Focal length of the concave mirror shown in figure in 20 cm.
`ab=1mm `
and `bc=2mm`
For the given,situtation,make its image.

Explanation

`u=-30 cm` and `f=-20cm`
Using the mirror formula,`(1/v)+(1/u)=(1/f)`, we have
`(1/v)+(1/-30)=(1/-20)`
jm,Solving this equation ,we get
`v=-60 cm`
Now, `m=-(v)/(u)=-(-60)/(-30)=-2`
Now c point is 2 mm above the principal axis and magnification is -2. Hence, image c' will be
formed `4mm` below the principal axis, similarly a point is `1mm` below the principal axis and
value of m is -2, Hence image a' is formed `2mm` above the pricipal axis, Image with ray
diagram of c is as shown below.