Question

Name the instrument used to measure power of lens

Answer 1

Answer :- focimeter

Explanation : focimeter is used to determine power of lens . it is known as lensometer and vertometer . It can determine axis , position of the optical centre of a given lens , power of cylindrical lens , also it can determine spherical power . Eyes specialist use it for finding defect in eye vision of patients .
Here , in figure , shown a type of focimeter

Answer 2

The unit used to measure the power of lens is "Diopter"