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Pinhole Camera, Periscope aur Kaleidoscope

Class 7 Science · Chapter 11: Roshni: Chhaaya aur Paraavartan · NCERT Curiosity section 11.7–11.8

Seekho

Halke andhere kamre mein Zoya chhote chhed wale card ke aage mombatti rakhti, peechhe screen. Screen par lau ka pratibimb, par ulta! Lau ke upar se roshni seedhe chhed se neeche girti; neeche se upar. Ye pinhole camera hai.

Wo ek-doosre mein khiskne wale do dibbon se banaate: bade dibbe mein pinhole, chhote mein tracing paper ki screen. Dhoop wale ped ki or karne par rangeen, ulta pratibimb. Samtal darpan ka pratibimb paarshv ulta par ulta nahi; pinhole camera ka pratibimb ulta.

Z-aakaar nali ke siron par do samtal darpan periscope banaate, jisse deewaar ya bheed ke upar dekh sakte; pandubbi aur bunker ke sainik inhe use karte. Nali mein tikon mein jude teen darpan, ek sire par choodi ke tukde, kaleidoscope banaate: pratibimbon ke pratibimb har baar ghumaane par naya pattern.

Explore: kaunsa upkaran?

  1. Har vivaran sort karo.

Yaad rakho

  • Pinhole camera ulta pratibimb banaata kyunki roshni seedhi chalti.
  • Periscope do darpan; kaleidoscope teen darpan se pattern.

Quick check

Pinhole camera ka pratibimb kaisa dikhta?

  1. upside down
  2. erect and the same
  3. always black
  4. invisible
Answer

upside down. Roshni seedhe chhed se, to upar-neeche badal jaate.

Socho

Pinhole camera ka chhed bahut bada karne par pratibimb ka kya?

Ek answer

Wo chamkeela par dhundhla, kyunki vastu ke har bindu ki roshni bade chhed ke kai hisson se jaakar fail jaati.

Practice

Teen levels (easy, medium, hard) ke naye sawaalon se practice karo, kuch hands-on, hints aur hal ke saath. Topic poora karne ke liye pichhle 5 mein se 4 sahi karo.