Lens

Interactive Feed

JEE Advanced 1985

LEVELJEE Main

A convex lens $A$ of focal length $20 cm$ and a concave lens $B$ of focal length $5 cm$ are kept along the same axis with a distance $d$ between them. If a parallel beam of light falling on $A$ leaves $B$ as parallel beam, then $d$ is equal to ...... cm.

JEE Advanced 1999

LEVELJEE Main

A concave lens of glass, refractive index 1.5 has both surfaces of same radius of curvature $R$ . On immersion in a medium of refractive index 1.75, it will behave as a

(A)

convergent lens of focal length

3.5 R

(B)

convergent lens of focal length

3.0 R

(C)

divergent lens of focal length

3.5 R

(D)

divergent lens of focal length

3.0 R

JEE Advanced 2010

LEVELJEE Main

The focal length of a thin biconvex lens is $20 cm$ . When an object is moved from a distance of $25 cm$ in front of it to $50 cm$ , the magnification of its image changes from $m_{25}$ to $m_{50}$ . The ratio $\frac{m _{25}}{m _{50}}$ is

JEE Advanced 2015

LEVELJEE Advanced

Consider a concave mirror and a convex lens (refractive index $= 1.5$ ) of focal length $10 cm$ each, separated by a distance of $50 cm$ in air (refractive index $= 1$ ) as shown in the figure. An object is placed at a distance of $15 cm$ from the mirror. Its erect image formed by this combination has magnification $M_{1}$ . When the set-up is kept in a medium of refractive index $7/6$ , the magnification becomes $M_{2}$ . The magnitude $\frac{M _{2}}{M _{1}}$ is

JEE Main 1997

LEVELJEE Main

An eye specialist prescribes spectacles having combination of convex lens of focal length $40 cm$ in contact with a concave lens of focal length $25 cm$ . The power of this lens combination in diopters is

(A)

+ 1.5

(B)

- 1.5

(C)

+ 6.67

(D)

- 6.67

LEVELJEE Main

Two thin lenses, when in contact, produce a combination of power + 10 D. When they are 0.25 m apart, the power reduces to + 6 D. The focal length of the lenses are ...... m and ...... m.

JEE Advanced 2014

LEVELJEE Main

Four combinations of two thin lenses are given in Column I. The radius of curvature of all curved surfaces is $r$ and the refractive index of all the lenses is $1.5$ . Match lens combinations in Column I with their focal length in Column II and select the correct answer using the codes given below the lists.

List-I

List-II

(1)

2 r

(2)

\frac{r}{2}

(3)

- r

(4)

r

JEE Advanced 2004

LEVELJEE Advanced

An object is approaching a thin convex lens of focal length $0.3 m$ with a speed of $0.01 m/s$ . Find the magnitudes of the rates of change of position and lateral magnification of image when the object is at a distance of $0.4 m$ from the lens.

LEVELJEE Advanced

A pin is placed 10 cm in front of a convex lens of focal length 20 cm and made of a material of refractive index 1.5. The convex surface of the lens farther away from the pin is silvered and has a radius of curvature of 22 cm. Determine the position of the final image. Is the image real or virtual?

JEE Advanced 1979

LEVELJEE Advanced

The radius of curvature of the convex face of a planoconvex lens is 12 cm and its $μ = 1.5$ . (a) Find the focal length of the lens. The plane face of the lens is now silvered. (b) At what distance from the lens will parallel rays incident on the convex surface converge ? (c) Sketch the ray diagram to locate the image, when a point object is placed on the axis 20 cm from the lens. (d) Calculate the image distance when the object is placed as in (c)

LEVELJEE Main

A real image of a distant object is formed by a plano-convex lens on its principal axis. Spherical aberration

(A)

is absent

(B)

is smaller if the curved surface of the lens faces the object

(C)

is smaller if the plane surface of the lens faces the object

(D)

is the same whichever side of the lens faces the object

JEE Advanced 1993

LEVELJEE Advanced

Two thin convex lenses of focal lengths $f_{1}$ and $f_{2}$ are separated by a horizontal distance $d$ (where $d < f_{1}$ , $d < f_{2}$ ) and their centres are displaced by a vertical separation $Δ$ as shown in the figure. Taking the origin of coordinates, $O$ , at the centre of the first lens, the $x$ and $y$ -coordinates of the focal point of this lens system, for a parallel beam of rays coming from the left, are given by

(A)

x = \frac{f _{1} f _{2}}{f _{1} + f _{2}}, y = Δ

(B)

x = \frac{f _{1} ( f _{2} + d )}{f _{1} + f _{2} - d}, y = \frac{Δ}{f _{1} + f _{2}}

(C)

x = \frac{f _{1} f _{2} + d ( f _{1} - d )}{f _{1} + f _{2} - d}, y = \frac{Δ ( f _{1} - d )}{f _{1} + f _{2} - d}

(D)

x = \frac{f _{1} f _{2} + d ( f _{1} - d )}{f _{1} + f _{2} - d}, y = 0

LEVELJEE Main

A convex lens is in contact with concave lens. The magnitude of the ratio of their focal length is $\frac{3}{2}$ . Their equivalent focal length is $30 cm$ . What are their individual focal lengths ?

(A)

- 75, 50

(B)

- 10, 15

(C)

75, 50

(D)

- 15, 10

LEVELJEE Main

A convex lens of focal length 40 cm is in contact with a concave lens of focal length 25 cm. The power of the combination is

A biconvex lens of focal length $f$ forms a circular image of radius $r$ of sun in focal plane. Then which option is correct ?

(A)

π r^{2} \propto f

(B)

π r^{2} \propto f^{2}

(C)

If lower half part is convered by black sheet, then area of the image is equal to

π r^{2} /2

(D)

f

is doubled, intensity will increase

JEE Advanced 2000

LEVELJEE Advanced

A convex lens of focal length 15 cm and a concave mirror of focal length 30 cm are kept with their optic axis $P Q$ and $R S$ parallel but separated in vertical direction by 0.6 cm as shown. The distance between the lens and mirror is 30 cm. An upright object $A B$ of height 1.2 cm is placed on the optic axis $P Q$ of the lens at a distance of 20 cm from the lens. If $A^{'} B^{'}$ is the image after refraction from the lens and the reflection from the mirror, find the distance of $A^{'} B^{'}$ from the pole of the mirror and obtain its magnification. Also locate positions of $A^{'}$ and $B^{'}$ with respect to the optic axis $R S$ .

LEVELJEE Main

Spherical aberration in a thin lens can be reduced by

(A)

using a monochromatic light

(B)

using a doublet combination

(C)

using a circular annular mark over the lens

(D)

increasing the size of the lens

JEE Advanced 2013

LEVELJEE Main

The image of an object, formed by a plano-convex lens at a distance of $8 m$ behind the lens, is real and is one-third the size of the object. The wavelength of light inside the lens is $2/3$ times the wavelength in free space. The radius of the curved surface of the lens is

(A)

1 m

(B)

2 m

(C)

3 m

(D)

6 m

LEVELJEE Advanced

The graph between object distance $u$ and image distance $v$ for a lens is given below. The focal length of the lens is

(A)

5 \pm 0.1

(B)

5 \pm 0.05

(C)

0.5 \pm 0.1

(D)

0.5 \pm 0.05

LEVELJEE Main

A diminished image of an object is to be obtained on a screen 1.0 m from it. This can be achieved by placing

(A)

a plane mirror

(B)

a convex mirror of suitable focal length

(C)

a convex lens of focal length less than 0.25 m

(D)

a concave lens of suitable focal length

JEE Advanced 2000

LEVELJEE Main

A hollow double concave lens is made of very thin transparent material. It can be filled with air or either of two liquids $L_{1}$ or $L_{2}$ having refracting indices $n_{1}$ and $n_{2}$ respectively ( $n_{2} > n_{1} > 1$ ). The lens will diverge a parallel beam of light if it is filled with

(A)

air and placed in air

(B)

air and immersed in

L_{1}

(C)

L_{1}

and immersed in

L_{2}

(D)

L_{2}

and immersed in

L_{1}

JEE Advanced 2010

LEVELJEE Advanced

A biconvex lens of focal length 15 cm is in front of a plane mirror. The distance between the lens and the mirror is 10 cm. A small object is kept at a distance of 30 cm from the lens. The final image is

(A)

virtual and at a distance of 16 cm from the mirror

(B)

real and at a distance of 16 cm from the mirror

(C)

virtual and at a distance of 20 cm from the mirror

(D)

real and at a distance of 20 cm from the mirror

JEE Advanced 1996

LEVELJEE Advanced

A thin plano-convex lens of focal length $f$ is split into two halves. One of the halves is shifted along the optical axis. The separation between object and image planes is $1.8 m$ . The magnification of the image formed by one of the half lens is $2$ . Find the focal length of the lens and separation between the halves. Draw the ray diagram for image formation.

JEE Advanced 1979

LEVELJEE Main

What is the relation between the refractive indices $μ_{1}$ and $μ_{2}$ ? If the behaviour of light rays is as shown in the figure.

LEVELJEE Main

A converging lens is used to form an image on a screen. When the upper half of the lens is covered by an opaque screen

* Multiple Correct Options

(A)

half of the image will disappear

(B)

complete image will be formed

(C)

intensity of the image will increase

(D)

intensity of the image will decrease

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } A concave lens of glass, refractive index 1.5 has both surfaces of same radius of curvature R. On immersion in a medium of refractive index 1.75, it will behave as a

Two thin lenses, when in contact, produce a combination of power + 10 D. When they are 0.25 m apart, the power reduces to + 6 D. The focal length of the lenses are ...... m and ...... m.

List-I

List-II

A pin is placed 10 cm in front of a convex lens of focal length 20 cm and made of a material of refractive index 1.5. The convex surface of the lens farther away from the pin is silvered and has a radius of curvature of 22 cm. Determine the position of the final image. Is the image real or virtual?

A real image of a distant object is formed by a plano-convex lens on its principal axis. Spherical aberration

A convex lens of focal length 40 cm is in contact with a concave lens of focal length 25 cm. The power of the combination is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } A biconvex lens of focal length f forms a circular image of radius r of sun in focal plane. Then which option is correct ?

Spherical aberration in a thin lens can be reduced by

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The graph between object distance u and image distance v for a lens is given below. The focal length of the lens is

A diminished image of an object is to be obtained on a screen 1.0 m from it. This can be achieved by placing

A biconvex lens of focal length 15 cm is in front of a plane mirror. The distance between the lens and the mirror is 10 cm. A small object is kept at a distance of 30 cm from the lens. The final image is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } What is the relation between the refractive indices μ1​ and μ2​ ? If the behaviour of light rays is as shown in the figure.

A converging lens is used to form an image on a screen. When the upper half of the lens is covered by an opaque screen

A concave lens of glass, refractive index 1.5 has both surfaces of same radius of curvature $R$ . On immersion in a medium of refractive index 1.75, it will behave as a

A biconvex lens of focal length $f$ forms a circular image of radius $r$ of sun in focal plane. Then which option is correct ?

The graph between object distance $u$ and image distance $v$ for a lens is given below. The focal length of the lens is

What is the relation between the refractive indices $μ_{1}$ and $μ_{2}$ ? If the behaviour of light rays is as shown in the figure.