Image in Thin Lens by Ray Tracing

Q.

For a converging lens, if the object is placed between $2F_1$ and $F_1$ the image will be formed.

1. Beyond $2F_2$

2. Between $F_2$ and $2F_2$

3. Anywhere

4. Can't comment

Q. A point object $O$ is placed on the principal axis of a convex lens of focal length $20\text{cm}$ at a distance of $40\text{cm}$ to the left of it. The diameter of the lens is $10\text{cm}$. If the eye is placed $60\text{cm}$ to the right of the lens at a distance $h$ below the principal axis, then the maximum value of $h$ to see the image is $x\text{cm}$ will be . Find the value of $2x$.

Q.

A screen is placed at a distance 40 cm away from an illuminated object. A converging lens is placed between the source and the screen and it is attempted to form the image of the source on the screen. If no position could be found, the focal length of the lens

1. Must be less than 10 cm

2. Must be greater than 10 cm

3. Must not be greater than 20 cm

4. Must not be less than 10 cm

Q.

An object of length 2.0 cm is placed perpendicular to the principal axis of a convex lens of focal length 12 cm. Find the size of the image if the object is at a distance of 8.0 cm from the lens.

1. 8 cm

2. 4 cm

3. 6 cm

4. 10 cm

Q.

A pin of length 2.00 cm is placed perpendicular to the principal axis of a converging lens. An inverted image of size 1.00 cm is formed at a distance of 40.0 cm from the pin. Find the focal length of the lens and its distance from the pin.

1. $\frac{40}{3}cm$
   

2. $\frac{20}{3}cm$

3. $\frac{60}{3}cm$

4. $\frac{80}{3}cm$

Q.

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 distace d between them. If a parallel beam of light falling on A leaves B as a parallel beam, then d is equal to
(IIT-JEE 1985)

1. 10 cm

2. zero

3. 5 cm

4. 15 cm

Q.

An object is placed at a distance of $\frac{f}{2}$ from a convex lens. The image will be formed:

1. At $-f$, virtual and double its size.

2. At $-2f$, virtual and erect.

3. At $f$, real and inverted.

4. At $2f$, real and erect.

Q. A point object O is placed on the principal axis of a convex lens of focal length 20 cm at a distance of 40 cm to the left of it. The diameter of the lens is 10 cm. If the eye is placed 60 cm to the right of the lens at a distance h below the principal axis, then the maximum value of h to see the image will be

1. 0
2. 5 cm
3. 2.5 cm
4. 10 cm

Q. The sun's diameter is $1.4\times {10}^{9}m$ and its distance from the earth is ${10}^{11}m.$ The diameter of its image, formed by a convex lens of focal length 2m will be

1. 0.7 cm
2. 1.4 cm
3. 2.8 cm
4. Zero (i.e. point image)

Q. A thin lens has focal length f and aperture radius r. It forms an image of intensity I. Now the central part of the aperture upto $\frac{r}{2}$ is blacked by an opaque material. The focal length and intensity of image will be

1. $\frac{f}{2}\&\frac{I}{2}$
2. $f\&\frac{I}{4}$
3. $\frac{3f}{4}\&\frac{I}{2}$
4. $f\&\frac{3I}{4}$