Telangana SCERT Class 7 Science Chapter 9 Solution – Reflection Of Light. Here in this post we provides Class 7 Science Reflection Of Light Telangana State Board Solution. Telangana State Board English Class VII Medium Students can download this Solution to Solve out Improve Your Learning Questions and Answers.
Telanagana State Board Class 7 Science Chapter 9 Reflection Of Light Solution:
Q.1. Vidya made a Periscope making slits like this as shown in the figure. Will it work or not? Explain your answer. Try to make a periscope like this and see whether it works or not?
Ans.
No, it will not work.
This periscope is not perfect, Because in this case mirror strips did not lied parallel in each other. So if the windows should open directly there were no reflecting surfaces of the mirror strips.
If they are not parallel, you don’t be able to see thing from window 2 lying in from of window 1. That mean this periscope did not work properly. We can’t view objects from room which stays in outside.
(2.) (i) Draw reflected ray in the figure given here.
(ii) Mark the position of the image in the figure given here by dotted lines.
(3.) How do you relate angle of reflection and angle of incidence?
Ans. Angle of incidence is equal to an angle of reflection. We donate angle of incidence with <i and the angle of reflection with <r. Means measure of incidence is equal to measure of reflection.
Measure of <i = Measure of <r
What will be the angle of reflection when angle of incidence is
i) 60° ii) 0°
Ans. When angle of incidence is 60 degree then the angle of reflection is also 60 degree Because, measure of <i = Measure of <r.
When angle of incidence is 0 degree then the angle of reflection is also 0 degree.
(4) Imagine that your sister is viewing a cricket match on a TV and you are viewing the same cricket match in a mirror which is opposite to the TV. What difference do you notice in the match?
Ans. When you notice the match in mirror there is lateral inversion occur. For this in a mirror, right of an object appears left and left of the object appears right.
Suppose the batsman is right handed, when you watch the same batsman in mirror, he will appear left handed. If the bowler is bowling from right side of the stump, in the mirror he could appear to be bowling from left side of the stump.
Do experiments and check whether your guesses are correct or not? Give reasons
Ans. Fig – 1 – Here I observe two image.
Fig – 2 – In tghat case two images are observe and one copy image also seen. means total three image.
This experiments in first case I observe two image but that is actually the copy image in front the mirror and also only one image observe so here my guese is wrong.
In second case keep the mirrors in such a way that the angle between the mirrors is 90 degree and observe the images. Here mirrors images are observe. Irrespective of size of the plane mirror, the size of the image in the mirror is equal to the size of the objects. So in 2nd experiments images three images created. Because the distance from the object to a plane mirror is equal to the distance of the image from the mirror and also the size of the real objects and mirror image is same.
(9) Write examples of multiple images formed in your daily life?
Ans. Multiple images that are generally formed in our daily life are on television, on camera, on glasses, on mirrors, on shiny surfaces in trial room in a shop etc.
(11.) Sai lighted a candle in his house when power went off. His mother placed it in front of a mirror. Sai observed something that excited him. What change would have excited Sai? Some questions came to his mind. Can you guess the questions? Write a few such questions.
Ans. Some questions are –
i) Sai must be thinking what us fire?
ii) How fire is formed?
iii) Why is it so bright after lightning the candle?
iv) Why did she kept the mirror?
v) Why the candle light is increased?
vi) Why was the candle not visible in the mirror when there was no light.
(12.) Unexpectedly some water sprinkled on a mirror while Madhu was shaving his face. Did he observe any difference in his image? If yes, explain why?
Ans. Yes, he will observe some difference the reason behind it is –
The mirror is a perfect reflector of light but water is not and therefore the reflection of the man gets changed when water falls on the mirror.
When water fell on the mirror and as a result, his reflection got a little changed.
Because a mirror image (a plane mirror) is a reflected duplication of an object that appears almost sane or identical.
so the surface where the water has been sprinkled will act as a convex lense.
(15) What is the angle between two plane mirrors when there are five images?
Ans: – Number of images = 5
Total angle is = 360o
The angle between two plane mirror is = 360/5
= 72o
(16) What is the difference between convex and concave mirror? Draw the diagram of concave and convex mirrors.
Ans: – In convex lens, the curve is outward facing, but in concave lens the curve faces inward.
That means when the reflecting surface of a mirror is convex, then it is called convex mirror.
But the reflecting surface of a mirror is concave, it is called concave mirror.
Convex mirrors are diverging nature.
But concave mirror are converging nature.
Convex mirror mean inner side of a mirror is reflecting.
Concave mirror mean outer side of a mirror is reflecting.
(17) Where do you find irregular reflection in daily life? Give some examples.
Ans: – Any places where the surfaces are not plane mean curve.
Examples: We see everything is surroundings with the help of our eyes due to continuous irregular reflection.
Reflections of light from clothing’s, stones, metal objects, rocks, etc are some of irregular reflection.
(18) Mirrors help us to see all the objects around us without turning our heads. Write about the role of mirrors in our life.
Ans: – Mirrors are essential to every home. IT helps us in our daily life. Mirror reflects to us how we took, how clothes fit us, and how things fit. Every were we go, there are almost mirrors are always present. All clear mirrors that reflect the image of the things perfectly, or the person in front of them.
Mirrors like convex and concave mirrors are also used for, making lenses of sunglasses, in telescope, magnifying glass, headlights, head mirrors, as shaving purpose mirror, etc. These all are essential in our daily life.
So we can say that mirror plays an important role in our daily life.
(19) Army people can see their enemies while hiding themselves with the help of periscope. Write about the use of periscope for their security.
Ans: – With the help of periscope army people locate the enemy and at the same time doesn’t let the enemy see them.
The periscope is used to determine the distance of the torpedo attack, it helps the correct time to fire the torpedo with high speed.
The periscopes are used to observe the dangerous places, they are used in the fuel tasks to see around and above the vehicles.
(20) Imagine what would happen if there are no near view mirrors attached to vehicles and there are no concave mirrors in head lights of the vehicles. Write about the role of convex and concave mirrors in safe driving.
Ans: – Convex and concave mirrors are plays an important role in safe driving. These are rear view mirrors. These are used by drivers to see vehicles which are moving behind or beside of the vehicles without turning their heads.
It captures the image at a mirror from a far distance.
It also captures an image of road in smaller image.
(21) Collect information from your elders and shopkeepers about where we use more mirrors and why?
Ans: – A mirror gives a room a bright and open beautiful feeling.
So we use more mirrors in small rooms, corridors, halls especially.
Be sure the mirror placed in night place and it reflects something nice. You place the mirror on the walls of the room, to make the room looks like larger.
(23) Collect information about which objects of your school and home work like a mirror and why? Identify the similarities among those objects
Ans: – Tiles in our school, wrist watch, water, spoon in our home, desk at our school, spectacles, utensils in our home which are shiny screen of phones, disc(CD), published glass etc.
These all are work like a mirror because of their shiny surfaces
They are work like reflection of light.
(24) Can we see rear view mirror in place of phone mirror Yes/No, give the reasons.
No, we cannot use rear view mirror.
Rear view mirror is convex mirror. Rear view mirror has a carve surface, so it spreads light over a long distance.
But in the ease plane mirror reflects light and gives the image with same size as the objects is obtained.
So the rear view mirror cannot be used in the place of plane mirror.
(25) A mirror is hanging in your room. Your friend is sitting in the same room in a chair. If your friend wants to see you in a mirror, how will you adjust your position? Explain.
Ans: – Look at in the mirror what you can see and find out where your partner is looking in the picture. Then you can turn to be able to see to your friend.
In another way where the mirror is placed walk near to it and see the room’s style, then you moved from right of left, in that way your friend see you in that mirror.
Thank you