an image of small size can be obtained on a screen placed at 2.0m from the object. it can be done by using?
(a)concave mirror of focal length 0.5m
(b)concave mirror of focal length greater than 0.5m
(c)concave mirror of focal length less than 0.5m
(d) concave lens of focal Length less than 0.5 m
plz explain
Dear Student,
The image can not be formed on screen in case of convex lens so the option D is incorrect. Now, if we consider the case of concave mirror then, real and diminished image is formed when object is placed between F and 2F and the image is formed beyond 2F. Thus here 2 m is greater than 2f . Thus focal length of concave mirror is smaller than 1m. Thus option b can also be incorrect as greater than 0.5 is not compulsorily smaller than 1. Thus, option a and c can be correct, as concave mirror can have both focal lengths smaller than or equal to 0.5 m.
Regards
The image can not be formed on screen in case of convex lens so the option D is incorrect. Now, if we consider the case of concave mirror then, real and diminished image is formed when object is placed between F and 2F and the image is formed beyond 2F. Thus here 2 m is greater than 2f . Thus focal length of concave mirror is smaller than 1m. Thus option b can also be incorrect as greater than 0.5 is not compulsorily smaller than 1. Thus, option a and c can be correct, as concave mirror can have both focal lengths smaller than or equal to 0.5 m.
Regards