You use a lens to look at a flower When you put the lens 30

You use a lens to look at a flower. When you put the lens 30 mm away from flower, the flower appears to be 0.25 m in front of your eye (this is called the near point of your eye). However, the actual distance from your eyes and the flower is 130 mm.

a. What is the focal length of the lens?

b. Is the image real or inverted?

c. Is the image smaller or larger than the flower?

Solution

Distance from centre of lense to image = Image distanec= 130 + 30 =160 mm

Distance from centre of lense to object = Object distance= 30 mm

1/ Focal Length= 1 / Object distance + 1 / Image distance

= 1/30 + 1/160

Focal lenght = 25.26mm

2. Image is inverted. Also real.

3 . Small