Type any topic from your CBSE syllabus and get it explained simply — with a diagram and a video.
Chapter 9 · Light — Reflection and Refraction
A curved mirror is just a small piece of a sphere — concave curves inward, convex curves outward, and a handful of labelled points describe both.
Move the object closer to a concave mirror and the image flips from real-and-small to virtual-and-huge — exactly at the focus, it disappears.
A convex mirror always gives the same kind of image — small, upright, and behind the mirror — no matter how far away the object is.
One formula connects object distance, image distance, and focal length for any mirror — as long as you get the plus and minus signs right.
Light bends when it crosses into a different transparent medium — that's why a straw looks broken in a glass of water.
Light bends twice going through a glass slab — once in, once out — and the two bends exactly cancel each other's angle, just shifting the ray sideways.
Refractive index is just a number that tells you how much a medium slows light down compared to air — a bigger number means a bigger bend.
A convex lens (thick in the middle) pulls light rays together; a concave lens (thin in the middle) spreads them apart.
A convex lens behaves a lot like a concave mirror — far objects give small real images, and only up close does it act as a magnifying glass.
A concave lens never changes its mind — the image is always virtual, erect, and smaller than the object, wherever you place the object.
The lens formula looks almost like the mirror formula, but with a minus sign — small difference, easy to mix up in exams.
A lens's 'power' is just 1 divided by its focal length in metres — a short focal length means a strong, high-power lens.
Chapter 10 · The Human Eye and the Colourful World
Your eye is a camera made of living tissue — here's what each part actually does.
How your eye lens changes shape to focus on things both near and far — and why it has limits.
Your eye focuses distant objects in front of the retina instead of on it — so far things blur, near things stay sharp.
Your eye focuses nearby objects behind the retina — so close-up things blur while distant ones stay clear.
As the eye ages, its power of accommodation fades — many people then need bifocal lenses.
Unlike a glass slab, a prism's slanted faces bend light sideways — that sideways bend is the angle of deviation.
White light isn't one colour — a prism splits it into seven, because each colour bends by a different amount.
Stars twinkle because Earth's shifting atmosphere keeps bending their light by tiny, changing amounts.
You see the sun about 2 minutes before it actually rises, and 2 minutes after it actually sets — atmospheric refraction again.
Air molecules scatter blue light far more than red light — that scattered blue is what fills the daytime sky.