<A NAME="top"></A> Physics Review Question Unit: Year: 1992 Question#: 89 Question: If the distance between an object and a concave (converging) mirror is more than twice the focal length of the mirror, the image formed will be (1 ) real and behind the mirror (2 ) real and in front of the mirror (3 ) virtual and behind the mirror (4 ) virtual and in front of the mirror What is this question really asking? Explanation by: Apia A [ Return to question menu ] <A NAME="answerA"></A> Answer 1 real and behind the mirror INCORRECT This answer can not be correct because for a mirror an image cannot be real and behind the mirror. If an image in a mirror is real it is on the same side as the object . return to top <A NAME="answerB"></A> Answer 2 real and in front of the mirror CORRECT For concave mirrors an image is real if the object distance is greater than the focal length and so in this question the object length is twice the focal length. This means that the image is real and since the image is real it must be both real and in front of the mirror. return to top <A NAME="answerC"></A> Answer 3 virtual and behind the mirror INCORRECT Since the object is outside the focus the image cannot be virtual. return to top <A NAME="answerD"></A> Answer 4 virtual and in front of the mirror INCORRECT (The same as 3) The image cannot be virtual return to top <A NAME="what"></A> What's this question really asking? When is the image in a concave (converging ) mirror real or virtual? return to top |
[Physics Lessons] [Physics Review] [Physics Links]
This web site is designed and maintained by Science Joy Wagon and may
not be reproduced or redistributed without written permission from Science Joy Wagon. |