Physics doubt -

Question

In a concave mirror, when an object is placed between C and F, the image formed is real, inverted and magnified. But to find magnification, we need to divide the image height(-) with the object height(+). The final answer would be negative. That is less than 1. And if magnification is less than 1, the image is said to be diminished. So can we still call the image magnified?

Answer 1

Long time no see. Frankly speaking I am not very happy when in the formula for magnification we are using the minus sign. By definition magnification is a ratio of the size of the image to the size of the object. Size of image or object is length. It means we are dealing with 2 positive numbers, and their ratio is also positive. Usually minus sign means that the image is inverted. Yes, if magnification is greater than one then size of the image is greater than of the object. If less - than vice versa.

The same we have in case of accelerated motion. We can talk about positive and negative acceleration, but still we say that this is ACCELERATED motion. Although if acceleration is positive the speed of the body increasing, and if the acceleration is negative than the speed of the body is decreasing. We can say that it is decelerated motion, but in many cases we still use the expression accelerated motion.

This analogy helps to understand how we are using the expressions or words to describe different phenomena in general. But when we see the final answer, we can make the right conclusion about the reality and interpret it in a right way.