Question

A 1.2 cm tall object is placed 4.0 cm from a double convex lens having a 12 cm focal length.
(a) Show your calculation of the image location.
(b) Explain why the image is real or virtual.
(c) Show your calculation of the image height.
(d) Explain why the image is upright or inverted.
(f) On graph paper, place the principle axis, lens, object, and
focal length to scale. Add three principle rays to the graph to locate and define the image.

Answer 1

Using the lens formula

$\frac{1}{v}-\frac1u=\frac1f$

$\frac1v-\frac{1}{-4}=\frac1{12}$

$v=-6cm$

here v is negative which means that the image formed is virtual

m=$\dfrac vu$ =$\dfrac IO$

$m=\frac{-6}{-4}=\frac{I}{1.2}\\I=1.8$

here value of I is positive which means that the image is upright