Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
NEET2026PhysicsChapterActual

An optical system is constructed by placing three thin lenses coaxially in contact. The focal lengths of the three lenses are f , f 2 , and -f , respectively. If the lateral magnifications produced by these individual lenses are m₁ , m₂ , and m₃ , what is the equivalent power and the total lateral magnification of the system?

Options

  1. A2 f and m₁ + m₂ + m₃
  2. B4 f and m₁ m₂ m₃
  3. C2 f and m₁ m₂ m₃
  4. D4 f and m₁ + m₂ + m₃

Correct answer

C. 2 f and m₁ m₂ m₃

Step-by-step solution

The equivalent power of a combination of thin lenses in contact is the sum of their individual powers. P = P₁ + P₂ + P₃ P = 1 f₁ + 1 f₂ + 1 f₃ Substituting the given focal lengths f₁ = f , f₂ = f 2 , and f₃ = -f : P = 1 f + 2 f - 1 f = 2 f For a system of lenses in contact, the total lateral magnification is the product of the lateral magnifications produced by the individual lenses. M = m₁ m₂ m₃ = m₁ m₂ m₃ Answer: 2 f and m₁ m₂ m₃

Practice Chapter on Quantrex Academy →

More from Chapter

A solid spherical body of radius R , density , and specific heat capacity s is initially at temperature T₀ . It is placed in a vacuum chamber at absolute zero and cools by emitting 2026A straight canal has motorboats departing from two terminals at opposite ends. The motorboats depart at regular intervals of T minutes in both directions and travel at a constant s 2026A wooden crate is released from rest at the top of a ramp inclined at 37^ to the horizontal. When the ramp is perfectly smooth, the crate reaches the bottom with a speed v . When t 2026A uniform horizontal beam of mass 6 kg and length L is hinged to a vertical wall at one end. The other end is supported by a light inextensible wire attached to the same wall, maki 2026A bullet P of mass 30 g moving with a speed of 200 m/s penetrates a target and comes to rest after travelling a distance of 10 cm inside it. Another bullet Q of mass 20 g moving wi 2026A small block of mass m is placed at the highest point of a smooth fixed sphere of radius R . It is given a horizontal initial speed v₁ such that it slides down the surface. The bl 2026A block of mass 2 kg is projected with an initial speed of 14 m/s on a rough horizontal surface. The coefficient of kinetic friction between the block and the surface is 0.2 . Afte 2026A uniform horizontal circular disc of mass M and radius R is rotating freely about a vertical axis passing through its center at an angular speed of 40 rpm . Two small blocks, each 2026 Full Chapter list All NEET PYQs