An object is placed 35 cm away from a convex mirror with a focal length of magnitude 15 cm. What is the location of the image?
A. 26.25 cm behind the mirror
B. 10.5 cm behind the mirror
C. 26.25 cm in front of the mirror
D. 10.5 cm in front of the mirror
Correct Answer: B
Explanation
f = 15cm (diverging mirror); u = -35cm(because object is in front of the mirror) v=?
⇒\(\frac{1}{f}\) = \(\frac{1}{v}\) + \(\frac{1}{u}\)
⇒ \(\frac{1}{15}\) = \(\frac{1}{v}\) - \(\frac{1}{35}\)
⇒ \(\frac{1}{15}\) + \(\frac{1}{35}\) = \(\frac{1}{v}\)
⇒ \(\frac{105}{10}\) = \(\frac{1}{v}\)
v = \(\frac{105}{10}\) = 10.5cm
∴The image is 10.5cm behind the mirror, since v is positive.
