# Use the mirror equation to deduce that an object placed between the pole and focus of a concave mirror produces a virtual and enlarged image. - Physics

Numerical

Use the mirror equation to deduce that an object placed between the pole and focus of a concave mirror produces a virtual and enlarged image.

#### Solution

For a concave mirror, the focal length (f) is negative.

∴ f < 0

When the object is placed on the left side of the mirror, the object distance (u) is negative.

∴ u < 0

It is placed between the focus (f) and the pole.

∴ f > u > 0

1/"f" < 1/"u" < 0

1/"f" - 1/"u" < 0

For image distance v, we have the mirror formula:

1/"v" + 1/"u" = 1/"f"

1/"v" = 1/"f" - 1/"u"

∴ 1/"v" < 0

v > 0

The image is formed on the right side of the mirror. Hence, it is a virtual image.

For u < 0 and v > 0, we can write:

1/"u" > 1/"v"

v > u

Magnification, m = "v"/"u" > 1

Hence, the formed image is enlarged.

Concept: Ray Optics - Mirror Formula
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#### APPEARS IN

NCERT Physics Part 1 and 2 Class 12
Chapter 9 Ray Optics and Optical Instruments
Exercise | Q 9.15 (d) | Page 345
NCERT Class 12 Physics Textbook
Chapter 9 Ray Optics and Optical Instruments
Exercise | Q 15.4 | Page 346

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