light and vision

Part - A

Q1. What Happens To The Rays Of Light In case Of Diffuse Reflection?

Ans. In Case Of Diffuse Reflection, The Rays Of A Beam Are Reflected In Different Directions.

Q2. An Object Placed 10 Cm Infront Of A Plane Mirror. Where Is The Image Formed? How Far Is It From The Mirror? 

Ans. Image Is Formed Behind The Mirror At 10 Cm From Mirror.

Q3. How Many Images Are Formed When Object Placed Between Two Mirrors That Are Right Angle To Each Other.

Ans. No. Of Images 

360° / Angle Between Two Mirror -1

= 360 /90 =-1

= 4-1=3.

Q4. What Is White Light? Give Example.

Ans. The Colourless Light Formed By Mixing Of All The Colours Is Called White Light 

For Example. Sunlight.

Q5 Define Dispersion?

Ans. The Splitting Of White Light Into Its Component Colours By Refraction Is Called Dispersion Of Light.

Q6. Which Parts Of Eyes Make Up Its Converging Lens System? 

Ans. Cornea, Lens And Fluids Make Up Converging Lens System.

Q7. A Person Has Myopia. What Problem Does He Face?

Ans. The Person Can See Near Object Clearly But Not Able To See Far Objects Clearly.

Q8. What Is the First Stage Of Nutritional Blindness?

Ans. The Person Is Not Able To See In Dim 

Light Or In Night.

Part-b

Q1:A Shiny Metal Utensils Forms An Image But The Image Is Not As Clear As That Formed By A Mirror Why?

Ans. Because Utensil Have Rough Surface. There Is Diffuse Reflection Of Light Occurs. It Will Form A Blur Image.

Q2. State Laws Of Reflection Of Light? 

Ans. 1.The Angle Of Incident Is Equal To Angle Of Reflection.

2. The Incident Ray, Reflected Ray And Normal Lies In the Same Surface.

Q3. Write Properties Of Image Formed By A Plane Mirror?

Ans.  1.  Image Is Erect.

2. Image Is Virtual.

3. Image Is Literally Inverted.

4.Image Is Of the Same Size As That Of Object.

5. Image Is At The Same Distance From Mirror As Your Object.

Q4. What Is Lateral Inversion?

Ans. In The Plane Mirror, Left Hand And The Right Hand Side Gets Reversed, It Is Called Lateral Inversion.

 

Q5. How Is The Light Entering The Eye Controlled?

Ans. The Light Entering The Eye Is Controlled By Iris. In The Dim Light (Less Light), Size Of The Iris Will Increases And Allows The More Light To Enter Inside, And Vice-versa.

Q6. What Do You Understand By Blind Spot Of The Eye? 

Ans. It Is A Point Inside The Eye, Where No Sense  Recovers Are Present. The Message Of Image Formed On This Point, Will Not S End To The Brain. This Is Point Called Blind Spot.

Q7. What Is Accommodation? How Is It Achieved In The Human Eye?

Ans: It Is A Process In Which the Focal Length  Of The Eye Land Is Changes To Form The Clear Image Of All The For Object In The Brain. It Is Achieved In The Human Eye By Ciliary Muscles.

Q8. What Is Braille? 

Ans. Braille Is A System Of Showing The Different Letters By Raised Dots. Each Combination Represent The Different Letter.

Part -c

Q2. Describe The Structure Of Eye With The Help Of Diagram?

Ans. 1.  Sclera. It Is A White Colour Membrane Of Eyeball. It Gives Protection To Eye Ball.

2. Cornea. The Small Bulge Transparent Membrane Is Called Cornea.

3. Iris. The Colour Disc Shaped Structure Of Eye Is Called Iris.

4. Eye Lens. Each Eye Has  One Flexible Convex Lens. It Form Image On Retina.

5. Aqueous Humour. The Water Like Liquid Present Between Cornea And Lens Is Called Aquos Humour.

6. Pupil. A Small Opening Window Of Eye Is Called Pupil.

7.Vitreous Humour. A Jelly Like Liquid Filled Between Lens And Retina.

8. Retina. The Image Is Formed On The Retina. It Is Present At The Base Of The 

Eyeball.

9. Cillary Muscles. Lt  Will Change The Focal Length Of Eye Lens.

Q3. What Vision Related Problems Occur When The Diet Of Vitamin A? 

Ans. We Know That Vitamin A Is Good For Eyesight. If Our Food Do Not Have Vitamin A. Then Person Will Not Able To See In Night Or In Low Light. It Is Called Night Blindness. At The Last, Due To Dryness Of Eyeball, The Softening And Clouding Of The Cornea And Other Problems. It Causes Blindness To The Person.

Chapter- Light And Vision

By Anmol

8th (D) {1}