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What are sign conventions of mirrors and lens

 

Sign Conventions for spherical Mirrors as well as lens are  well explained in your study material. Please go through it and do get back to us in case of any doubts. Follow the links  to get it .
https://www.meritnation.com/cbse/class10/studymaterial/science/science/matter-in-our-surroundings/10_154_8643#slide1_sign-convention-in-the-mirror-formula-and-magnification 
https://www.meritnation.com/cbse/class10/studymaterial/science/science/light-reflection-and-refraction/10_154_8653#slide8_lens-formula-magnification-and-power

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 Spherical Mirrors Lenses 

f) Focal Length (
+ for a converging lens  + for concave mirrors 
- for a diverging lens  - for convex mirrors 
)  o d Object Distance (
bject)  + if the object is to the left of the lens (real o + if object is in front of the mirror (real object)
- if object is behind the mirror (virtual object)
*
al object) - if the object is to the right of the lens (virtu
*
)  i d Image Distance (
 lens by a real object  e) + for an image (real) formed to the right of the + if the image is in front of the mirror (real imag
 lens by a real object  - for an image (virtual) formed to the left of the - if the image is behind the mirror (virtual image)
)  m Magnification (
to the object  object + for an image that is upright with respect  + for an image that is upright with respect to the 
 to the object.  object -for an image that is inverted with respect - for an image that is inverted with respect to the
*
his happens, the object distance
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Sign Conventions for spherical Mirrors:

I. Objects are always placed to the left of the mirror i.e. light must fall on the mirror from left to right.

II. All distances are measured from the pole of the mirror.

III. Distances along the direction of the incident ray (along positive x- axis) are taken as positive, while distances along the direction of the reflected ray (along negative x-axis) are taken as negative.

IV. Heights measured perpendicular to and above the principal axis (along positive y-axis) are taken as positive.

V. Heights measured perpendicular to and below the principal axis (along negative y-axis) are taken as negative.

These sign conventions can also represented in the following diagram:

 

Sigh Convention for Lenses

I. Object is always placed to the left of the lens i.e., the light must fall on the lens from left to right.

II. All distances parallel to the principal axis are measured from the optical centre of the lens.

III. Distances along the direction of incident rays (along positive x-axis) are taken as positive, while distances opposite to the direction of incident rays (along negative x-axis) are taken as negative.

IV. Distances measured above the principal axis (along positive y-axis) are taken as positive.

V. Distances measured below the principal axis (along negative y-axis) are taken as negative.

These sign conventions are represented in the following diagram:

 

Best Wishes @!

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 superb n well explained answer afzalhusain........well done........

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excellent afzal. Nice anwer. my   to U

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 Awesome guys.

@ Afzal, ur answer is too good and is same as meritnation's .

 I am giving u a thumb up. 

@ Sayali Taralkar, u 2 a good answer.

Thumbup 2 u 2oooo

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Yehhhhhh Afzal, u have just done Ctrl+C and Ctrl+p process man,

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nice work u have me a lot................

thanks

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please also write about them separately it seems to be very confusing

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 As answered by Star_shine.

Nice very nice

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 Sayali......thumbs up!

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for concave mirror, f = always -ve, u = always -ve, v = maybe -ve or +ve depending on situation, m =  maybe -ve or +ve depending on situation

for convex mirror, f = always +ve, u = always -ve, v = always +ve, m = always +ve

for concave lens, f = always -ve, u = always -ve, v=  always -ve, m = maybe -ve or +ve depending on situation

Hope this helps!!!-

Vivek Saahil

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