Question

Which of the following is correct about concave lens?

• A. It is a diverging lens.
• B. Image is always formed either at focus or between focus and optical centre.
• C. It always forms diminished image.
• D. All are correct.

Answer 1

The correct option is D All are correct.

Images formed by a thin concave lens for different positions of an object are discussed here.
1. When the object is at infinity

For image,
Position : at focus $F_1$
Nature : Virtual, erect and magnification is positive
Size : highly dimished $(|m|<<1)$

2. When the object is in between infinity and $F_1$


For Image:
Position : between $F_1$ and O
Nature : virtual and erect $(m=+ve)$
Size : diminished $(|m|<1)$