Question

The magnification by a concave lens is always positive, and less than one, $\left(<1\right)$. Describe the nature of the images formed by a concave lens.

Answer 1

Step 1:

1. Magnification of the lens is the ratio of height (size) of the image to the height (size) of the object.
2. When the height of image is positive, the magnification is positive.
3. When the height of image is negative, the magnification is negative.

Step 2:

1. When the value of the magnification of the lens is positive, it produces virtual and erect image.
2. When the value of the magnification of the lens is negative, it produces real and inverted image.

Step 3:

1. When the value of magnification of a lens is equal to one,$\left(=1\right)$, the size of the image is same as that of the object.
2. When the value of magnification of a lens is smaller than one,$\left(<1\right)$, the size of the image is smaller than that of the object, that is, the diminished image is formed.
3. When the value of magnification of a lens is greater than one,$\left(>1\right)$, the size of the image is greater than that of the object, that is, the magnified image is formed.

Step 4:

1. As per the given information, the value of the magnification of a concave lens is always positive and $\left(<1\right)$, it implies that the images produced by the concave lens are virtual, erect, and diminished.
2. Thus, nature of images produced by the concave lens are virtual, erect, and diminished.