Lens equation

The d_o will be a _________________ value.

• positive
• negative

The d_i for a real image will be a _________________ value

• positive
• negative

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

• positive
• negative

The value for f is negative in this diagram.

• True
• False

In the thin lens equation, do represents 

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

A converging lens produces an image twice the size of the original. If the object is placed 0.40 m from the lens, and the image produced is 0.80 m from the lens. What is the focal length of the lens? 

• 0.351 m
• 0.267 m
• 0.416 m
• 0.112 m

A tree 20 m high is located 40 m from the converging lens of focal length 0.08 m.Calculate the distance from the lens to the image.

• 0.08 m

• 0.01 m

• 0.10 m

• 0.20 m

The h_i in this picture is negative.

• True
• False

The h_{o in this diagram is positive.}

• True
• False

An object is located 35.0 cm from a convex lens. The lens forms a real image at a distance of 15.0 cm. What is the focal length?

• 0.0953 cm

• 10.5 cm

• 26.2 cm

• 0.0678 cm