Answer to Question #214401 in Electricity and Magnetism for John Mark

Question

A 1.50-cm-high object (upright arrow) is placed 20.0 cm from a concave mirror with radius of curvature 30.0 cm. Determine (a) the position & (b) the size of the image. Construct a ray-diagram for the image formation of this object on the concave mirror by using appropriate scale.

Answer 1

Gives

$d_0=20cm,f=\frac{R}{2}=\frac{30}{2}=15m$

$d_i=?$

$\frac{1}{d_0}+\frac{1}{d_i}=\frac{1}{f}$

$\frac{1}{20}+\frac{1}{x}=\frac{1}{15}$

$3x+60=4x$

$x=60cm$

The image of distance(x)=60cm

The image is 3 times as far from the mirror as the object so it Will be 3times as large or

r=4.5cm tall.