Question

One of the following does not apply to a concave mirror. This is:; A. focal length is positive; B. image distance can be positive or negative; C. image distance is always negative; D. height of image can be positive or negative

Answer 1

Answer:

A.). focal length is positive?

Answer 2

Answer:

"Focal length is positive" is one of the option that doesn't apply for the concave mirror.

Explanation:

• The focal length is negative for a concave mirror since according to the Cartesian Sign, the object is placed "in front of the mirror" and the sign of the object is taken as 'negative'.
• The 'image distance' can be negative or positive depending upon the object distance and it is positive if the image is 'in front of the mirror' and negative if it is behind the mirror.
• If the image is erect, the height of the image is positive and if it is inverted, then the height of the image is negative.