10th class physical science 1st lesson reflection of light and curved surfaces lab activity
Answers
Explanation:
Linear magnification and the mirror formula
Linear magnification is defined as the ratio of the image size to the object size;
Magnification= Image size/ Object size.
Similarly, it can be expressed as the ratio of the distance of the image to the distance v of object u from the mirror. Magnification has no unit.
Suppose an object is placed u cm in front of a spherical mirror of focal length f such that the image is formed v cm from the mirror, then u, v and f are related by the equation;
1/f= 1/u + 1/v.
This equation is referred to as the mirror formula. The formula holds for both concave and convex mirrors.
When applying the mirror formula, it is necessary to observe the following points:
That all distances are measured from the mirror as the origin.
All real distances are positive while all virtual distances are negative.
A concave mirror has a positive focal length while a convex mirror has a negative focal length.
Example
Determine the position, size and nature of the image of an object 4cm tall placed on the principal axis of a concave mirror of focal length 15cm at a distance 30cm from the mirror.