Class 10 Physics Worksheet The Human Eye and the Colorful World

The human eye is a natural optical instrument that helps us see the world around us. It works like a camera, capturing light and forming images. Let’s look at the main parts of the eye and their functions:

1. Cornea: The transparent, curved front layer of the eye that refracts most of the light entering the eye.
2. Iris: The colored part of the eye that controls the size of the pupil, regulating the amount of light entering the eye.
3. Pupil: The small opening in the iris through which light enters the eye.
4. Lens: A flexible, transparent structure that changes its shape to focus light onto the retina.
5. Retina: The inner lining of the eye that contains light-sensitive cells (rods and cones). It converts light into electrical signals.
6. Optic Nerve: The nerve that carries electrical signals from the retina to the brain.

The ability to see depends on how light is focused on the retina and interpreted by the brain.

Do Check: CBSE Class 10 Science Chapter 11 The Human Eye and the Colourful World Notes

Working of the Eye

When light enters the eye, it passes through the cornea, the pupil, and the lens. The lens focuses this light onto the retina, where an inverted image is formed. The retina’s cells convert the light into electrical signals, which are sent to the brain via the optic nerve. The brain then processes these signals, and we perceive the image as upright.

Defects of Vision and Their Correction

The human eye can experience several vision problems due to various reasons. Here are some common defects and how they are corrected:

1. Myopia (Nearsightedness):
   • Cause: The eye’s lens focuses light in front of the retina.
   • Symptom: Difficulty seeing distant objects clearly.
   • Correction: Use of concave lenses.
2. Hypermetropia (Farsightedness):
   • Cause: The eye’s lens focuses light behind the retina.
   • Symptom: Difficulty seeing nearby objects clearly.
   • Correction: Use of convex lenses.
3. Presbyopia:
   • Cause: Loss of flexibility in the lens due to aging.
   • Symptom: Difficulty focusing on both nearby and distant objects.
   • Correction: Use of bifocal lenses.
4. Astigmatism:
   • Cause: Irregular curvature of the cornea or lens.
   • Symptom: Blurred or distorted vision.
   • Correction: Use of cylindrical lenses.

The Colorful World

Light is the reason we see colors. When light passes through a prism, it splits into seven colors: red, orange, yellow, green, blue, indigo, and violet. This phenomenon is called dispersion.

Phenomena Related to Light and Colors

1. Refraction:
   • Refraction occurs when light passes from one medium to another and bends due to a change in speed.
   • Example: A pencil appears bent when placed in a glass of water.
2. Dispersion:
   • Dispersion is the splitting of white light into its component colors.
   • Example: The formation of a rainbow.
3. Scattering of Light:
   • Scattering occurs when light interacts with particles in the atmosphere.
   • Example: The sky appears blue because blue light is scattered more than other colors.
4. Tyndall Effect:
   • The scattering of light by particles in a colloid.
   • Example: Beams of sunlight visible through a forest.

Class 10 Worksheet The Human Eye and the Colorful World

Worksheet 1: Match the following

Worksheet 2: Multiple Choice Questions (MCQs)

1. Which part of the eye controls the amount of light entering it?
   a) Retina
   b) Lens
   c) Cornea
   d) Iris
2. Myopia is also known as:
   a) Farsightedness
   b) Nearsightedness
   c) Astigmatism
   d) Presbyopia
3. What phenomenon causes the formation of a rainbow?
   a) Refraction only
   b) Reflection and refraction
   c) Dispersion of light
   d) Scattering of light
4. The power of a lens is -2.0 D. What type of lens is it?
   a) Convex
   b) Concave
   c) Cylindrical
   d) Bifocal
5. Why does the sky appear blue?
   a) Reflection of light
   b) Dispersion of light
   c) Scattering of shorter wavelengths
   d) Absorption of blue light by the atmosphere

Worksheet 3: Label the Diagram

1. Draw a labeled diagram of the human eye. Include the following parts:
   • Cornea
   • Iris
   • Pupil
   • Lens
   • Retina
   • Optic nerve
2. Draw and label the following:
   • Dispersion of light through a prism.
   • Formation of a rainbow.

Worksheet 4: Fill in the Blanks (Advanced)

1. The defect of the eye where a person cannot see nearby objects clearly is called _______.
2. The phenomenon of _______ causes the splitting of white light into seven colors.
3. The _______ controls the size of the pupil based on the intensity of light.
4. The minimum distance at which the eye can see objects clearly is called the _______.
5. In a rainbow, the outermost color is _______ and the innermost color is _______.

Worksheet 5: Assertion and Reasoning

1. Assertion: Myopia can be corrected using concave lenses.
   Reason: Concave lenses help in converging the light rays before they reach the retina.
   a) Both Assertion and Reason are true, and Reason is the correct explanation.
   b) Both Assertion and Reason are true, but Reason is not the correct explanation.
   c) Assertion is true, but Reason is false.
   d) Both Assertion and Reason are false.
2. Assertion: A rainbow is formed due to scattering of light in the atmosphere.
   Reason: Scattering occurs when light passes through raindrops, splitting into seven colors.
   a) Both Assertion and Reason are true, and Reason is the correct explanation.
   b) Both Assertion and Reason are true, but Reason is not the correct explanation.
   c) Assertion is true, but Reason is false.
   d) Both Assertion and Reason are false.

Worksheet 6: Descriptive Questions

1. Describe the process of accommodation in the human eye.
2. What are the three main reasons for the formation of a rainbow? Explain each step briefly.
3. Differentiate between the Tyndall Effect and scattering of light.
4. Explain why the sun appears red during sunrise and sunset.
5. What happens to the focal length of the eye lens when you shift your focus from a distant object to a nearby one?

Worksheet 7: Numerical Problems

1. A convex lens has a focal length of 20 cm. Calculate its power.
   Formula: Power (P) = 100 / Focal Length (F in cm)
2. The focal length of a concave lens is -50 cm. What is the power of the lens?
3. A ray of light passes from air into glass at an angle of incidence of 45°. The refractive index of glass is 1.5. Calculate the angle of refraction using Snell’s law.
4. A person uses a bifocal lens to correct their vision. The upper part of the lens has a power of +2.0 D and the lower part has a power of -1.0 D. What do these powers indicate about the person’s vision?
5. An object is placed 30 cm from a concave lens with a focal length of -15 cm. Calculate the position and nature of the image using the lens formula:
   
   $\frac{1}{f}=\frac{1}{v}-\frac{1}{u}$

    

Worksheet 8: Experiment-Based Questions

1. In a dark room, shine a flashlight through a glass prism.
   • What do you observe?
   • Explain why the light splits into different colors.
2. Take a glass of water and place a pencil in it.
   • How does the pencil appear?
   • Which phenomenon is responsible for this?
3. Perform an experiment using a torch and a CD. Shine the torchlight on the CD at different angles.
   • What do you observe?
   • Relate this to the concept of dispersion.

Worksheet 9: Higher-Order Thinking Skills (HOTS)

1. Why can’t we see clearly underwater without wearing goggles?
2. A person’s eyes are unable to adjust while reading a book. What could be the reason for this, and how can it be corrected?
3. If white light is passed through a prism followed by another inverted prism, what would be the outcome? Explain.
4. Explain why astronauts in space do not see a blue sky like we do on Earth.
5. During foggy weather, car headlights appear to scatter more light. Explain the phenomenon behind this observation.