A convex lens of focal length 25 cm is placed coaxially in contact with a concave lens of focal length 20 cm. Determine the power of the combination. Will the system be converging or diverging in nature?

Solution

Given, a convex lens placed coaxially in contact with a concave lens.
Power of convex lens, P₁ = $fraction numerator 1 over denominator plus space straight f subscript 1 end fraction space equals space fraction numerator 100 over denominator f subscript 1 left parenthesis space i n space c m right parenthesis end fraction space equals space fraction numerator 100 over denominator plus 25 end fraction space equals space 4 D$
Power of concave lens, P₂ = $fraction numerator 1 over denominator plus space straight f subscript 2 end fraction space equals space fraction numerator 100 over denominator f subscript 2 left parenthesis space i n space c m right parenthesis end fraction space equals space fraction numerator 100 over denominator negative 20 end fraction space equals space minus 5 space D$

So, Power of combination, P = P₁ + P_{2
= $4 D space plus space left parenthesis negative 5 D right parenthesis$
$equals space minus 1 D$}Since, power has negative magnitude; system of lenses is diverging in nature.

Some More Questions From Electric Charges and Fields Chapter

a) An electrostatic field line is a continuous curve. That is, a field line cannot have sudden breaks. Why not?
b) Explain why two field lines never cross each other at any point?

Figure shows tracks of three charged particles in a uniform electrostatic field. Give the signs of the three charges. Which particle has the highest charge to mass ratio?

For Daily Free Study Material Join wiredfaculty

Electric Charges And Fields

A convex lens of focal length 25 cm is placed coaxially in contact with a concave lens of focal length 20 cm. Determine the power of the combination. Will the system be converging or diverging in nature?

Some More Questions From Electric Charges and Fields Chapter

a) An electrostatic field line is a continuous curve. That is, a field line cannot have sudden breaks. Why not?
b) Explain why two field lines never cross each other at any point?

Figure shows tracks of three charged particles in a uniform electrostatic field. Give the signs of the three charges. Which particle has the highest charge to mass ratio?

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

Phone Number

Email Address

Loaction

For Daily Free Study Material Join wiredfaculty

Electric Charges And Fields

A convex lens of focal length 25 cm is placed coaxially in contact with a concave lens of focal length 20 cm. Determine the power of the combination. Will the system be converging or diverging in nature?

Some More Questions From Electric Charges and Fields Chapter

a) An electrostatic field line is a continuous curve. That is, a field line cannot have sudden breaks. Why not?b) Explain why two field lines never cross each other at any point?

Figure shows tracks of three charged particles in a uniform electrostatic field. Give the signs of the three charges. Which particle has the highest charge to mass ratio?

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

a) An electrostatic field line is a continuous curve. That is, a field line cannot have sudden breaks. Why not?
b) Explain why two field lines never cross each other at any point?