Spot the wrong sign convention (CBSE Cl 10 Light)

Exercise and reference answers

Questions

1. Statement parts

   1. For
   2. convex
   3. mirror
   4. :
   5. focal
   6. length
   7. is
   8. negative

   Correction

   A convex mirror has a virtual focus behind it; focal length is positive by sign convention.

   Incorrect part

   negative

2. Statement parts

   1. For
   2. concave
   3. lens
   4. :
   5. focal
   6. length
   7. is
   8. positive

   Correction

   A concave lens diverges light; its focal length is negative.

   Incorrect part

   positive