Light reflection and refraction class 10 notes in Hindi me aapka swagat hai. Class 10 Science ke Chapter 9 “Prakash” ke yeh complete notes board exam ki taiyaari ke liye taiyaar kiye gaye hain. Is chapter me hum paravartan (reflection), goleeya darpan, apavartan (refraction), lens, lens sutra aur lens ki shakti ko simple Hindi me samjhenge — important formulas, ray diagrams ke niyam aur ek solved numerical ke saath.
Prakash Kya Hai — Light Reflection and Refraction Class 10 Notes in Hindi
Prakash urja ka ek roop hai jo humein vastuon ko dekhne me madad karta hai. Prakash hamesha seedhi rekha me chalta hai. Jab prakash kisi satah se takrata hai to do mukhya ghatnayein hoti hain — paravartan (reflection), jisme prakash wapas laut jata hai, aur apavartan (refraction), jisme ek madhyam se doosre madhyam me jane par prakash apna marg badal leta hai. Light reflection and refraction class 10 notes in Hindi ka yeh pehla hissa inhi do ghatnaon ki neenv rakhta hai.
Prakash Ka Paravartan (Reflection)
Paravartan ke do niyam board exam me pakke pooche jate hain:
- Pehla niyam: Aapatan kiran (incident ray), paravartit kiran (reflected ray) aur abhilamb (normal) — teeno ek hi tal (plane) me hote hain.
- Doosra niyam: Aapatan kon (∠i) hamesha paravartan kon (∠r) ke barabar hota hai, arthaat ∠i = ∠r.
Goleeya Darpan (Spherical Mirrors)
Avtal Darpan (Concave) aur Uttal Darpan (Convex)
Jab kisi khokhle gole ke hisse ko kaatkar uski ek satah par chamakdar polish kiya jata hai to goleeya darpan banta hai. Avtal (concave) darpan me paravartan andar ki dhansi hui satah se hota hai, jabki uttal (convex) darpan me bahar ki ubhri hui satah se. Isme teen mukhya bindu hote hain — Dhruv (P), Vakrata kendra (C) aur Focus (F). Sabse important formula yaad rakhein: R = 2f, arthaat vakrata trijya (R) focus doori (f) ki dugni hoti hai.
Pratibimb Kaise Banta Hai
Avtal (concave) darpan me vastu ki sthiti ke anusaar pratibimb:
- Vastu C se pare ho → pratibimb C aur F ke beech banta hai; ulta, vaastavik aur chhota.
- Vastu C par ho → pratibimb C par hi; ulta, vaastavik aur barabar aakaar ka.
- Vastu F aur C ke beech ho → pratibimb C se pare; ulta, vaastavik aur bada.
- Vastu F par ho → pratibimb anant (infinity) par banta hai.
- Vastu F aur dhruv (P) ke beech ho → pratibimb darpan ke peeche; seedha, aabhasi aur bada.
Uttal (convex) darpan me vastu chahe kahin bhi rakhi ho, pratibimb hamesha dhruv (P) aur focus (F) ke beech banta hai — seedha, aabhasi aur chhota. Isi khaasiyat ke kaaran gaadiyon ke side-mirror uttal darpan se bante hain taaki peeche ka wide view mile.
Darpan Sutra (Mirror Formula)
Darpan sutra hai: 1/v + 1/u = 1/f, jahan u = vastu doori, v = pratibimb doori aur f = focus doori. Aavardhan (magnification) ka sutra: m = −v/u = h’/h. Light reflection and refraction class 10 notes in Hindi me chinhon ka niyam (sign convention) zaroor yaad rakhein — naya Cartesian chinh niyam: aapatan prakash ki disha me naapi gayi dooriyan dhanaatmak (+) aur iske vipreet disha me naapi gayi dooriyan rinatmak (−) li jati hain.
Prakash Ka Apavartan (Refraction)
Jab prakash ki kiran ek pardarshi madhyam se doosre pardarshi madhyam me pravesh karti hai to uski chaal (speed) badal jati hai, jiske kaaran kiran apne seedhe marg se mud jati hai — isi ghatna ko apavartan kehte hain. Apavartan ke niyam: aapatan kiran, apavartit kiran aur abhilamb teeno ek hi tal me hote hain, aur Snell ka niyam: n = sin i / sin r. Kisi madhyam ka apavartanank (refractive index): n = c/v, jahan c nirvaat (vacuum) me prakash ki chaal hai.
Lens
Uttal (Convex) aur Avtal (Concave) Lens
Uttal (convex) lens beech me mota aur kinaron par patla hota hai — yeh aane wali samaantar kiranon ko ek bindu par abhisarit (converge) karta hai, isliye ise abhisari lens bhi kehte hain. Avtal (concave) lens beech me patla aur kinaron par mota hota hai — yeh kiranon ko faila (diverge) deta hai, isliye apshari lens kehlata hai.
Uttal lens me vastu ki alag sthitiyon par pratibimb:
- Vastu 2F se pare → pratibimb F aur 2F ke beech; ulta, vaastavik, chhota.
- Vastu 2F par → pratibimb 2F par; ulta, vaastavik, barabar aakaar ka.
- Vastu F aur 2F ke beech → pratibimb 2F se pare; ulta, vaastavik, bada.
- Vastu F par → pratibimb anant par.
- Vastu F ke andar (lens ke bahut paas) → pratibimb vastu wali taraf hi; seedha, aabhasi, bada — yahi magnifying glass ka siddhant hai.
Avtal (concave) lens me pratibimb hamesha focus (F) ke andar banta hai — seedha, aabhasi aur chhota.
Lens Sutra (Lens Formula)
Lens sutra hai: 1/v − 1/u = 1/f, aur lens ke liye aavardhan: m = v/u = h’/h. Light reflection and refraction class 10 notes in Hindi ka sabse tricky point: darpan sutra me plus (+) ka chinh hai jabki lens sutra me minus (−) — exam me yahi sabse zyada galti hoti hai, ise pakka yaad kar lein.
Lens Ki Shakti (Power of Lens)
Lens ki shakti us lens ki abhisaran ya apsharan karne ki kshamta ko darshati hai. Sutra: P = 1/f, jahan f ko metre me naapa jata hai. Shakti ka SI matrak dioptre (D) hai. Uttal (convex) lens ki shakti dhanaatmak (+D) aur avtal (concave) lens ki shakti rinatmak (−D) hoti hai. Jaldi calculate karne ka shortcut: P = 100/f, jab f centimetre me diya ho.
Numerical Ka Example (Solved)
Prashn: Ek avtal (concave) darpan ki focus doori 15 cm hai. Ek vastu darpan se 20 cm ki doori par rakhi hai. Pratibimb ki sthiti aur aavardhan gyat karein.
Hal (step-by-step):
- Diya hai: f = −15 cm, u = −20 cm (naya Cartesian chinh niyam ke anusaar).
- Darpan sutra: 1/v + 1/u = 1/f → 1/v = 1/f − 1/u = 1/(−15) − 1/(−20) = −1/15 + 1/20 = (−4 + 3)/60 = −1/60.
- Isliye v = −60 cm — pratibimb darpan ke saamne 60 cm doori par banega; vaastavik aur ulta.
- Aavardhan m = −v/u = −(−60)/(−20) = −3 — arthaat pratibimb vastu se 3 guna bada hai.
Yaad Rakhne Wale Points
- R = 2f — vakrata trijya hamesha focus doori ki dugni hoti hai.
- Uttal (convex) darpan me pratibimb hamesha seedha, aabhasi aur chhota banta hai.
- Formulas lagate samay SI units (metre) ka dhyaan rakhein; lens ki power ke liye shortcut P = 100/f (f in cm).
- Board exam me ray diagram saaf aur label ke saath banayein — bina diagram ke poore number milna mushkil hai.
- Light reflection and refraction class 10 notes in Hindi ka golden rule: darpan sutra (1/v + 1/u = 1/f) aur lens sutra (1/v − 1/u = 1/f) ke chinh ka antar kabhi na bhoolein.
Class 10 Science ke aur chapter-wise notes ke liye padhein: Bijli Chapter Class 10 Notes Hindi aur hamara Study Notes section. NCERT ki official book ncert.nic.in se free me download kar sakte hain.