An object is placed in hunt of a concave mirror at a distance thrice its focal length (3f). The image is formed at:

Correct option is B

Correct Answer:

B) A point between F and C

Explanation:

For a concave mirror, when an object is placed beyond the center of curvature (C), specifically at a distance of 3f (three times the focal length), the following occurs:

1. Position of the Image:
• The image is formed between the focus (F) and the center of curvature (C).
• This is determined using the mirror formula: $$\frac{1}{f} = \frac{1}{v} + \frac{1}{u}$$​ Here:
• f is the focal length,
• v is the image distance,
• u=−3f (object distance, negative as per the sign convention).
2. Characteristics of the Image:
• The image is real (forms on the same side as the object).
• It is inverted.
• It is diminished in size compared to the object.

Key Points:

• If the object is placed at infinity, the image forms at focus (F).
• If the object is at C, the image also forms at C.
• If the object is beyond C, the image forms between F and C, as in this case.
• If the object is between F and C, the image forms beyond C.