Physics · Class 8–10

Refraction of Light

See why a straw looks bent in water — light changes direction when it passes between air and glass or water.

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🧠 Remember it

Refraction of Light

Light bends when it changes medium. Into a denser medium (air→water) it bends TOWARD the normal; into a rarer medium it bends AWAY. "Denser = slower = bends toward."

🌏 In real life

A straw in a glass of water looks bent or broken at the surface — light from the straw bends as it leaves the water, fooling your eyes about where the straw really is.

📝 Quick notes

  • Refraction is the bending of light as it passes from one transparent medium into another.
  • It happens because light changes speed between media (it travels slower in a denser medium).
  • Going into a denser medium (air → glass/water): light bends toward the normal.
  • Going into a rarer medium (water → air): light bends away from the normal.

🎯 Test yourself

Why does light bend when it enters water from air?

Light slows down in the denser water, which changes its direction — it bends toward the normal.

Learn it fully — free

See the animated, step-by-step Refraction of Light lesson on Syllab

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