Object at Any Finite Distance in a Convex Mirror : āĻāϤā§āϤāϞ āĻĻāĻžāĻĒā§āύāϤ (Convex Mirror) āϝāĻŋāĻā§āύ⧠āϏāϏā§āĻŽ āĻĻā§ā§°āϤā§āĻŦāϤ āĻŦāϏā§āϤ⧠āĻĨāĻžāĻāĻŋāϞā§
- Draw one ray parallel to the principal axis. After reflection, it appears to come from the principal focus (F).
- Draw another ray towards the centre of curvature (C). It reflects back along the same path. (Alternatively, a ray passing through the pole (P) may be drawn using the laws of reflection.)
- The reflected rays diverge, but their backward extensions meet behind the mirror between P and F.
- Therefore, the image is formed behind the mirror, between P and F.
- Nature of the image: i. Virtual, ii. Erect, iii. Diminished (smaller than the object)
āĻāϤā§āϤāϞ āĻĻāĻžāĻĒā§āύāϤ (Convex Mirror) āϝāĻŋāĻā§āύ⧠āϏāϏā§āĻŽ āĻĻā§ā§°āϤā§āĻŦāϤ āĻŦāϏā§āϤ⧠āĻĨāĻžāĻāĻŋāϞā§
- āĻāĻāĻž āĻāĻŋā§°āĻŖ āĻĒā§ā§°āϧāĻžāύ āĻ āĻā§āώ⧰ āϏāĻŽāĻžāύā§āϤ⧰āĻžāϞ āĻš'āϞā§, āĻĒā§ā§°āϤāĻŋāĻĢāϞāύ⧰ āĻĒāĻŋāĻāϤ āĻĒā§ā§°āϧāĻžāύ āĻĢ'āĻāĻžāĻ (F) ā§° āĻĒā§°āĻž āĻāĻšāĻŋāĻā§ āϝā§āύ āĻĻā§āĻāĻž āϝāĻžāϝāĻŧāĨ¤
- āĻāύ āĻāĻāĻž āĻāĻŋā§°āĻŖ āĻŦāĻā§ā§°āϤāĻžā§° āĻā§āύā§āĻĻā§ā§° (C) ā§° āĻĻāĻŋāĻļā§ āĻ'āϞā§, āϏā§āĻ āĻāĻā§ āĻĒāĻĨā§āĻĻāĻŋ āĻāĻāϤāĻŋ āĻāĻšā§āĨ¤ (āύāĻš'āϞ⧠āϧā§ā§°ā§ā§ąāĻŦāĻŋāύā§āĻĻā§ (P) āϤ āĻĒā§°āĻž āĻāĻŋā§°āĻŖ āĻāĻāύ āĻ āύā§āϏ⧰āĻŋ āĻ āĻāĻāύ āĻā§°āĻŋāĻŦ āĻĒāĻžā§°āĻŋāĨ¤)
- āĻĒā§ā§°āϤāĻŋāĻĢāϞāĻŋāϤ āĻāĻŋā§°āĻŖāϏāĻŽā§āĻš āĻŦāĻŋāĻā§āĻāĻŋāύā§āύ (diverge) āĻšāϝāĻŧ, āĻāĻŋāύā§āϤ⧠āϏāĻŋāĻšāĻāϤ⧰ āĻĒāĻŋāĻāĻĢāĻžāϞ⧰ āϏāĻŽā§āĻĒā§ā§°āϏāĻžā§°āĻŖ āĻĻāĻžāĻĒā§āύ⧰ āĻĒāĻŋāĻāĻĢāĻžāϞ⧠P āĻā§°ā§ F-ā§° āĻŽāĻžāĻāϤ āĻŽāĻŋāϞāĻŋāϤ āĻšāϝāĻŧāĨ¤
- āĻĢāϞāϤ, āĻĒā§ā§°āϤāĻŋāĻā§āĻāĻŦāĻŋ āĻĻāĻžāĻĒā§āύ⧰ āĻĒāĻŋāĻāĻĢāĻžāϞ⧠P āĻā§°ā§ F-ā§° āĻŽāĻžāĻāϤ āĻāĻ āύ āĻšāϝāĻŧāĨ¤
āĻĒā§ā§°āϤāĻŋāĻā§āĻāĻŦāĻŋā§° āĻŦā§āĻļāĻŋāώā§āĻā§āϝāĻ i. āĻ āĻŦāĻžāϏā§āĻ¤ā§ą (Virtual), ii. āĻĨāĻŋāϝāĻŧ (Erect), iii. āϏ⧰⧠(Diminished)
Note: Convex Mirror → Image is always formed between P and F, behind the mirror, and is always virtual, erect, and diminished.
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Convex Mirror (āĻāϤā§āϤāϞ āĻĻāĻžāĻĒā§āύ) – MCQs
1. The image formed by a convex mirror is always: āĻāϤā§āϤāϞ āĻĻāĻžāĻĒā§āύ⧠āϏāĻĻāĻžāϝāĻŧ āĻā§āύā§āϧ⧰āĻŖā§° āĻĒā§ā§°āϤāĻŋāĻā§āĻāĻŦāĻŋ āĻāĻ āύ āĻā§°ā§ ?
A) Real and inverted | B) Virtual, erect and diminished | C) Real and erect | D) Virtual and inverted
Ans: B) Virtual, erect and diminished
Explanation : A convex mirror always forms a virtual, erect, and diminished image for any position of the object. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻāϤā§āϤāϞ āĻĻāĻžāĻĒā§āύ⧠āϝāĻŋāĻā§āύ⧠āĻ ā§ąāϏā§āĻĨāĻžāϤ āĻ āĻŦāĻžāϏā§āĻ¤ā§ą, āĻĨāĻŋāϝāĻŧ āĻā§°ā§ āϏ⧰⧠āĻĒā§ā§°āϤāĻŋāĻā§āĻāĻŦāĻŋ āĻāĻ āύ āĻā§°ā§āĨ¤
2. In a convex mirror, the image is formed: āĻāϤā§āϤāϞ āĻĻāĻžāĻĒā§āύāϤ āĻĒā§ā§°āϤāĻŋāĻā§āĻāĻŦāĻŋ āĻ'āϤ āĻāĻ āĻŋāϤ āĻšāϝāĻŧ ?
A) Between F and C | B) At C | C) Between P and F behind the mirror | D) At infinity
Ans: C) Between P and F behind the mirror
Explanation : The reflected rays diverge, but their backward extensions meet between the Pole (P) and Focus (F) behind the mirror. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻĒā§ā§°āϤāĻŋāĻĢāϞāĻŋāϤ āĻāĻŋā§°āĻŖāϏāĻŽā§āĻšā§° āĻĒāĻŋāĻāĻĢāĻžāϞ⧰ āϏāĻŽā§āĻĒā§ā§°āϏāĻžā§°āĻŖ P āĻā§°ā§ F-ā§° āĻŽāĻžāĻāϤ āĻŽāĻŋāϞāĻŋāϤ āĻšāϝāĻŧāĨ¤ āϏā§āϝāĻŧā§āĻšā§ āĻĒā§ā§°āϤāĻŋāĻā§āĻāĻŦāĻŋ āĻĻāĻžāĻĒā§āύ⧰ āĻĒāĻŋāĻāĻĢāĻžāϞ⧠P āĻā§°ā§ F-ā§° āĻŽāĻžāĻāϤ āĻāĻ āύ āĻšāϝāĻŧāĨ¤
3. The principal focus of a convex mirror lies: āĻāϤā§āϤāϞ āĻĻāĻžāĻĒā§āύ⧰ āĻŽā§āĻā§āϝ āĻĢ'āĻāĻžāĻ āĻ'āϤ āĻ ā§ąāϏā§āĻĨāĻŋāϤ ?
A) In front of the mirror | B) Behind the mirror | C) At the pole | D) At infinity
Ans: B) Behind the mirror
Explanation : Since the reflected rays appear to come from a point behind the mirror, the principal focus lies behind the mirror. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻĒā§ā§°āϤāĻŋāĻĢāϞāĻŋāϤ āĻāĻŋā§°āĻŖāĻŦā§ā§° āĻĻāĻžāĻĒā§āύ⧰ āĻĒāĻŋāĻāĻĢāĻžāϞ⧰ āĻāĻāĻž āĻŦāĻŋāύā§āĻĻā§ā§° āĻĒā§°āĻž āĻāĻšāĻŋāĻā§ āϝā§āύ āĻĻā§āĻāĻž āϝāĻžāϝāĻŧāĨ¤ āϏā§āĻāĻŦāĻžāĻŦā§ āĻŽā§āĻā§āϝ āĻĢ'āĻāĻžāĻ āĻĻāĻžāĻĒā§āύ⧰ āĻĒāĻŋāĻāĻĢāĻžāϞ⧠āĻĨāĻžāĻā§āĨ¤
4. Which mirror is commonly used as a rear-view mirror in vehicles ?āϝāĻžāύāĻŦāĻžāĻšāύāϤ āĻĒāĻŋāĻāĻĢāĻžāϞ āĻāĻžāĻŦāϞ⧠āĻā§āύāĻā§ āĻĻāĻžāĻĒā§āύ āĻŦā§āĻ¯ā§ąāĻšāĻžā§° āĻā§°āĻž āĻšāϝāĻŧ ?
A) Plane mirror | B) Concave mirror | C) Convex mirror | D) Cylindrical mirror
Ans: C) Convex mirror
Explanation : A convex mirror provides a wide field of view, allowing the driver to see a larger area behind the vehicle. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻāϤā§āϤāϞ āĻĻāĻžāĻĒā§āύ⧠āĻŦā§āĻšā§ āĻĻā§āώā§āĻāĻŋāĻā§āώā§āϤā§ā§° āĻĒā§ā§°āĻĻāĻžāύ āĻā§°ā§, āϏā§āϝāĻŧā§āĻšā§ āĻāĻžāĻĄāĻŧā§ā§° āĻĒāĻŋāĻāĻĢāĻžāϞ⧰ āĻ āϧāĻŋāĻ āĻ āĻāĻļ āĻĻā§āĻāĻž āϝāĻžāϝāĻŧāĨ¤
5. The image formed by a convex mirror is: āĻāϤā§āϤāϞ āĻĻāĻžāĻĒā§āύāϤ āĻāĻ āĻŋāϤ āĻĒā§ā§°āϤāĻŋāĻā§āĻāĻŦāĻŋ āĻāĻŋāĻĻā§°ā§ āĻšāϝāĻŧ ?
A) Enlarged | B) Same size | C) Diminished | D) Highly magnified
Ans: C) Diminished
Explanation : The image formed by a convex mirror is always smaller than the object. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻāϤā§āϤāϞ āĻĻāĻžāĻĒā§āύ⧠āĻāĻ āύ āĻā§°āĻž āĻĒā§ā§°āϤāĻŋāĻā§āĻāĻŦāĻŋ āϏāĻĻāĻžāϝāĻŧ āĻŦāϏā§āϤā§āϤāĻā§ āϏ⧰⧠āĻšāϝāĻŧāĨ¤
6. Which ray rule is correct for a convex mirror ? āĻāϤā§āϤāϞ āĻĻāĻžāĻĒā§āύ⧰ āĻŦāĻžāĻŦā§ āĻā§āύāĻā§ āĻāĻŋā§°āĻŖ āύāĻŋāϝāĻŧāĻŽ āϏāĻ āĻŋāĻ ?
A) A ray parallel to the principal axis passes through F after reflection. | B) A ray parallel to the principal axis appears to come from F after reflection. | C) A ray through F becomes parallel after reflection. | D) A ray through C never reflects.
Ans: B) A ray parallel to the principal axis appears to come from F after reflection.
Explanation : In a convex mirror, a ray parallel to the principal axis is reflected in such a way that it appears to originate from the principal focus (F). āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻĒā§ā§°āϧāĻžāύ āĻ āĻā§āώ⧰ āϏāĻŽāĻžāύā§āϤ⧰āĻžāϞ āĻāĻŋā§°āĻŖ āĻĒā§ā§°āϤāĻŋāĻĢāϞāύ⧰ āĻĒāĻŋāĻāϤ āĻŽā§āĻā§āϝ āĻĢ'āĻāĻžāĻ (F)-ā§° āĻĒā§°āĻž āĻāĻšāĻŋāĻā§ āϝā§āύ āĻĻā§āĻāĻž āϝāĻžāϝāĻŧāĨ¤
7. The image formed by a convex mirror is always: āĻāϤā§āϤāϞ āĻĻāĻžāĻĒā§āύāϤ āĻāĻ āĻŋāϤ āĻĒā§ā§°āϤāĻŋāĻā§āĻāĻŦāĻŋ āϏāĻĻāĻžāϝāĻŧ āĻā§āύ⧠āĻšāϝāĻŧ ?
A) Real | B) Virtual | C) Inverted | D) Magnified
Ans: B) Virtual
Explanation : The reflected rays do not actually meet; only their backward extensions meet. Hence the image is virtual. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻĒā§ā§°āϤāĻŋāĻĢāϞāĻŋāϤ āĻāĻŋā§°āĻŖāĻŦā§ā§° āĻŦāĻžāϏā§āĻ¤ā§ąāϤ⧠āĻŽāĻŋāϞāĻŋāϤ āύāĻšāϝāĻŧ; āĻā§ā§ąāϞ āĻĒāĻŋāĻāĻĢāĻžāϞ⧰ āϏāĻŽā§āĻĒā§ā§°āϏāĻžā§°āĻŖ āĻŽāĻŋāϞāĻŋāϤ āĻšāϝāĻŧāĨ¤ āϏā§āϝāĻŧā§āĻšā§ āĻĒā§ā§°āϤāĻŋāĻā§āĻāĻŦāĻŋ āĻ āĻŦāĻžāϏā§āĻ¤ā§ą āĻšāϝāĻŧāĨ¤
8. A convex mirror provides: āĻāϤā§āϤāϞ āĻĻāĻžāĻĒā§āύ⧠āĻāĻŋ āϏā§āĻŦāĻŋāϧāĻž āĻĻāĻŋāϝāĻŧā§ ?
A) Small field of view | B) Wide field of view | C) No field of view | D) Only magnified images
Ans: B) Wide field of view
Explanation : A convex mirror covers a larger area, making it ideal for rear-view mirrors in vehicles. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻāϤā§āϤāϞ āĻĻāĻžāĻĒā§āύ⧠āĻ āϧāĻŋāĻ āĻāϞā§āĻāĻž āĻĻā§āĻā§ā§ąāĻžāϝāĻŧ, āϏā§āϝāĻŧā§āĻšā§ āĻ āĻāĻžāĻĄāĻŧā§ā§° rear-view mirror āĻšāĻŋāĻāĻžāĻĒā§ āĻŦā§āĻ¯ā§ąāĻšāĻžā§° āĻā§°āĻž āĻšāϝāĻŧāĨ¤
Trick : Convex Mirror → VED + PF
- V = Virtual (āĻ āĻŦāĻžāϏā§āĻ¤ā§ą)
- E = Erect (āĻĨāĻŋāϝāĻŧ)
- D = Diminished (āϏ⧰ā§)
- PF = Image forms between Pole (P) and Focus (F) behind the mirror.