Light (Class 8 Science)
Explore the properties of light, reflection, refraction, and the human eye. Understand how light enables vision and interacts with different materials.
TL;DR: Explore the properties of light, reflection, refraction, and the human eye. Understand how light enables vision and interacts with different materials…
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Explore the properties of light, reflection, refraction, and the human eye. Understand how light enables vision and interacts with different materials.
Light MCQs with Answers & Explanations
Q1. What is light?
- Mechanical waves
- Sound waves
- Thermal energy
- Electromagnetic radiation ✓ (correct)
Explanation: Light is electromagnetic radiation that can travel through space and matter. It exhibits properties of both waves and particles.
Q2. What is the speed of light in vacuum?
- 300,000 km/s ✓ (correct)
- 100,000 km/s
- 1000 m/s
- 340 m/s
Explanation: The speed of light in vacuum is approximately 300,000 km/s or 3 x 10^8 m/s. This is the fastest speed in the universe.
Q3. What is reflection of light?
- Bending of light
- Bouncing back of light from a surface ✓ (correct)
- Passing through a material
- Absorption of light
Explanation: Reflection is the bouncing back of light when it hits a surface. The law of reflection states that the angle of incidence equals the angle of reflection.
Q4. What is refraction of light?
- Bouncing of light
- Absorption of light
- Bending of light when passing from one medium to another ✓ (correct)
- Scattering of light
Explanation: Refraction is the bending of light when it passes from one medium to another with different densities. It occurs due to change in light speed.
Q5. What is the function of the cornea in the eye?
- Focusing light onto retina
- Controlling light entry
- Detecting light
- Refracting light ✓ (correct)
Explanation: The cornea is the transparent front part of the eye that refracts (bends) light rays. It provides most of the refracting power of the eye.
Q6. What is the function of the iris in the eye?
- Controlling the amount of light entering the eye ✓ (correct)
- Detecting light
- Refracting light
- Transmitting signals
Explanation: The iris is the colored part of the eye that controls the size of the pupil, regulating the amount of light that enters the eye.
Q7. What is the function of the retina?
- Refracting light
- Converting light into electrical signals ✓ (correct)
- Controlling light entry
- Adjusting lens shape
Explanation: The retina is the light-sensitive tissue at the back of the eye containing photoreceptors that convert light into electrical signals sent to the brain.
Q8. What colors make up white light?
- Only secondary colors
- Only primary colors
- All colors of the visible spectrum ✓ (correct)
- Red and blue
Explanation: White light is composed of all colors of the visible spectrum: red, orange, yellow, green, blue, indigo, and violet (ROYGBIV).
Q9. What is dispersion of light?
- Absorption of light
- Bouncing of light
- Bending of light
- Splitting of white light into different colors ✓ (correct)
Explanation: Dispersion is the splitting of white light into its constituent colors when it passes through a prism. Different colors bend at different angles.
Q10. What is a convex lens?
- Thicker in center and converges light ✓ (correct)
- Flat lens
- Concave on both sides
- Thinner in center
Explanation: A convex lens is thicker in the center and thinner at the edges. It converges light rays and is used in magnifying glasses and cameras.
Frequently Asked Questions
How does the human eye see objects?
Light reflects from objects and enters the eye through the cornea and pupil. The lens focuses this light onto the retina, where photoreceptors convert it into electrical signals. The brain interprets these signals as images.
Why do different materials have different colors?
Objects appear colored because they absorb certain colors of light and reflect others. A red apple absorbs all colors except red, which it reflects to our eyes.
More Class 8 Science MCQs
- Light Reflection and Refraction
- Electricity
- Acids Bases and Salts
- Life Processes
- Carbon and its Compounds
- Metals and Non-metals
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