Physics

posted by .

A convex mirror has a focal length of
-18 cm. How far behind the mirror does the image of a person 3.0 m away appear? The answer must be in cm.

The equation to use woulde be:
1/f = 1/do + 1/di

do = 300 cm
f = would it be -18 cm or 18 cm???

  • Physics -

    Use negatve numbers for the focal length of a convex mirror. They already tell you to use -18.

    -1/18 = 1/300 + 1/di
    1/di = -.058888
    di = -16.98

    Negative numbers for the di mean that the image is behind the mirror. This would be typical of a mirror used as a wide-angle side view mirror for a car, or for viewing aorund a corner.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Physics

    A candle is placed 17.0 cm in front of a convex mirror. When the convex mirror is replaced with a plane mirror, the image moves 6.0 cm farther away from the mirror. Find the focal length of the convex mirror. _______cm
  2. Physics

    (1) A virtual image -7 cm tall and 17 cm away from a mirror is created by an object 7 cm away from a mirror. How tall is the object?
  3. Physics

    (1) A virtual image -7 cm tall and 17 cm away from a mirror is created by an object 7 cm away from a mirror. How tall is the object?
  4. physics

    A 4.5 cm tall object is placed 20 cm in front of a spherical mirror. It is desired to produce a virtual image that is upright and 3.5 cm tall. (a) What type of mirror should be used?
  5. Physics

    The image of a crayon appears to be 20.6 cm behind the surface of a convex mirror and is 3.32 cm tall. The mirror’s focal length is 52.6 cm. a) How far in front of the mirror is the crayon positioned?
  6. physics

    A person stands in front of a mirror at an amusement park. the person is left of a mirror. the mirror shows an upright image of the person that seems to be 4.0 meters behind the mirror. assume the image is 3.5 times the person's height. …
  7. Physics

    A mirror produces an image that is located 50.0 cm behind the mirror, when the object is located 5.50 cm in front of the mirror. (a) What is the focal length of the mirror?
  8. physics

    A convex spherical mirror has a focal length of -20 cm. An object is placed 30 cm in front of the mirror on the mirror's axis. Where is the image located?
  9. Physics (Mirror Rays)

    3. When an object is located very far away from a convex mirror, the image of the object is 18 cm behind the mirror. Using a ray diagram drawn to scale, determine where the image is located when the object is placed 9.0 cm in front …
  10. Physics 11

    Confused about the formula (1/-f)= (1/do)+(1/-di) For locating an image for a convex mirror. A rose is placed 15cm in front of a convex mirror of focal length 10cm. Determine the location of the image using the mirror equation. (1/-10)=(1/15)+(1/-di) …

More Similar Questions