Converging Lens Magnification Problem

AI Thread Summary
The discussion centers on calculating the magnification of a virtual image formed by a converging lens with a focal length of 15.0 cm. The user initially calculated the object distance (p) and magnification (M) but received an incorrect answer due to a sign convention error, as the distance for a virtual image (q) should be negative. The correct formula for magnification is M = -(q/p), with the revised value for q being -26 cm. After correcting the sign, the magnification calculation needs to be adjusted accordingly. The thread highlights the importance of adhering to proper sign conventions in optics calculations.
soccerjayl
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What am I missing here?

A person looks at a gem using a converging lens with a focal length of 15.0 cm. The lens forms a virtual image 26.0 cm from the lens. Determine the magnification.

(1/p)+(1/q) = (1/f)
p=?
q=26 cm
f=15 cm

(1/15)-(1/26)= Ans^-1 = 35.5 cm (p)

Magnification= -(q/p)
M= -(26/35.5)
M= -0.733

Answer [-.733] has been marked wrong. What did I do?
 
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check your sign convention

soccerjayl said:
(1/p)+(1/q) = (1/f)
p=?
q=26 cm
f=15 cm
Your sign convention is incorrect. "q" for a virtual image is negative.

Welcome to PF, by the way.
 
whoa thanks

i apologize, i knew that...just dumb tonight

thanks for the welcome
 
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