Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Geometrical Optics question

2002 · Q139
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /NEET
  3. /Physics
  4. /Geometrical Optics
  5. /2002 · Q139

Geometrical Optics question

2002 · Q139

NEETPhysicsGeometrical OpticsMCQ+4 / −1
A bulb is located on a wall. Its image is to be obtained on a parallel wall with the help of convex lens. The lens is placed at a distance d ahead of second wall, then required focal length will be
  1. A
    only d4{d \over 4}4d​
  2. B
    only d2{d \over 2}2d​
  3. C
    more than d4{d \over 4}4d​ but less than d2{d \over 2}2d​
  4. D
    less than d4{d \over 4}4d​
View written solutionFree

Correct answer: B

Using the lens formula 1f=1v−1u{1 \over f} = {1 \over v} - {1 \over u}f1​=v1​−u1​

Given v = d, for equal size image |v| = |u| = d

By sign convention u = -d

∴\therefore∴ 1f=1d−1−d{1 \over f} = {1 \over d} - {1 \over { - d}}f1​=d1​−−d1​

⇒\Rightarrow⇒ f = d2{d \over 2}2d​

PreviousNext

More from Geometrical Optics

  • For the given incident ray as shown in figure, the condition of total internal refraction of this ray the required refractive index of prism will be Includes diagram2002 · MCQ
  • Diameter of human eye lens is 2 mm. What will be the minimum distance between two points to resolve them, which are situated at a distance of 50 meter from eye. The wavelength of light is 5000 A∘​2002 · MCQ
  • Optical fibre are based on2001 · MCQ
  • A disc is placed on a surface of pond which has refractive index 5/3. A source of light is placed 4 m below the surface of liquid. The minimum radius of disc needed so that light is not coming out is,2001 · MCQ
  • A tall man of height 6 feet, want to see his full image. Then required minimum length of the mirror will be2000 · MCQ
  • A bubble in glass slab (μ = 1.5) when viewed from one side appears at 5 cm and 2 cm from other side, then thickness of slab is2000 · MCQ
  • Rainbow is formed due to2000 · MCQ
  • For a plano convex lens (μ = 1.5) has radius of curvature 10 cm. It is silvered on its plane surface. Find focal length after silvering2000 · MCQ