Question

Across
4. A convex lens is _____ lens
6. An image which can be obtained on a screen
Down
1. A concave lens is _____ lens
2. An image which cannot be obtained on a screen
3. Any polished or a shining surface acts as a _______
5. One of the rainbow colours

Answer 1

$\bf\huge{Answer :}$

Across :

4. A convex lens is a converging lens.

6. An image that can be obtained on a screen. - real

Down :

1. A concave lens is a diverging lens.

2. An image that cannot be obtained on a screen. virtual

3. Any polished or shining surface acts as a mirror.

5. One of the rainbow colors. - Yellow

$\bf\huge{ Additional\: information }$

Concave mirror: It is a spherical mirror with an outwards curved reflecting surface. It is also known as a diverging mirror.

• Nature of image - real and inverted.

Uses of the concave mirror -

• Concave mirrors are used in vehicles and headlights.
• Concave mirrors are used in the base of a microscope.

Convex mirror - Convex mirror is a mirror that is thicker at the center and thinner at its corner. It is also known as a converging mirror.

• Nature of image - virtual and erect.

Uses of the convex mirror -

• It is used in projectors.
• It is also used in the lens of cameras for a clear image.
• It is also used in spectacles and sunglasses.

White light - White light is made up of seven shades which can be remembered by the acronym VIBGYOR.

• The VIBGYOR is also named a spectrum.

• Isaac Newton was the first person who used a glass prism to obtain the spectrum of light.

• $\bf\purple{V}$ - Violet
• $\bf\blue{I}$ - Indigo
• $\bf\blue{B}$ - Blue
• $\bf\green{G}$ - Green
• $\bf\orange{Y}$ - Yellow
• $\bf\orange{O}$ - orange
• $\bf\red{R}$ - Red

Answer 2

Answer:

${\large{\bold{\purple{\underline{\leadsto\: ACCROSS\: :-}}}}}$

4) A convex lens is converging lens.

6) An image which can be obtained on a screen is called real image.

$\rule{150}{2}$

${\large{\bold{\purple{\underline{\leadsto\: DOWN\: :-}}}}}$

1) A concave lens is diverging lens.

2) An image which cannot be obtained on a screen is called virtual image.

3) Any polished or a shining surface acts as a mirror.

5) One of the rainbow colours Orange.

$\rule{300}{2}$

EXTRA INFORMATION :-

$\longmapsto$ Spherical Mirror :

• A spherical mirror is a reflecting surface which is a part of a hollow sphere.

There are two types of spherical mirror :

• Concave spherical mirror
• Convex spherical mirror

$\longmapsto$ Pole :

• The centre point P of curvature of the spherical mirror is called it's pole.

$\longmapsto$ Principal Axis :

• The principal axis of a spherical mirror is a straight line obtained by connecting the centre of curvature and the pole of the spherical mirror.

$\longmapsto$ Centre of Curvature :

• The centre of curvature of a spherical mirror is the centre of the hollow sphere of which the mirror is a part.

$\longmapsto$ Radius of Curvature :

• The radius of the hollow sphere of which this spherical mirror is a part is called radius of curvature.