theresaanderson
contestada

You place a light bulb 8 cm in front of a concave mirror. You then move a sheet of paper back and forth in front of the mirror. The image of the light bulb focuses on the paper when the paper is 12 cm in front of the mirror. What is the focal length of the mirror? Please show work too.

Respuesta :

sorry - late reply...just stumbled across tis...hope u can still use it :)


By the mirror equation: 1/di + 1/do = 1/f


where di = distance to image = +12cm (+ for real image)


and do = distance to object = +8cm


Substitute and solve for f, the focal length


1/12 + 1/8 = 1/f

1/f = (8 + 12) / 12 * 8 = 20/96

so f = 96/20 = 4.8 cm
Eduard22sly

The focal length of the mirror is 4.8 cm

Data obtained from the question

From the question given above, the following data were obtained:

•Object distance (u) = 8 cm

•Image distance (v) = 12 cm

•Focal length (f) =?

How to determine the Focal length

The focal length of the mirror can be obtained by using the mirror equation as follow:

1/f = 1/u + 1/v

Rearranging,

f = uv / (u + v)

f = (8 × 12) / (8 + 12)

f = 96 / 20

f = 4.8 cm

Thus, the focal length of the mirror is 4.8 cm

Learn more about mirror equation:

https://brainly.com/question/25838822

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