Lens Equation Problems

In the thin lens equation, do represents 

• Distance of the object from the lens
• Distance of the image from the lens

The d_o will be a _________________ value.

• positive
• negative

The d_i for a real image will be a _________________ value

• positive
• negative

The d_o can be a negative value.

• True
• False

The d_i for a virtual image will have a ______ value.

• positive
• negative

The value for f is negative in this diagram.

• True
• False

Magnification is always positive.

• True
• False

An object is placed 8 m in front of converging lens. A real image is produced at 12 m. Find the focal distance of the lens.

• 4.8

• 6.2

• 3.5

• 8.1

A 15.0 m object is placed 60.0 m from a convex lens, which has a focal length of 15.0 m. Use the thin lens equation to find the distance of the image.

• 10

• 20

• 30

• 40

A 15.0 m object is placed 30.0 m from a convex lens, which has a focal length of 15.0 m. Use the thin lens equation to find the distance of the image.

• 10

• 20

• 30

• 40