Mirror Formula

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

Q. The image of a square hole in a screen illuminated by light is obtained on another screen with the help of converging lens. The distance of the hole from the lens is \(40~\text{cm}\). If the area of the image is nine times that of the hole, the focal length of the lens is

Q. A converging mirror M₁, a point source S and a diverging mirror M₂ are arranged as shown in figure. The source is placed at a distance of 30 cm from M₁. The focal length of each of the mirrors is 20 cm. Consider only the images formed by a maximum of two reflections. It is found that one image is formed on the source itself. (a) Find the distance between the two mirrors. (b) Find the location of the image formed by the single reflection from M₂.
Firegu

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 U-shaped wire is placed before a concave mirror having radius of curvature 20 cm as shown in figure. Find the total length of the image.
Figure

Q. A convex mirror has a focal length $20\text{cm}$. A convergent beam tending to converge to a point $20\text{cm}$ behind the mirror on principal axis falls on it. The image is formed at

1. Infinity
2. $40\text{cm}$
3. $20\text{cm}$
4. $10\text{cm}$

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 point source S is placed midway between two converging mirrors having equal focal length f as shown in figure. Find the values of d for which only one image is formed.
Figure

Q. Focal length of a concave mirror is given by
1/f= 1/v+1/u
where u = (-20 plus minus 0.5)
v = (30 plus minus 0.1)
Calculate focal length with error limits

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 $m_2$.