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?
- 26.25 cm behind the mirror
-
10.5 cm behind the mirror
- 26.25 cm in front of the mirror
- 10.5 cm in front of the mirror
The correct answer is: 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.