 * - 44.07/41.98
= 1.533
The image formed is upright.
The height of firefly = 1.533 * 6.85 = 10.50 mm
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