Geometrical Optics

A green light is incident from the water to the air - water interface at the critical angle $\left( \theta \right)$. Select the correct statement.

Which of the following statement is correct?

A convex lens of focal length $40 \mathrm{~cm}$ forms an image of an extended source of light on a photoelectric cell. A current I is produced. The lens is replaced by another convex lens having the same diameter but focal length $20 \mathrm{~cm}$. The photoelectric current now is :

A biconvex lens of refractive index 1.5 has a focal length of $20 \mathrm{~cm}$ in air. Its focal length when immersed in a liquid of refractive index 1.6 will be:

To determine refractive index of glass slab using a travelling microscope, minimum number of readings required are :

Light travels in two media $M_{1}$ and $M_{2}$ with speeds $1.5 \times 10^{8} \mathrm{~ms}^{-1}$ and $2.0 \times 10^{8} \mathrm{~ms}^{-1}$ respectively. The critical angle between them is :

A plano convex lens of refractive index $1.5$ and radius of curvature $30$ $cm$. Is silvered at the curved surface. Now this lens has been used to form the image of an object. At what distance from this lens an object be placed in order to have a real image of size of the object

A thin glass (refractive index $1.5$) lens has optical power of $-5$ $D$ in air. Its optical power in a liquid medium with refractive index $1.6$ will be

Two lenses of power $-15$ $D$ and $+5$ $D$ are in contact with each other. The focal length of the combination is

In an optics experiment, with the position of the object fixed, a student varies the position of a convex lens and for each position, the screen is adjusted to get a clear image of the object. A graph between the object distance $u$ and the image distance $v,$ from the lens, is plotted using the same scale for the two axes. A straight line passing through the origin and making an angle of ${45^ \circ }$ with the $x$-axis meets the experimental curve at $P.$ The coordinates of $P$ will be :

An object $2.4$ $m$ in front of a lens forms a sharp image on a film $12$ $cm$ behind the lens. A glass plate $1$ $cm$ thick, of refractive index $1.50$ is interposed between lens and film with its plane faces parallel to film. At what distance (from lens) should object shifted to be in sharp focus of film?

Diameter of a plano-convex lens is $6$ $cm$ and thickness at the center is $3mm$. If speed of light in material of lens is $2 \times {10^8}\,m/s,$ the focal length of the lens is

A thin convex lens made from crown glass $\left( {\mu = {3 \over 2}} \right)$ has focal length $f$. When it is measured in two different liquids having refractive indices ${4 \over 3}$ and ${5 \over 3},$ it has the focal lengths ${f_1}$ and ${f_2}$ respectively. The correct relation between the focal lengths is :

To find the focal length of a convex mirror, a student records the following data : .tg {border-collapse:collapse;border-spacing:0;} .tg td{font-family:Arial, sans-serif;font-size:14px;padding:10px 5px;border-style:solid;border-width:1px;overflow:hidden;word-break:normal;border-color:black;} .tg th{font-family:Arial, sans-serif;font-size:14px;font-weight:normal;padding:10px 5px;border-style:solid;border-width:1px;overflow:hidden;word-break:normal;border-color:black;} .tg .tg-wrg0{font-size:22px;text-align:center;vertical-align:top} .tg .tg-wv9z{font-size:22px;text-align:center} Object Pin Convex Lens Convex Mirror Image Pin 22.2 cm 32.2 cm 45.8 cm 71.2 cm The focal length of the convex lens is f₁ and that of mirror is f₂. Then taking index correction to be negligibly small, f₁ and f₂ are close to :

In an experiment a convex lens of focal length 15 cm is placed coaxially on an optical bench in front of a convex mirror at a distance of 5 cm from it. It is found that an object and its image coincide, if the object is placed at a distance of 20 cm from the lens. The focal length of the convex mirror is :

A diverging lens with magnitude of focal length 25 cm is placed at a distance of 15cm from a converging lens of magnitude of focal length 20cm. A beam of parallel light falls on the diverging lens. The final image formed is:

A convergent doublet of separated lenses, corrected for spherical aberration, has resultant focal length of 10 cm. The separation between the two lenses is $2$ cm. The focal lengths of the component lenses are :

A plano-convex lens (focal length f₂, refractive index $\mu$₂, radius of curvature R) fits exactly into a plano-concave lens (focal length f₁, refractive index $\mu$₁, radius of curvature R). Their plane surfaces are parallel to each other. Then, the focal length of the combination will be :

A convex lens of focal length 20 cm produces images of the same magnification 2 when an object is kept at two distances x₁ and x₂ (x₁ > x₂) from the lens. The ratio of x₁ and x₂ is :-