Combination of Lens

A concave lens of focal length $30 \mathrm{cm}$ placed in contact with a plane mirror acts as a:

The lenses of power $+ 3.5 \mathrm{D}$, $+ 2.5 \mathrm{D}$ and $+ 1 \mathrm{D}$ are placed in contact with each other in an optical device. The effective power of combination of these lenses is :

Which of the following system of lens should be placed in the box P if the incident rays $I_1 and I_2$ has $I{\text{'}}_1 and I{\text{'}}_2$ as its refracted ray

Which of following system of lens should be placed in the box P if the incident rays$I_1$  and $I_2$ has$I{\text{'}}_1$  and$I{\text{'}}_2$  as its refracted ray.

A convex lens X and concave lens Y has common principle axis.

Based on diagram choose the correct statements

1. X has its Focus point at a point in between N-R.

2. Y has its one focus at M.

3. L is one of focus of convex lens X.

Ray diagram of system of mirror and rays drawn is on graph paper. Choose the appropriate option based on information given in diagram.

From the information given in the diagram, choose from which point the outgoing ray will pass finally.

From the ray diagram as shown in figure find the value of $\frac{f_1}{f_2}$, $f_1$ is focal length of convex lens and $f_2$ is focal length of concave lens.

A convex lens and concave lens placed with common principle axis. From the information in the ray diagram of system of lenses find the value of $\frac{f_1}{f_2}$

Ray diagram of incident ray I is shown in the diagram of lens-mirror system of one double convex lens and concave mirror. If all the dots are equally placed find the value of $\frac{f_k}{f_l}$ .

Find the value of ratio of $\frac{f_l}{f_k}$ where $f_k$ and $f_l$ represents the focal length of two convex rays shown in diagram. The dots are equally placed.

A pin of length 2.0 cm lies along the principal axis of a converging lens, the centre being at a distance of 11 cm from the lens. The focal length of the lens is 6 cm. Find the size of the image.

A convex lens produces a double size real image when an object is placed at a distance of 18 cm from it. Where the object should be placed to produce a triple size real image?

Which of the following statement(s) is(are) correct?

1. Power of convex lens is always +ve.

2. Power of plane mirror is zero.

3. Concave lens when placed in optical denser medium than the material behaves as converging lens.

4. Power of plano convex lens formed by dividing biconvex lens into two equal parts when placed in air is $\frac{(\mu -1)}{R}$

The general relation of focal length of a double convex lens placed in air is

A thin double convex lens has radii of curvature each of magnitude 40 cm and is made of glass with refractive index 1.65. Its focal length is

Cotyledons are also called-