Question

7) Draw a ray diagram for the following situation and use it to determine the location and size of the image. The object is 3.0cm tall. 10.0cm to the right of the object is a diverging lens with a focal length of -4.0cm. Draw the lens as being at least 6.0cm tall. You only need to draw two rays. Answers that are not clearly based on the diagram will not be accepted as correct.

Answer 1

Find image position using lens equation 1_1_1 P Rearrange for image position, i and use the fact that focal length for diverging lens is negative 1 1 1 - i i = p+ Substitute the numerical values -(4cm) (10 cm i= 4 cm +10 cm = -2.857 cm -2.86 cm Magnification: M = 同一 Substitute the numerical values 2.857 cm M= 10 cm 3 cm Solve for height of the image h = 0.857 cm $ 0.86 cm

Ray diagram:

3 cm 0.86 cm 0 BOF F B 2.86 cm 10 cm 4.0 cm

In this case, the image formed ( 2.86 cm ) before focal point of lens ( here 4 cm ) and diminished , that means

size of image ( 0.86 cm ) is less than size of object (3.0 cm ).