NCERT Solutions for Class 7th Science
Chapter 15. Light
- Light travels along straight lines.
- Mirror changes the direction of light This change of direction by a
mirror is called reflection of light.
- In an image formed by a mirror, the left side of the object is seen on the right side in the image, and right side of the object appears to be on the left side in the image.
- If the reflecting surface of a spherical mirror is concave, it is called a concave mirror.
- If the reflecting surface is convex, then it is a convex mirror.
- An image formed on a screen is called a real image.
- The image formed by a plane mirror could not be obtained on a screen. Such an image is called a virtual image.
- Concave mirror form a real image.
- Image formed by a convex mirror is erect, virtual and smaller in size
than the object.
- Those lenses which feel thicker in the middle than at the edges are convex lenses.
- Those which feel thinner in the middle than at the edges are concave lenses.
- A concave lens always forms erect, virtual and smaller image than the
- When seven colours of rainbow pasting on the disk in their order rotates in daylight it seems white. Such disk is generally known as Newton’s disk.
- White light is composed of seven colours.