A 10.00cm. tall light bulb is placed at a distance of 90.0cm from a concave mirror having a focal length of 21 cm . Determine the images l distance and the image size
Given
f = -21
u = -90
"\\frac{1}{f} = \\frac{1}{v} + \\frac{1}{u}"
"\\frac{1}{-21} = \\frac{1}{v} +\\frac{1}{-90}"
"\\frac{1}{v} = - \\frac{1}{21} + \\frac{1}{90}"
On solving above, we get
v =, -27.4 cm. (Distance of image)
For image size, we have
m = "- \\frac{v}{u} = \\frac{hi}{ho}"
"- \\frac{-(-27.4)}{-90} = \\frac{10}{ho}"
On solving above, we get
ho = 32.8 cm. (Size of Image)
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