Home › UP Board Class 10 › physics › c10lensformula › Per NCERT, when several LENSES are placed in CON…
Per NCERT, when several LENSES are placed in CONTACT, what is the NET POWER?
AProduct of individual powers
BCannot be computed
CAverage of individual powers
DThe ALGEBRAIC SUM of individual powers: P = P₁ + P₂ + P₃ + ...
Answer & Solution
Correct answer: D. The ALGEBRAIC SUM of individual powers: P = P₁ + P₂ + P₃ + ...
Per NCERT §9.3.8, contact-lens net power = algebraic sum. Used by opticians in eye testing.
Related questions
Per NCERT, a combination of two lenses of power +2.0 D and +0.25 D in contact is equivalenPer NCERT, if a lens has POWER = −2.5 D, what is its FOCAL LENGTH — and is it convex or coPer NCERT, if a lens has POWER = +2.0 D, what is its FOCAL LENGTH — and is it convex or coPer NCERT, what is 1 DIOPTRE — the SI unit of lens power?Per NCERT, what is the POWER (P) of a LENS — and what is its SI unit?Per NCERT Example 9.4, for the same convex lens problem (f=+10, u=−15), what is the MAGNIFPer NCERT Example 9.4, a convex lens (f = +10 cm) has an object at u = −15 cm. What is thePer NCERT Example 9.3, a concave lens (f = −15 cm) forms an image at v = −10 cm. What is t