Case Study:

Riya noticed that whenever she entered a shopping mall elevator, she appeared slightly taller and slimmer in the mirror fixed on one wall. Her friend Aarav observed the same effect in another elevator. According to NCERT, a plane mirror forms an image that is virtual, erect, and of the same size as the object. Then why did the reflection appear different?

If you’ve ever wondered about the physics behind this, you can dive deeper into how mirrors and lenses work: understanding reflection and refraction to see why light behaves this way.

To investigate this, the students observed three elevators in different buildings. In Elevator A, the mirror covered the entire wall from floor to ceiling. In Elevator B, the mirror was slightly curved due to poor installation. In Elevator C, bright lights were fixed above the mirror, and the mirror was tilted backward by a small angle. The students also measured that they stood approximately 1 metre away from the mirror in each case.

This visual distortion is similar to why objects appear bent in water, where light bending creates a shift in our perception

Their physics teacher explained that according to the Laws of Reflection of Light, the angle of incidence is equal to the angle of reflection. A properly installed plane mirror forms an image identical in size to the object. However, slight curvature, tilt, lighting effects, and viewing angles can create an illusion that changes how the brain perceives height and body shape, even though the laws of reflection are still followed.

Understanding the difference between real vs. virtual images is key to mastering how different mirrors and lenses affect our daily vision.

CASE-BASED QUESTIONS

 MCQ 

Q1. Which property of a plane mirror remains correct even in an elevator mirror?

A. It forms a real image
B. It forms a diminished image
C. It forms a virtual image of same size
D. It forms an inverted image

Q2. In which elevator is the image most likely to appear distorted?

A. Elevator A
B. Elevator B
C. Elevator C
D. All elevators equally

 Assertion - Reason 

Q3. Assertion (A): A properly installed plane mirror forms an image of the same height as the object.
Reason (R): According to the Laws of Reflection of Light, reflected rays always meet behind the mirror.

Options:
A. Both A and R are true, and R is the correct explanation of A
B. Both A and R are true, but R is not the correct explanation of A
C. A is true, but R is false
D. A is false, but R is true

 Application-Based 

Q4. Can a tilted mirror inside an elevator create the illusion that a person looks taller even if it is a plane mirror?

Q5. A student stands 1.5 m in front of a plane mirror inside an elevator. What is the distance between the student and the image formed?

 Data/Logic-Based 

Q6. The students observed the following:

Based on the observations, which factor mainly affects the unusual appearance in elevators?

A. Change in Laws of Reflection
B. Human perception and mirror positioning
C. Formation of real image
D. Increase in speed of light

ANSWER KEY WITH EXPLANATION

A1. C: It forms a virtual image of same size
 Explanation:  A plane mirror always forms a virtual, erect image of the same size as the object according to NCERT principles of Image Formation by Plane Mirror.

A2. B: Elevator B
 Explanation:  A slightly curved mirror does not behave exactly like a plane mirror and can stretch or compress the image, causing distortion.

A3. B: Both A and R are true, but R is not the correct explanation of A
 Explanation:  Both statements are true. Plane mirrors form same-sized images, and reflected rays appear to meet behind the mirror. However, this does not directly explain equal image size.

A4. When the mirror is tilted, the viewing angle changes. The brain interprets body proportions differently, creating a visual illusion of increased height although the mirror still obeys the Laws of Reflection of Light.

A5. Distance between student and image = 3 m
 Explanation:  In a plane mirror, image distance equals object distance.
Object distance = 1.5 m
Image distance behind mirror = 1.5 m
Total separation = 1.5 + 1.5 = 3 m

A6. B: 

 Explanation:  The unusual appearance mainly occurs due to mirror tilt, slight curvature, lighting, and human visual perception - not because the laws of reflection change.

Ready to ace your Physics exams? Boost your confidence by practicing with our Class 10 Physics Worksheets. Once you're comfortable, try testing your skills with an unsolved practice paper or review the step-by-step logic in our solved practice papers.

HOTS EXTENSION QUESTIONS 

Q1. Suppose Elevator B replaces its slightly curved mirror with a perfectly plane mirror but keeps the same lighting arrangement. Will people still feel they look different? Explain scientifically.

Q2. Why do clothing stores sometimes use special mirror arrangements and lighting to make customers appear taller or slimmer? Which concepts of light are involved?

These same principles of light manipulation are what allow optical instruments like microscopes and telescopes to magnify and clarify images beyond the naked eye.

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