Q89 / 90 · JEE Main 2018 (15 Apr) · Physics
A particle is oscillating on the -axis with an amplitude about the point with a frequency. A concave mirror of focal length is placed at the origin (see figure).

Identify the correct statements?
(i) The image executes periodic motion.
(ii) The image executes non-periodic motion.
(iii) The turning points of the image are asymmetric with respect to the image of the point at .
(iv) The distance between the turning points of the oscillation of the image is .
A particle is oscillating on the -axis with an amplitude about the point with a frequency. A concave mirror of focal length is placed at the origin (see figure).

Identify the correct statements?
(i) The image executes periodic motion.
(ii) The image executes non-periodic motion.
(iii) The turning points of the image are asymmetric with respect to the image of the point at .
(iv) The distance between the turning points of the oscillation of the image is .
- A(ii, iii)
- Correct answerB(i, iii, iv)
- C(i, iv)
- D(ii, iv)
Solution
Recall the proper formula of mirror formula, , given and then the formula of the concave mirror, . As, image copies the time period of the object is right as well. It will be a periodic motion. For one extreme,
, right arrow.
For other extreme,
. These points are asymmetrical about . Now amplitude of oscillation of image, .
Hence, the correct answer is option: 'B'.