Spherical Mirrors

The power of a lens $\left(P\right)$ is calculated by the formula: $P= \frac{1}{f}$, where $f$ is the focal length of the lens. A lens has a focal length of $– 0.25 \mathrm{m}$. Is it a convex lens or a concave lens? Explain your answer.

The picture shows the path of light as it travels from one medium to another.

What is medium 1 and medium 2?

A mirror magnifies the image of an object by $-1.5$ times. Which of the following is true about the image produced by the mirror?

Solar cookers contain a concave mirror. How does the concave mirror help in heating the food?

Smriti is looking at herself in a convex mirror in a science museum, standing $2 \mathrm{m}$ away from the mirror. Her image appears to be around half her actual height. Estimate the focal length of the mirror.

The diagram below shows the image of a candle, as formed through refection from a concave mirror, obtained on a screen.

How many light rays from the point P on the candle flame can be drawn to the corresponding point on the image P'?

A section of a sphere is mirrored on both sides. If the magnification of an object is $1.8$ when the section is used as a concave mirror, what is the magnification of an object at the same distance in front distance in front of the convex side? 

We might have observed that convex mirrors are used in vehicles as rearview mirrors. Convex mirrors are preferred as rearview mirrors because they always produce erect image and has large field of view compared to plane mirrors. We might have also observed the note written on rearview mirrors saying that objects appearing in the mirrors are closer than they appear. Let’s understand how far/close they look in a rearview mirror with this case study.

A car is fitted with convex mirror as a rearview mirror of radius of curvature $300 \mathrm{cm}$. If a vehicle behind the car is at $6 \mathrm{m}$ from the mirror and its height is $2 \mathrm{m}$, then the height of the vehicle appear in the mirror is

Size of a real image of an object formed by a mirror having a focal length of $20 \mathrm{cm}$ is observed to be reduced to ${\frac{1}{3}}^{\mathrm{rd}}$ of its size. At what distance the object has been placed in front of the mirror?

An object of $4 \mathrm{cm}$ high placed in front of concave mirror of focal length $20 \mathrm{cm}$ forms $8 \mathrm{cm}$ high image. Find the position of object and position of image.

An object is placed at a certain distance on the principal axis of a concave mirror. The image is formed at a distance of $30 \mathrm{cm}$ from the mirror. Find the object distance if the radius of curvature $R=15 \mathrm{cm}$.

How far should an object be from a concave mirror of radius $0.36 \mathrm{m}$ to form a real image $\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$9$}\right.$th of its size?

A ray of light directed towards the focus of the convex mirror after reflection from the mirror becomes _____.

A convex mirror is used in solar furnaces.

An object  $4 \mathrm{cm}$ high is placed at a distance of $40 \mathrm{cm}$ in front of a concave mirror of focal length $20 \mathrm{cm}$. Find the distance (in $\mathrm{cm}$) from the mirror at which a screen should placed to obtain a sharp image.

Two big mirrors A and B are fitted side by side on a wall. A man is standing at such a distance from the wall that he can see the erect image of his face in both the mirrors. When the man starts walking towards the mirrors, he finds that the size of his face in mirror A goes on increasing but that in mirror B remains the same.

A boy is standing in front of and close to a special mirror. He finds the image of his head bigger than normal, the middle part of his body of the same size, and his legs smaller than normal. The special mirror is made up of three types of mirrors in the following order from top downwards:

A mirror forms an image which is $30 \mathrm{cm}$ from an object and twice its height.

(a) Where must the mirror be situated ?

(b) What is the radius of curvature ?

(c) Is the mirror concave or convex ?

For performing an experiment, a student was asked to choose one concave mirror and one convex lens from a lot of mirrors and lens of different kinds. The correct procedure adopted by her will be:

In order to determine the focal length of a concave mirror, a student obtained a sharp image of the grill of a window in the laboratory wall on a screen. His teacher suggested that to get better result for focal length, he should focus a distant tree instead of the window grill. In which direction should the mirror be moved for this purpose so as to get a sharp image of the tree on the screen?