sci_phy
Lenses
Chapter summary, hard words and model exam answers for Class 10 Hindi.
Free online summary and notes (Class 10 Hindi). Read it here, no PDF download needed.
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Physics · ICSE Class 10
Summary
A convex lens converges parallel rays to the principal focus. A concave lens diverges rays as if they came from its focus.
Image size, nature and position depend on object position. Ray diagrams are not decoration; they decide real/virtual and enlarged/diminished.
Power is the reciprocal of focal length in metre. Convex lenses have positive power; concave lenses have negative power.
Hard words & meanings
| principal focus | Point where rays meet or appear to meet |
| optical centre | Point through which a ray passes undeviated approximately |
| magnification | Image height divided by object height |
| dioptre | Unit of lens power |
Model exam answers, grammar & audio
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