Mirror Formula

Q. A concave mirror of focal length $10\text{cm}$ produces an image which can be obtained on the screen. If the image size is four times the size of the object, the distance of object from the pole of the mirror is

1. $10.5\text{cm}$
2. $12.5\text{cm}$
3. $11.5\text{cm}$
4. $13.5\text{cm}$

Q. A thin rod of length $\frac{f}{3}$, where $f$ is focal length, lies along the axis of a concave mirror. One end of its magnified image touches an end of the rod. The length of the image will be

1. $0.5f$
2. $1.5f$
3. $2.5f$
4. $3.5f$

Q. An object$\left(O\right)$ is placed at a distance $20\text{cm}$ from a convex mirror. If a plane mirror is also kept at a distance of $12\text{cm}$ from the same object as shown, image$\left(I\right)$ formed by plane mirror is at the same point at which image is produced by the convex mirror. The focal length of the convex mirror is

1. $5\text{cm}$
2. $6\text{cm}$
3. $7\text{cm}$
4. $8\text{cm}$

Q. At what distance a boy should stand from a convex mirror of focal length $2.5\text{m}$, such that his image has a height equal to half the original height?

1. $2.5\text{m}$
2. $3.5\text{m}$
3. $4.5\text{m}$
4. $5.5\text{m}$

Q. An object$\left(O\right)$ is placed at a distance $20\text{cm}$ from a convex mirror. If a plane mirror is also kept at a distance of $12\text{cm}$ from the same object as shown, image$\left(I\right)$ formed by plane mirror is at the same point at which image is produced by the convex mirror. The focal length of the convex mirror is

1. $5\text{cm}$
2. $6\text{cm}$
3. $7\text{cm}$
4. $8\text{cm}$

Q.

In an experiment of find the focal length of a concave mirror a graph is drawn between the magnitudes of u and v. The graph looks like
[AIIMS 2003]

1. 
2. 
3. 
4. 

Q. Find the distance and nature of the image formed by the concave mirror as shown in the figure.

1. $-\frac{40}{3}\text{cm}$, Real image
2. $-\frac{40}{3}\text{cm}$, Virtual image
3. $+\frac{40}{3}\text{cm}$, Real image
4. $+\frac{40}{3}\text{cm}$, Virtual image

Q.

Draw a ray diagram to illustrate the formation of an image by a concave mirror when the object is placed at the centre of curvature.

Q. A convex mirror has a focal length $f$. A real object placed at a distance $f$ in front of it from the pole, produces an image at

1. $2f$
2. $\frac{f}{2}$
3. $f$
4. $\infty$

Q.

Statement I : The formula connecting u, v and f for a spherical mirror is valid only for the mirrors whose sizes are very small as compared to their radii of curvature.

Statement II : Laws of reflection are strictly valid for plane surfaces, but not for larger spherical surfaces. [ IIT JEE 2007 ]

1. Both the statements are correct and statement II infers to Statement I
2. Both the statements are correct but Statement II doesn’t infer to Statement I
3. Statement I is correct but Statement II is incorrect
4. Statement I is incorrect but Statement II is correct

Q. Find the position of the final image of the object $O$ after three successive reflections taking first reflection on $m_1$.

1. $12.5\text{cm}$ in front of mirror $m_1$.
2. $10\text{cm}$ in front of mirror $m_1$.
3. $12.5\text{cm}$ in front of mirror $m_2$.
4. $10\text{cm}$ in front of mirror $m_2$.

Q. Consider the following system. Assuming that the first image is formed after reflection from mirror $M_1$, the $x-$co-ordinate of the final image formed by reflection from the mirror $M_2$, if $P_2$ is taken as origin will be

1. $\frac{-300}{23}\text{cm}$
2. $\frac{-300}{32}\text{cm}$
3. $\frac{+300}{23}\text{cm}$
4. $\frac{+300}{32}\text{cm}$

Q. Two concave mirrors are placed $40\text{cm}$ apart and are facing each other. A point object lies between them at a distance $12\text{cm}$ from the mirror $M-1$. Find the location of the final image formed after two reflections, first at $M-1$ and second at $M-2$.

1. $\frac{60}{7}\text{cm}$ left of $M-2$
2. $\frac{60}{7}\text{cm}$ right of $M-2$
3. $\frac{60}{7}\text{cm}$ right of $M-1$
4. $\frac{60}{7}\text{cm}$ left of $M-1$

Q. At what distance a boy should stand from a convex mirror of focal length $2.5\text{m}$, such that his image has a height equal to half the original height?

1. $2.5\text{m}$
2. $3.5\text{m}$
3. $4.5\text{m}$
4. $5.5\text{m}$

Q. Consider a sphere of radius $R$ exposed to radiation of intensity $I$ as shown in figure. If surface of sphere is partially reflecting with reflection coefficient is $0.3$, then radiation force experienced is

1. $\frac{1.3\pi R^{2}I}{c}$
2. $\frac{\pi R^{2}I}{c}$
3. $\frac{0.3\pi R^{2}I}{c}$
4. $\frac{1.7\pi R^{2}I}{c}$

Q. Find the distance and nature of the image formed by the concave mirror as shown in the figure.

1. $-\frac{40}{3}\text{cm}$, Real image
2. $-\frac{40}{3}\text{cm}$, Virtual image
3. $+\frac{40}{3}\text{cm}$, Real image
4. $+\frac{40}{3}\text{cm}$, Virtual image

Q. A person looks at his image, which is 3 times the original size, in a mirror. If radius of curvature of the mirror is 36 cm, find his distance from the mirror?

1. 12 cm
2. 18 cm
3. 6 cm
4. 4.5 cm

Q. Find the position and nature of the image formed by the concave mirror of focal length $20\text{cm}$, if the object $O$ is placed at a distance $30\text{cm}$ from the pole.

1. $-60\text{cm}$, Virtual image
2. $+60\text{cm}$, Real image
3. $-60\text{cm}$, Real image
4. $+60\text{cm}$, Virtual image