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Priyanshu answered 1 year(s) , 10 month(s) ago

what is the derivation of mirror formula of concave and convex mirror?

Consider the shown figure where O is a point object and I is corresponding image.
CB is normal to the mirror at B.
By laws of reflection,

For small aperture...

Asked by Chayanika

Nov 16

  • 6 Answers
  • 29 Likes
  • 115744 Views
Anand answered 1 year(s) , 4 month(s) ago

What is the difference between a virtual image and a real image?

The following are the main differences between a real image and virtual image. 

1.A real image can be caught on a screen whereas a virtual image cannot be caught on a screen.
2. A real i...

Asked by Nidhi

Dec 3

  • 15 Answers
  • 23 Likes
  • 90797 Views
Priyanshu answered 1 year(s) , 6 month(s) ago

what is the uses of convex lens in daily life

Uses of convex lens are:
1) Convex lens is used in microscopes and magnifying glasses to subject all the light to a specific point.
2) Convex lens is used as a camera lens in cameras as they foc...

Asked by Unmukt

Jan 19

  • 6 Answers
  • 10 Likes
  • 76023 Views
Syeda answered 1 year(s) ago

The absolute refractive indices of glass and water are 4/3 & 3/2, respectively. If speed of light in glass is 2x108 m/s , calculate the speed of light in vacum and water.( 2015 Boards Que. )

Actually, n g = 3/2 and n w = 4/3.

Absolute Refractive Index of a medium = Speed of light in vacuum/Speed of light in the medium

Speed of light in glass =...

  • 3 Answers
  • 4 Likes
  • 51007 Views
Syeda answered 1 year(s) , 11 month(s) ago

If the speed of light in vacuum is 3x10⁸ m/s, find the speed of light in a medium of absolute refractive index 1.5.

Refractive index of a medium = Speed of light in vacuum/Speed of light in a medium

1.5 = 3 x 10 8 / Speed of light in medium

Speed of light in the medium = 3 x 10...

Asked by V.m.hameed

Jan 28

  • 2 Answers
  • 3 Likes
  • 42655 Views
Janhavi answered 4 year(s) , 3 month(s) ago

If the image formed by a mirror for all positions of the object placed in front of it is always erect and diminished, what type of mirror is it ? Draw a ray diagram to justify your answer. Where and why do we generally use this type of mirror?

A convex mirror forms an erect diminished virtual image for all the positions of the object placed in front of it.

A convex mirror is used as rear view mirrors in automobiles...

  • 2 Answers
  • 3 Likes
  • 37352 Views
Syeda answered 1 year(s) ago

why does the ray passing through the centre of curvature of a concave mirror retraces it's path.

Answer: 



A ray of light passing through the centre of curvature of a concave mirror retraces its path (gets reflected along the same path), because as the ray of light passes throu

...

Asked by Venkatesh

Nov 21

  • 2 Answers
  • 0 Like
  • 32727 Views
Agam answered 1 year(s) , 2 month(s) ago

An object 5 cm in size is placed at a distance of 20 cm from the concave mirror of focal length 15 cm. At what distance from the mirror should..

Object-size, h = + 5.0 cm;
Object-distance, u = – 20.0 cm;
Focal length, f = –15.0 cm;
Image-distance, v = ?
Image-size, h′ = ?
Mirror formula is             (1/v) + (1/u...

Asked by David

Dec 5

  • 2 Answers
  • 2 Likes
  • 32071 Views
Agam answered 1 year(s) , 9 month(s) ago

twinkling of stars

The phenomenon that causes stars to twinkle is atmospheric refraction. That is, the air above us is a big ocean of not very dense fluid that has a small bending effect on light that passes through it. If it wer...

Asked by Santosh

Feb 24

  • 3 Answers
  • 4 Likes
  • 29845 Views
Janhavi answered 4 year(s) , 6 month(s) ago

What for concave and convex mirrors and lenses are used?

Uses of Concave Mirrors

  • Concave mirrors are used as shaving mirrors to see a larger image of the face.
  • Dentists use concave mirrors to view the back of the tooth. ENT doc
...

Asked by Sai Bhargav

Dec 4

  • 1 Answer
  • 2 Likes
  • 29245 Views
Agam answered 1 year(s) , 10 month(s) ago

A convex lens of focal length 20 cm produces 3 times magnified real image of an object. Find the position of the object

there could be two position of object 

i) For real image
Given , M = -3        

 m = v/u

-3 = v/u

v = -3u    ...................... (i)
by lens formula
 1/f

...

Asked by Lavanya

Feb 7

  • 4 Answers
  • 1 Like
  • 25679 Views
Syeda answered 1 year(s) , 11 month(s) ago

A student wants to project the image of a candle flame on a screen 60cm in front of a mirror by keeping the flame at a distance of 15cm from its pole. -a- State the type of the mirror. -b- Find the linear magnification

a) Concave mirror
b) Linear Magnification m = -v/u 
u = -15 cm
v = -60 cm
m = -v/u = -60/15 = -4
c) 15 cm
d) Ray diagram - object between F and C.

Asked by Ayesha

Feb 27

  • 2 Answers
  • 0 Like
  • 25104 Views
Janhavi answered 4 year(s) , 8 month(s) ago

Refractive index of water w.r.t. glass

Refractive index of medium 2 w.r.t. medium 1 is written as 
n 21  = speed of light in medium 1/ speed of light in medium 2
n 21  = v1/v2
Refractive index of glass...

Asked by Gaurav

Oct 6

  • 1 Answer
  • 0 Like
  • 22287 Views
Syeda answered 1 year(s) , 11 month(s) ago

What is the focal length of a plane mirror?

Focal length of a plane mirror is infinity.

(A plane mirror can be considered as a spherical mirror of infinite radius of curvature. Focal length is half of radius of curvature and hence it is i...

Asked by R murali

Oct 19

  • 2 Answers
  • 3 Likes
  • 20961 Views
Janhavi answered 4 year(s) , 5 month(s) ago

A convex mirror used for rear view on an auto mobile has a radius of curvature of 3.00 m. If a bus is located at 5 m from the mirror, then the position of the image is at _______.

Radius of curvature of the convex mirror R = 3 m
Focal length of the convex mirror f = R/2 = 1.5 m  (positive for convex mirror)

Object (bus) distance u = − 5 m
Image distance v...

Asked by Vaishnavi

Dec 29

  • 1 Answer
  • 5 Likes
  • 19556 Views
Janhavi answered 4 year(s) , 3 month(s) ago

A 4 cm tall object is placed perpendicular to the principal axis of a convex lens of focal lengh 20 cm . the distance of the object from the lens is 15 cm . Find the nature, position and the size of the image .

Height of object ho = 4 cm
Focal lenght of convex lens = 20 cm
Object distance u = -15 cm
Image distance v = ?
Image height hi = ?

Lens formula: 1/v  -  1/u  =  1...

Asked by Jayasree

Mar 4

  • 1 Answer
  • 1 Like
  • 18520 Views
Syeda answered 1 year(s) , 11 month(s) ago

At what distance from a concave mirror of focal length 10 cm should an object 2 cm long be placed in order to get an erect image 6 cm tall?

Answer.

    Focal length of concave mirror f = -10 cm
Height of the object h o = 2 cm
Height of the image h i = 6 cm
Magnification m = h i/h...

Asked by Neha

Feb 12

  • 2 Answers
  • 2 Likes
  • 17973 Views
Agam answered 1 year(s) , 1 month(s) ago

A spherical mirror produces an image of magnification - 1 on a screen placed at a distance of 50 cm from the mirror. State

(a) Concave Mirror
(b) The distance of image from the object is zero, i.e. a real inverted image of the same size is formed at the same place where object is placed. (Actually the object is placed at th...

Asked by Sabu

Jan 25

  • 4 Answers
  • 0 Like
  • 17080 Views
Syeda answered 1 year(s) ago

A student wants to project the image of candle flame on the wall of school laboratory using lens. (a)Which type of lens should he use and w..

(a) The student should use a convex lens as it can form a real image (on a screen).
(b) (i) To get a magnified image on the wall, the candle flame should be placed between F and 2F from the lens. (ii) T...

Asked by Sabu

Jan 25

  • 2 Answers
  • 1 Like
  • 16628 Views
Syeda answered 1 year(s) , 11 month(s) ago

What is the difference between absolute and relative refractive indices?

Answer.

The absolute refractive index (μ) of a medium is the ratio of the speed of light in vacuum (c) to the speed of light in that medium (v), i.e. μ = c/v.

The refractive index of me

...

Asked by Om prakesh

Nov 13

  • 2 Answers
  • 2 Likes
  • 15721 Views
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