Question

Q4.Very short answer type question (Give one word for the following)
1. Name the device which uses the principle of multiple reflection.
2. One example of natural dispersion
3. What is the function of a periscope in a submarine?
Q5.Short answer type questions
1. What is the difference between the surfaces of a sheet of sandpaper and a mirror?
2. Calculate the number of images formed by plane mirror kept an angle of (i) 30° (ii)
60° to each other?
3. ‘The law of reflection only holds true for regular reflection’. Is this statement true or
false? Explain you answer
4. A Wall reflects light and a mirror also reflects light. What difference is there in the
way they reflect light?
First person to solve this will awarded by 40 points! And become the brainliest answer plz answer accurate this is important

Answer 1

Answer:

1. Periscope

2. The example of dispersion is throughing a little piece of paper all over a floor

3. A periscope's basic purpose is to allow submarine crews to see objects above the water while the ship remains submerged.

1. => reflection of light from a plane mirror 1) it is a regular reflection2)light rays falls on a smooth and polished surface,a parallel beam of light is incident on a plane mirror,the reflected beam is also parallel.. .=>reflection of light from a sheet of paper 1) its a irregular reflection 2) light rays strike at different parts of a rough surface,each rays gets reflected from different points of rought surface in different direction.

2. There will be 5 images formed.

You have use the formula (360/angle) - 1, if 360/angle is even, otherwise you'll have to use 360/angle..

Here, the given angle is 60°. So 360/angle is 6. Hence, the number of images formed will be 6–1=5 as 6 is an even number

similarly,

There will be 11 images formed when two mirrors are placed at an angle of 30°.

3. Laws of reflection holds true. This statement is absolutely right . It's because due to irregularities on surface, reflected rays scatter in different directions

4. A wall has a rough surface, so the reflection by a wall is a diffuse reflection. A parallel beam of light incident on it is reflected in different directions. A mirror surface is smooth, so the reflection by a mirror is a regular reflection. A parallel beam of light incident on it, gets scattered by making reflected rays in different direction.

Hope it hepls you.....

Mark as brainlist

Answer 2

Explanation:

1. Two devices which works on the principle of reflection of sound:
2. i) Stethoscope
3. ii) SONAR system (Sound Navigation And Ranging)
4. The example of dispersion is throughing a little piece of paper all over a floor . Water droplet acts as a prism. When a light or sunlight passes through the rain drop or water droplet then it undergoes refraction then dispersion.
5. A periscope's basic purpose is to allow submarine crews to see objects above the water while the ship remains submerged. A simple periscope can be constructed out of a vertical tube with mirrors placed at a 45-degree angle at the top and bottom of the tube.
6. => Reflection of light from a plane mirror 1) it is a regular reflection2)light rays falls on a smooth and polished surface,a parallel beam of light is incident on a plane mirror,the reflected beam is also parallel. => Reflection of light from a sheet of paper 1) its a irregular reflection 2) light rays strike at different parts of a rough surface,each rays gets reflected from different points of rought surface in different direction.
7. Image formed by a mirror kept at an ange of 10 degree=360/angle-1
9. =360/10-1
10. =36-1
11. =35
12. Laws of reflection holds true. Due to irregularities on surface, reflected rays scatter in different directions. Mention against each of the following whether regular or diffused reflection will take place when a beam of light strikes. Regular reflection takes place.
13. A wall has a rough surface, so the reflection by a wall is a diffuse reflection. A parallel beam of light incident on it is reflected in different directions. A mirror surface is smooth, so the reflection by a mirror is a regular reflection.