Question

An object is placed at a distance of 20 cm from a convex mirror of focal length 15cm find the position and nature of the image

Answer 1

Given;
u=-20cm
f=+15cm ( focal length is positive becaue in convex mirror image always form in right side or acoording to sign convention image form upward to the principal axis so it is taken as positive.
v=?
1/f=1/v+1/u
1/15=1/v+1/-20
1/15+1/20=1/v
4+3/60=1/v
7/60=1/v
(by cross multiplication)
7v=60
v=60/7
v=+8.57

NATURE; VIRTUAL AND ERECT

Answer 2

$\bf\huge u = -20cm , f = 15cm$

$\bf\huge\frac{1}{f} = \frac{1}{u}+\frac{1}{v}$

$\bf\huge\frac{1}{v} = \frac{1}{15} - \frac{1}{-20}$

$\bf\huge\frac{1}{v} = \frac{1}{15} - \frac{1}{20}$

$\bf\huge\frac{1}{v} = \frac{7}{60}$

$\bf\huge\texttt v = 8.57 cm$

$\bf\huge\boxed{\boxed{\:Nature\:of\:Image\:=\:Virtual}}}$