Thank you for registering.

One of our academic counsellors will contact you within 1 working day.

Please check your email for login details.
MY CART (5)

Use Coupon: CART20 and get 20% off on all online Study Material

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price: Rs.

There are no items in this cart.
Continue Shopping

Sign conventions of concave and convex mirror and convex and conave lens and every thing about it

Sign conventions of concave and convex mirror and convex and conave lens and every thing about it 

Grade:12

1 Answers

Arun
25763 Points
2 years ago

Sign convention in the case of concave mirror:

  • Since, object is always placed in front of the mirror hence the sign of object is taken as negative.
  • Since, the centre of curvature and focus lie in front of the concave mirror, so signs of radius of curvature and focal length are taken as negative in the case of concave mirror.
  • When image is formed in front of the mirror, the distance of image is taken as – (negative) and when image is formed behind the mirror, the distance of image is taken as + (positive).
  • Height of image is taken as positive in the case of erect image and taken as negative in the case of inverted image.

 

Sign convention in the case of a convex mirror:

  • Since, object is always placed in front of the mirror hence the sign of object is taken as negative.
  • Since, the centre of curvature and focus lies behind the convex mirror, so sign of radius of curvature and focal length are taken as + (positive) in the case of convex mirror.
  • In the case of convex mirror, image always formed behind the mirror, thus the distance of image is taken as positive.
  • In the case of a convex mirror, always an erect image is formed, thus the height of image is taken as positive.

Following sign convention is used for measuring various distances during the formation of images by lenses:

  • All distances on the principal axis are measured from the optical center.
  • The distances measured in the direction of incident rays are positive and all the distances measured in the direction opposite to that of the incident rays are negative.
  • All distances measured above the principal axis are positive. Thus, height of an object and that of an erect image are positive and all distances measured below the principal axis are negative.

The following table gives the sign convention for lenses:

Type of lens u v f Height of the image (hI Height of the object (hO)
    Real Virtual Real Virtual Real Virtual  
Convex - + - + No virtual focus - + +
Concave - No real image is formed - No real focus - No real image is formed
 

Think You Can Provide A Better Answer ?

Provide a better Answer & Earn Cool Goodies See our forum point policy

ASK QUESTION

Get your questions answered by the expert for free