Magnification by a Spherical Surface

Q. A thin equiconvex lens made of glass $(n=\frac{3}{2})$ is placed in such a way, that one surface is in contact with water $(n=\frac{4}{2})$ and another surface is in contact with air. Find focal length of setup if the rays are incident as shown. Radius of curvature $(R=30cm).$

1. $30cm$
2. $100cm$
3. $60cm$
4. $120cm$

Q.

A parallel beam of light after suffering reflection from a concave mirror returns back as ___ beam of light.

Q.

The sign of magnification by a mirror gives information about the size of the image formed by it.

1. True
2. False

Q.

Find the size of the image formed in the situation shown in figure.

1. 0.8 cm, inverted

2. 0.6 cm, inverted

3. 0.6 cm, erect

4. 0.4 cm, erect

Q.

On looking in a plane mirror, you are touching your left ear with your right hand. What would you find in your image?

Q.

In the previous question, R is:

1. Positive

2. Negative

3. Can't comment

4. Data insufficient

Q. ${\hat{n}}_1$ is the unit vector along incident ray, ${\hat{n}}_2$ along the normal to plane mirror and ${\hat{n}}_3$ is the unit vector along reflected ray direction, then which of the following must be true ?

1. ${\hat{n}}_1.{\hat{n}}_2=0$
2. $({\hat{n}}_1\times {\hat{n}}_2).{\hat{n}}_3=0$
3. $({\hat{n}}_1\times {\hat{n}}_2)\times {\hat{n}}_3=0$
4. ${\hat{n}}_1.{\hat{n}}_3=0$

Q. ${\hat{n}}_1$ is the unit vector along incident ray, ${\hat{n}}_2$ along the normal to plane mirror and ${\hat{n}}_3$ is the unit vector along reflected ray direction, then which of the following must be true ?

1. $({\hat{n}}_1\times {\hat{n}}_2)\times {\hat{n}}_3=0$
2. ${\hat{n}}_1.{\hat{n}}_3=0$
3. $({\hat{n}}_1\times {\hat{n}}_2).{\hat{n}}_3=0$
4. ${\hat{n}}_1.{\hat{n}}_2=0$

Q.

Find the size of the image formed in the situation shown in figure.

Q.

Find the size of the image formed in the situation shown in figure.

1. 0.4 cm, erect

2. 0.8 cm, inverted

3. 0.6 cm, inverted

4. 0.6 cm, erect

Q. A short linear object of length $l$ lies along the axis of a concave mirror at a distance $u$ from it. If $v$ is the distance of the image from the mirror, then the size of the image is

1. $\left(\frac{v}{u}\right)l$
2. ${\left(\frac{v}{u}\right)}^{2}l$
3. $\left(\frac{u}{v}\right)l$
4. ${\left(\frac{u}{v}\right)}^{2}l$

Q.

Find the size of the image formed in the situation shown in figure.

1. 0.8 cm, inverted

2. 0.6 cm, inverted

3. 0.6 cm, erect

4. 0.4 cm, erect

Q.

When is magnification positive or negative?