StudyTunnel Logo
StudyTunnel
by BhamuIntelli Systems LLP

Home

School

CBSE

Class 10

Science

Light – Reflection and Refraction

Light – Reflection and Refraction

Action PlanNotesQuestionsMock-Test
Study Action Plan (Sorted by Difficulty)
Spherical Mirror Terminology and Sign Convention
Accuracy: 55%
Total Attempted620
Total Correct341
Total Incorrect279
Difficulty Level:
Medium
Power of a Lens
Accuracy: 55%
Total Attempted608
Total Correct336
Total Incorrect272
Difficulty Level:
Medium
Refraction of Light
Accuracy: 69%
Total Attempted969
Total Correct673
Total Incorrect296
Difficulty Level:
Medium
Image Formation by Lenses
Accuracy: 70%
Total Attempted390
Total Correct273
Total Incorrect117
Difficulty Level:
Medium
Mirror and Lens Formulas
Accuracy: 71%
Total Attempted948
Total Correct677
Total Incorrect271
Difficulty Level:
Medium
Spherical Lens Terminology and Sign Convention
Accuracy: 76%
Total Attempted29
Total Correct22
Total Incorrect7
Difficulty Level:
Low
Reflection of Light by Spherical Mirrors
Accuracy: 76%
Total Attempted733
Total Correct557
Total Incorrect176
Difficulty Level:
Low
Refraction through Rectangular Glass Slab
Accuracy: 76%
Total Attempted383
Total Correct292
Total Incorrect91
Difficulty Level:
Low
Refractive Index and Optical Density
Accuracy: 87%
Total Attempted320
Total Correct277
Total Incorrect43
Difficulty Level:
Low

Learning Objectives

Top

Learning Objectives

  • Understand the reflection of light by spherical mirrors, including concave and convex mirrors, using laws of reflection and ray diagrams.
  • Calculate image formation by spherical mirrors using the mirror formula and sign conventions.
  • Analyze the refraction of light as it passes through different media, governed by Snell's Law and refractive indices.
  • Apply the lens formula to determine the relationship between object distance, image distance, and focal length for convex and concave lenses.
  • Explore the power of a lens as the reciprocal of its focal length and its applications in optical instruments.
  • Examine the refractive index and optical density as measures of how much light slows down in a medium compared to vacuum.
  • Investigate the terminology and sign conventions for spherical mirrors, including pole, center of curvature, radius of curvature, principal axis, and focal length.
  • Study the refraction through a rectangular glass slab, including lateral displacement and the emergent ray parallel to the incident ray.
  • Understand spherical lens terminology and sign conventions, including optical center, centers of curvature, principal axis, and principal foci.

Practice, Analyze & Improve

Dont just read—test your knowledge! Unlock the Student Workspace to take chapter tests and get instant performance insights.

Deep Analytics

Peer Comparison

Track Progress

Claim Free Account100% Free • No credit card required

Revision Notes & Summary

Top

Chapter Notes

Reflection of Light by Spherical Mirrors

  • Laws of Reflection:
    • The angle of incidence is equal to the angle of reflection.
    • The incident ray, the normal to the mirror at the point of incidence, and the reflected ray all lie in the same plane.
  • Spherical Mirrors:
    • Concave Mirror: Reflecting surface curved inwards.
    • Convex Mirror: Reflecting surface curved outwards.
  • Key Terms:
    • Pole (P): Center of the mirror's surface.
    • Centre of Curvature (C): Center of the sphere from which the mirror is a part.
    • Principal Axis: Line passing through P and C.
    • Principal Focus (F): Point where parallel rays converge or appear to diverge.
    • Focal Length (f): Distance between P and F.
  • Image Formation by Concave Mirror:
    • Table:
      Position of ObjectPosition of ImageSize of ImageNature of Image
      At infinityAt focus FHighly diminished, point-sizedReal and inverted
      Beyond CBetween F and CDiminishedReal and inverted
      At CAt CSame sizeReal and inverted
      Between C and FBeyond CEnlargedReal and inverted
      At FAt infinityImage not formed
      Between P and FBehind the mirrorEnlargedVirtual and erect

Refraction of Light

  • Snell's Law:
    • sin⁡isin⁡r=constant\frac{\sin i}{\sin r} = \text{constant}
  • Refractive Index:
    • Ratio of speed of light in vacuum to that in the medium.
    • Table of Refractive Indices:
      MaterialRefractive Index
      Air1.0003
      Water1.33
      Glass1.52
      Diamond2.42
  • Refraction through Rectangular Glass Slab:
    • Incident ray, refracted ray, and emergent ray are parallel.
    • Lateral shift occurs.

Image Formation by Lenses

  • Convex Lens: Converges light rays.
  • Concave Lens: Diverges light rays.
  • Image Formation by Convex Lens:
    • Table:
      Position of ObjectPosition of ImageRelative SizeNature
      At infinityAt focus F2Highly diminishedReal and inverted
      Beyond 2F1Between F2 and 2F2DiminishedReal and inverted
      At 2F1At 2F2Same sizeReal and inverted
      Between F1 and 2F1Beyond 2F2EnlargedReal and inverted
      At F1At infinityImage not formed
      Between F1 and OOn the same sideEnlargedVirtual and erect
  • Image Formation by Concave Lens:
    • Table:
      Position of ObjectPosition of ImageRelative SizeNature
      At infinityAt focus F1Highly diminishedVirtual and erect
      Between infinity and OBetween F1 and ODiminishedVirtual and erect

Mirror and Lens Formulas

  • Mirror Formula: 1v+1u=1f\frac{1}{v} + \frac{1}{u} = \frac{1}{f}
  • Lens Formula: 1v−1u=1f\frac{1}{v} - \frac{1}{u} = \frac{1}{f}
  • Magnification: m=h′h=vum = \frac{h'}{h} = \frac{v}{u}

Power of a Lens

  • Definition: Power (PP) is the reciprocal of the focal length (ff).
  • Formula: P=1fP = \frac{1}{f}
  • Unit: Dioptre (D), where 1D=1m−11D = 1m^{-1}.
  • Sign Convention: Positive for convex lenses, negative for concave lenses.

Refractive Index and Optical Density

  • Optical Density: Related to the refractive index; higher refractive index means optically denser medium.
  • Speed of Light: Faster in rarer medium, slower in denser medium.
Do you belong in the Top 10%?

Our analytics show that most students struggle with specific concepts in Light – Reflection and Refraction. Take a free diagnostic test to generate your personal Learning DNA profile.

Practice Test – MCQs, True/False

Top

Multiple Choice Questions

A.

The image is virtual and erect.

B.

The image is real and inverted.

C.

The image is virtual and smaller.

D.

The image is real and larger.
Correct Answer: B

Solution:

When an object is placed at the center of curvature of a concave mirror, the image formed is real, inverted, and of the same size as the object.

Chapter Concept:

Image Formation by Lenses

A.

At 30 cm, real and inverted

B.

At 40 cm, virtual and erect

C.

At 30 cm, virtual and erect

D.

At 40 cm, real and inverted
Correct Answer: A

Solution:

Using the mirror formula 1v+1u=1f\frac{1}{v} + \frac{1}{u} = \frac{1}{f}, with u=−60u = -60 cm and f=−20f = -20 cm, we find v=−30v = -30 cm. The image is real and inverted.

Chapter Concept:

Refraction of Light

A.

At the center of curvature

B.

Beyond the center of curvature

C.

At the principal focus

D.

Between the pole and the principal focus
Correct Answer: D

Solution:

A concave mirror forms a virtual, erect, and enlarged image when the object is placed between the pole and the principal focus.

Chapter Concept:

Reflection of Light by Spherical Mirrors

A.

Approximately 19.5∘19.5^\circ

B.

Approximately 22.0∘22.0^\circ

C.

Approximately 25.0∘25.0^\circ

D.

Approximately 28.0∘28.0^\circ
Correct Answer: A

Solution:

Using Snell's Law: n1sin⁡i=n2sin⁡rn_1 \sin i = n_2 \sin r, where n1=1n_1 = 1 (air), n2=1.5n_2 = 1.5, and i=30∘i = 30^\circ. Solving for rr, sin⁡r=11.5×sin⁡30∘=11.5×0.5=0.333\sin r = \frac{1}{1.5} \times \sin 30^\circ = \frac{1}{1.5} \times 0.5 = 0.333. Thus, r≈19.5∘r \approx 19.5^\circ.

Chapter Concept:

Refractive Index and Optical Density

A.

The point where parallel rays converge after reflection.

B.

The point where parallel rays appear to diverge after reflection.

C.

The center of curvature of the mirror.

D.

The point on the mirror's surface where the incident ray strikes.
Correct Answer: A

Solution:

The principal focus of a concave mirror is the point where rays parallel to the principal axis converge after reflection.

Chapter Concept:

Reflection of Light by Spherical Mirrors

A.

2 dioptres

B.

0.5 dioptres

C.

1 dioptre

D.

0.2 dioptres
Correct Answer: A

Solution:

The power of a lens is the reciprocal of its focal length. Thus, P=1f=10.5=2P = \frac{1}{f} = \frac{1}{0.5} = 2 dioptres.

Chapter Concept:

Power of a Lens

A.

Both are concave.

B.

Both are convex.

C.

The mirror is concave, and the lens is convex.

D.

The mirror is convex, and the lens is concave.
Correct Answer: A

Solution:

A negative focal length indicates that both the mirror and the lens are concave, as concave mirrors and lenses have negative focal lengths.

Chapter Concept:

Spherical Mirror Terminology and Sign Convention

A.

1.5

B.

1.33

C.

1.25

D.

1.0
Correct Answer: C

Solution:

The refractive index nn is given by the formula n=cvn = \frac{c}{v}, where cc is the speed of light in vacuum and vv is the speed of light in the medium. Thus, n=3×1082×108=1.5n = \frac{3 \times 10^8}{2 \times 10^8} = 1.5.

Chapter Concept:

Refractive Index and Optical Density

A.

The emergent ray is parallel to the incident ray.

B.

The emergent ray is perpendicular to the incident ray.

C.

The emergent ray is at an angle to the incident ray.

D.

The emergent ray retraces the path of the incident ray.
Correct Answer: A

Solution:

In a rectangular glass slab, the emergent ray is parallel to the incident ray due to equal and opposite bending at the two interfaces.

Chapter Concept:

Refraction through Rectangular Glass Slab

A.

Concave mirror

B.

Convex mirror

C.

Plane mirror

D.

None of the above
Correct Answer: A

Solution:

A concave mirror can produce an erect and enlarged image when the object is placed between the pole and the principal focus.

Chapter Concept:

Reflection of Light by Spherical Mirrors

Experience the StudyTunnel Method

We do not just give you mock tests. We guide you through a gamified, AI-driven learning path designed to guarantee mastery.

Step 1: Practicing the Concepts

Light – Reflection and Refraction

Step 2: Master Boss Exam
Locked • Full Phase Assessment
Step 3: Redemption Arena
Locked • AI Weakness Tracker

True or False

Correct Answer: False

Solution:

The correct mirror formula is 1v+1u=1f\frac{1}{v} + \frac{1}{u} = \frac{1}{f}, but the correct signs must be used according to the New Cartesian Sign Convention.

Chapter Concept :

Mirror and Lens Formulas

Correct Answer: True

Solution:

For spherical mirrors of small apertures, the radius of curvature RR is found to be equal to twice the focal length ff. Therefore, f=R2f = \frac{R}{2}.

Chapter Concept :

Spherical Lens Terminology and Sign Convention

Correct Answer: True

Solution:

For a concave mirror, the principal focus is indeed on the same side as the object, as the reflected rays converge at this point.

Chapter Concept :

Reflection of Light by Spherical Mirrors

Correct Answer: False

Solution:

The focal length of a convex lens is positive, and it converges light rays to a point on the principal axis.

Chapter Concept :

Image Formation by Lenses

Correct Answer: True

Solution:

A concave lens diverges light rays, causing the image to be virtual, erect, and diminished for all object positions.

Chapter Concept :

Image Formation by Lenses

Correct Answer: False

Solution:

The focal length of a spherical mirror is half the radius of curvature, given by f=R2f = \frac{R}{2}.

Chapter Concept :

Mirror and Lens Formulas

Correct Answer: True

Solution:

Refraction is the bending of light as it passes from one medium to another due to a change in speed.

Chapter Concept :

Refraction of Light

Correct Answer: False

Solution:

The focal length of a convex lens is positive because it converges light rays.

Chapter Concept :

Image Formation by Lenses

Correct Answer: True

Solution:

A concave lens diverges light rays and always forms a virtual, erect, and diminished image, regardless of the object's position.

Chapter Concept :

Image Formation by Lenses

Correct Answer: False

Solution:

According to the New Cartesian sign convention, distances measured to the left of the mirror are considered negative.

Chapter Concept :

Spherical Mirror Terminology and Sign Convention

AI Learning Assistant
Top

I can help you understand Light – Reflection and Refraction better. Ask me anything!

Summarize the main points of Light – Reflection and Refraction.
What are the most important terms to remember here?
Explain this concept like I'm five.
Give me a quick 3-question practice quiz.
StudyTunnel Methodology

We dont just provide random mock tests. Our AI-driven, phase-wise learning system is designed to guarantee mastery from your first chapter to your final exam.

1
Master the Concepts

Start with chapter notes, formulas, and common exam mistakes. Practice with thousands of MCQs, True/False, and Descriptive questions with instant solutions.

2
Conquer Boss Exams

Once you master individual chapters, unlock Phase-wise Boss Exams. These milestone tests simulate the actual exam environment to test your retention across multiple subjects.

3
The Redemption Arena

The ultimate learning hack. Our AI tracks every mistake you make and dynamically generates custom tests targeting your weak points until you achieve 100% accuracy.