Physics Review Question Unit: Geometric optics Year: 1995 Question#: 87 Question: A concave mirror has a radius of curvature of 0.60 meter. When an object is placed 0.40 meter from the reflecting surface, the image distance will be (1 ) 0.10 m (2 ) 0.20 m (3 ) 0.83 m (4 ) 1.2 m What is this question really asking? Explanation by: Chris [ Return to question menu ] Answer 1 0.10 m INCORRECT This would be the answer if you you subtracted the object distance from .3, the focal radius. Remember to use the equation 1/di+1/do=1/F. Using the reciprocals of the numbers above will yield the right answer. return to top Answer 2 0.20 m INCORRECT Subtracting the object distance from the radius of curvature is not the way to find the right answer. return to top Answer 3 0.83 INCORRECT .83 is incorrect return to top Answer 4 1.2 m CORRECT Radius of curvature=2f Focal length=f Focal length=Radius of curvature/2 f=.6/s f=.3m solve for the image distance return to top What's this question really asking? This question is asking how far an image of an object will appear from the mirror in a concave mirror. return to top
 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. Contact with comments.