Telangana SCERT Class 10 Physical Science Chapter 1 Solution – Reflection of light at curved surfaces. Here in this post we provides Class 10 Physical Science Reflection of light at curved surfaces Telangana State Board Solution. Telangana State Board English Class X Medium Students can download this Solution to Solve out Improve Your Learning Questions and Answers.
Telangana State Board Class 10 Physical Science Chapter 1 Reflection of light at curved surfaces Solution:
Chapter: – 1
Reflection of light at curved surfaces
Exercise: – Reflections on concepts
1) Where will the image be formed when we place an object on the principal axis of a concave mirror at a point between focus and centre of curvature? (AS1)
Ans: – When we place an object on the principal axis of a concave mirror at a point between focus and centre of curvature the image will from beyond the centre of curvature.
2) State the differences between convex and concave mirrors? (AS1)
Ans: –
Concave mirror |
Convex mirror |
Inner side of spherical mirror is reflected. | Outer side of spherical mirror is reflected. |
Converging in nature | Diverging in nature. |
Real image is formed. | Virtual image is formed. |
3) Distinguish between real and virtual images.
Ans: – The difference between real and virtual image is that the real image is formed on screen with the help of concave mirror and the virtual image is formed by the help f convex mirror.
4) How do you get a virtual image using a concave mirror?
Ans: – The virtual image is formed when an object is placed between the focus and the Pole of that convex mirror.
5) What do you know about the terms given below related to spherical mirrors? (AS1)
a) Pole b) Centre of curvature c) Focus d) Radius of curvature e) Focal length f) Principal axis g) Object distance h) Image distance i) Magnification.
Ans: –
Application of concepts
1) Find the distance of the image when an object is placed on the principal axis at a distance of 10 cm in front of a concave mirror whose radius of curvature is 8 cm.
Ans: – As we know that focal length F = centre of curvature/2.
So, F=8/2 = 4cm.
The mirror formula is, 1/f= 1/v + 1/u.
Here, f=-4(as concave mirror); u=-10cm.
So, 1/v= 1/u – 1/f;
Or, 1/v = -1/10 + 1/4 = -20/3.
Then the distance of the image is 6.66 cm.
2) The magnification product by a mirror is +1. What does it mean?
Ans: – The magnification is +1 which implies that the image is virtual and erect which formed by the plane mirror.
3) If the spherical mirrors were not known to human beings, guess the consequences.
Ans: – The spherical mirror has great impact in the human being as this spherical mirror helps us in various way. The concave and convex mirror has various uses in different places as well as this mirror also used in medical purpose. Our glasses also made by this mirror.
4) Draw suitable rays by which we can guess the position of image formed by a concave mirror?
Ans: –
5) Show the formation of image with a ray diagram when an object is placed on the principal axis of a concave mirror away from the centre of curvature?
Ans: –
6) Why do prefer a convex mirror as a rear-view mirror in the vehicles?
Ans: – The convex mirror always gave the virtual, erect image so it gives the wide view from back side so for this benefit we use the convex mirror as a rare view.
Higher Order Thinking Questions
1) A convex mirror with a radius of curvature of 3 m is used as rear-view mirror for a vehicle. If a bus is located at 5 m from this mirror, find the position, nature and size of the image?
Ans: – As we know the mirror formula is,
1/f= 1/v + 1/u;
Here objects distance(u)=-5cm; and focal length=Centre of curvature/2 = -3/2.
So, 1/v= 1/u – 1/f;
Or, 1/v = 1/-5 + 2/3;
Or, v= -15/13=-1.15.
So, the image will be virtual and erect and it will be at a distance of 1.15cm.
2) To form the image on the object itself, how should we place the object in front of a concave mirror? Explain with a ray diagram ?
Ans: – To form the image on the object itself we should place the object in front of a concave mirror as that the ray is parallel to the principal axis and other should be passes through the focus.
Multiple choices questions
1.) If an object is placed at C on the principal axis in front of a concave mirror, the position of theimage is
a) at infinity b) between F and C c) at C d) beyond C.
Ans: – Option (c) at C.
2.) We get a diminished image with a concave mirror when the object is placed
a) at F b) between the pole and F c) at C d) beyond C.
Ans: – option (d) beyond C.
3.) We get a virtual image in a concave mirror when the object is placed
a) at F b) between the pole and F c) at C d) beyond C.
Ans: – option (b) between the pole and F.
4.) Which of the following represents Magnification ‘m’- option(b) (ii) and (iii).
5.) Ray which seems to be travelling through the focus of a convex mirror, path of the reflected ray of an incident
a) parallel to the axis b) along the same path in opposite direction c) through F.
Ans: – option (a) parallel to the axis.
6.) Size of image formed by a convex mirror is always
a) enlarged b) diminished c) equal to the size of object d) depends on position of object.
Ans: – option (b) diminished.
7.) An object is placed at a certain distance on the principal axis of a concave mirror. The image is formed at a distance of 30 cm from the mirror. Find the object distance if radius of curvature R =15 cm
a) 15 cm b) 10 cm c) 30 cm d) 7.5 cm.
Ans: – option (a) 15cm.
8.) All the distances related to spherical mirrors will be measured from
a) object to image b) focus of the mirror c) pole of the mirror d) image to object.
Ans: – option (c) pole of the mirror.
9.) The minimum distance from real object to a real image in a concave mirror is
a) 2f b) f c) 0 d)2f.
Ans: – option (c) 0.
Additional Question and Answer:
Question 1. What kind of mirror is used in cars, and for what purpose?
Answer : In automobiles, Convex mirrors are used , because convex mirrors produce small(diminished image), virtual images and convex mirrors give a wide range of view.
Question 2. What kind of lens is used in front lights on cars?
Answer : In automobiles, we use convex lenses where the bulb is kept at the focal point of the convex lens so that the lens can produce its image at infinite means light can travel up to long distance.
Question 3. Which type of mirror can produce a laterally inverted image ?
a) Plane mirror
b) Convex mirror
c) Concave mirror
d) All of the above
Answer :
D
Plane and convex mirrors always produce laterally inverted images.
But in the case of a concave mirror when a virtual image is formed it will be also laterally inverted. That means all the above mirrors can produce laterally images.
Question 4. In Reflection angle of incidence is equal to the angle of incidence for ?
a) Plane surface
b) Curved surface
c) Irregular surface
d) All of the above
Answer :
D
angle of incidence will be always equal to the angle of reflection for reflection from all surfaces.
Question 5. When an object is placed in front of a mirror at 10 cm away from the mirror of 5 cm height then size and distance of image from object will be respectively ?
a) 5m and 10 m
b) 5m and 20 m
c) 10m and 10m
d) 10m and 20m
Answer :
B
Image formed by plane mirror will always be same distance from mirror as object is from mirror and size will be same as object
So, here from object to image size will be double ( 20m) and height will be the same as object 5m.
Question 6. Find the angle of reflection from the second second mirror when light fall on first mirror at
a) 25o
b) 30o
c) 65o
d) 35o
Answer :
When light falls on surface one it reflect at same angle 25o and it will make same incident angle at second surface so after reflection through second it will make same 25o, as angle of incidence will always be equal to the angle of reflection for reflection from all surfaces.
Question 7. When to parallel light incident on a concave mirror which is not parallel to the principal axis they will meet at ?
a) Focus
b) Focal plane
c) Center of curvature
d) Infinite
Answer.
B
When parallel light incident on a concave mirror which is not parallel to the principal axis they will meet at Focal plane , which passes through the focal point and perpendicular to the principal axis.
Question 8. What is the relation between focal length and center of curvature for a spherical mirror ?
a) f = R/2
b) R= f/2
c) f = R
d) None of the above
Answer.
A
Relation between focal length and center of curvature for a spherical mirror is given by R=2f
Question 9. What will be the position of the image in case of a point object for a concave mirror ?
a) When object is at infinite
b) When object is at focal
c) When object is at center of curvature
d) When object is at between focal point and center of curvature
e) When object is a at between infinite and center of curvature
Answer.
When object is at infinite image will form at focal point
When an object is at focal, the image will form at infinity.
When the object is at the center of curvature, the image will form at the center of curvature.
When an object is between focal point and center of curvature, the image will form between infinite and center of curvature.
When an object is between infinite and center of curvature, the image will form between focal point and center of curvature.
Question 10. Draw a ray diagram for image formation from convex mirror
Answer:
Images formed by convex mirrors will always be erect ,diminished and virtual.
Question 11. Which of the following represent the correct relation between f,u,and v for a spherical mirror. Where u is object distance from center of curvature , f is focal length and v is image distance from center of curvature.
a) 1/f = 1/u + 1/v
b) 1/f = 1/u – 1/v
c) 2/f = 1/u + 1/v
d) None of the above
Answer:
A
We know the relation between f,u,and v for a spherical mirror is given by
1/f = 1/u + 1/v where, u is object distance from center of curvature , f is focal length and v is image distance from center of curvature.
Question 12. If an object size of 6 cm, is placed at 5 cm in front of a concave mirror and focal length 25 cm. Find the nature and the size of the image.
Answer:
Here
u = +5 cm
f = = -25 cm
ho = 6 cm
By mirror formula
1/f = 1/u + 1/v
1/(-25) = 1/5 + 1/v ⇒ 1/v = 1/(-25) – 1/5
1/v = (-1-5)/25 ⇒ v = – (-25)/6 cm
And size of the object:
We know m = h_i/h_o = |-v/u|
h_i/h_o = 25/6 ⇒ h_i = 25 cm
Nature of the image : virtual , enlarge and erect
Question 12. In mirror formula all distances should be measured from ?
a) Focal point
b) Center of curvature
c) Pole
d) Infinite
Answer:
C
While using the mirror formula all distances should be measured from the pole.
Pole is nothing but the center of curvature.
Question 13. When should we place a mirror to produce an image on the center of curvature?
a) Focal point
b) Infinite
c) Center of curvature
d) Pole
Answer:
C
When an object is placed at the center of curvature image also will form at the center of curvature.
Question 14. Define the following ?
Center of curvature
Pole
Focal point
Principal axis
Answer:
Center of curvature: center of curvature is the center of the sphere of which the spherical mirror is a part. It is denoted by ‘C’
Pole: center of,center of curvature is called pole it is denoted by ‘P’.
Focal point: focal point is a point in the principal axis where all rays which are parallel to the principal axis will meet at a point and that point is called the focal point.
Principal axis: axis which passes through the pole and center of curvature is called a principal axis.
Question 15. Why did we polish one side of the mirror in case of image formation from a spherical mirror?
Answer :
One side of mirror polish because if not polish one side refraction will take place and very small intensity of light reflected from curvature and hence image formed by reflection will be blurred.
Question 16. Give any two examples of reflection in daily life which happen naturally?
Answer:
Diamond sparkle.
Rode looks wet on summer days.
Flash photography.
Question 17. Which type of mirror is used by the dentist to check dental problems.
a) Convex mirror
b) Concave mirror
c) Plane mirror
d) Anyone can be used
Answer :
B
Concave mirror, when an object is placed at a distance which is less than focal length then the object will enlarge in size , because of this property the dentist used a concave mirror.
Question 18. Virtual image formed by a spherical mirror always be?
a) Real
b) Erect
c) Enlarge
d) Diminished
1) A and C
2) B and D
3) B and C
4) Only B
Answer:
3
Virtual images always form erect and enlarge images so the answer will be 3.
Question 19. Real image formed by a spherical mirror always be?
a) Always enlarge
b) Always diminished
c) Can be enlarge and diminished depending on position of object
d) Real images always form inverted images.
1) Both A and C
2) Both A and D
3) Both B and C
4) Both C and D
Answer:
4.
Real image formed by a spherical mirror will always be an inverter and size of the object depends on where the object is placed. It can be diminished and enlarged also.
Question 20. If the focal length of a mirror is given by 20 cm then what will be the radius of curvature of the mirror?
Answer:
40 cm
We know the relation between focal length and radius of curvature for spherical mirror is given by f=R/2
So R=2 f
So R= 40 cm
Add suggested experiments