Title 7. P2C7. ভৌত আলোকবিজ্ঞান (With Solve).pdf ✅

†f.Z Av‡jvKweÁvb  Engineering Practice Sheet ............................................................................................................. 1 WRITTEN weMZ mv‡j BUET-G Avmv cÖkœvejx 1. 596 nm I 590 nm Zi1⁄2‣`‡N© ̈i Av‡jv GKK wP‡oi Dci cwZZ n‡”Q| a = 2 × 10–4 m, D = 1.5 m n‡j 1g Pi‡gi Ae ̄’v‡bi cv_©K ̈ KZ? [BUET 22-23] mgvavb: x1 = (2n + 1) D 2a = 31D 2a x2 = 32D 2a  x = x1 – x2  x = 3D 2a (1 – 2)  x = 3 × 1.5 4 × 10–4 (596 – 590) × 10–9  x = 6.75 × 10–5 m (Ans.) 2. Bqs Gi wØ-wPo cixÿvq wPo؇qi ga ̈eZ©x `~iZ¡ 0.1 mm, c`©v n‡Z wPo؇qi `~iZ¡ 2 m, Av‡jvi Zi1⁄2‣`N© ̈ 5000 A  n‡j, (K) `kg D3⁄4¡j †Wvivi `~iZ¡ wbY©q Ki| (L) `kg D3⁄4¡j †Wvivi †K.wYK `~iZ¡ wbY©q| [BUET 21-22] mgvavb: (K) x = nd a = 10  2  5000  10–10 0.1  10–3 = 0.1 m (Ans.) (L) a sin = n   = sin–1     n a = sin–1     10  5000  10–10 0.1  10–3 = 2.87 (cÖvq) (Ans.) 3. evZv‡m fvmgvb GKwU mvev‡bi wd‡j¥i Dci j¤^fv‡e 624 nm Zi‡1⁄2i Av‡jv AvcwZZ nq| wdj¥ n‡Z cÖwZdj‡bi m¤ú~Y© MVbg~jK e ̈wZPv‡ii Rb ̈ wd‡j¥i (i) me©wb¤œ Ges (ii) wØZxq me©wb¤œ cyiæZ¡ KZ? [evZv‡mi mv‡c‡ÿ wd‡j¥i cÖwZmiYvsK 1.35] [BUET 19-20] mgvavb: D‡jøwLZ experiment-wU Newton’s ring bv‡g cwiwPZ| MVbg~jK e ̈wZPv‡ii Rb ̈, 2t –  2 = n aŸsmvZ¥K e ̈wZPv‡ii Rb ̈, 2t –  2 = (2n – 1)  2 †hLv‡b t n‡”Q cyiæZ¡ (i) me©wb‡¤œi Rb ̈, n = 0  2t =  2  t = 1.15556  10–7 m (Ans.) (ii) wØZxq me©wb‡¤œi Rb ̈, n = 1  2t –  2 = n  2  1.35  t – 624  10–9 2 = 1  624  10–9  t = 3.47  10–7 m (Ans.) 4. Bqs Gi wØ-wPo cixÿvq, wØ-wPo‡K GK-wPo †_‡K 5 cm `~‡i ivLv nj| 5100 A  Zi1⁄2‣`‡N© ̈i meyR Av‡jv GK-wPo †_‡K G‡m wØ-wP‡o AvcwZZ n‡jv| GK-wPo †_‡K 205 cm `~‡i ivLv c`©vq 10 wU †Wvivi e ̈eavb 2 cm n‡j, wØ-wP‡oi ga ̈eZ©x `~iZ¡ †ei K‡iv| [BUET 18-19] mgvavb: GKwU †Wvivi e ̈eavb,  = 0.02 10 = 0.002 m  = D a  a = D  = 5100  10–10  (2.05 – 0.05) 0.002 = 5.1  10–4 m (Ans.) 5. Bqs Gi wØ-wPo cixÿvq wPo `ywUi ga ̈eZ©x `~iZ¡ 0.18 mm| wPo ̧‡jv †_‡K 90 cm `~‡i c`©vq †Kv‡bv GKwU GKeY©x Av‡jvi mvnv‡h ̈ †Wviv m„wó Kiv n‡j, hw` 3 rd D3⁄4¡j †WvivwU †K›`axq D3⁄4¡j †Wviv †_‡K 8.1 mm `~i‡Z¡ Aew ̄’Z nq, Zvn‡j Av‡jvi Zi1⁄2‣`N© ̈ †ei K‡iv| [BUET 17-18] mgvavb: x = nD a  8.1  10–3 = 3    90  10–2 0.18  10–3   = 5.4  10–7 m = 540 nm (Ans.)
2 ........................................................................................................................................  Physics 2nd Paper Chapter-7 6. Bqs Gi e ̈wZPv‡ii wØ-wPo cixÿvq 4.69  1014 Hz K¤úv‡1⁄4i jvj Av‡jv e ̈env‡ii d‡j †Wviv cÖ ̄’ 2.4  10–4 m nq| hw` 7.5  1014 Hz K¤úv‡1⁄4i bxj Av‡jv e ̈envi Kiv nq Zvn‡j †Wviv cÖ‡ ̄’i cwieZ©b KZ n‡e? [BUET 16-17] mgvavb: †Wviv cÖ ̄’, x = D 2a = c f D 2a  x  1 f  x1  f1 = x2  f2  x2 = 4.69  1014  2.4  10–4 7.5  1014 = 1.5  10–4 m †Wviv cÖ‡ ̄’i cwieZ©b = (2.4  10–4 – 1.5  10–4 ) m = 9  10–5 m (Ans.) 7. GKwU e‡Y©i Av‡jv w`‡q Av‡jvwKZ GKwU wØ-wPo cixÿvq wPoØq †_‡K wKQz `~‡i ̄’vwcZ c`©vq †Wviv cvIqv hvq| hw` c`©vwU‡K wP‡oi w`‡K 5  10–2 m miv‡bv nq Zvn‡j †Wvivi e ̈eav‡bi cwieZ©b nq 3  10–5 m| hw` wPo `y‡Uvi ga ̈eZ©x `~iZ¡ 10–3 m nq Z‡e e ̈eüZ Av‡jvi Zi1⁄2‣`N© ̈ wbY©q K‡iv| [BUET 14-15] mgvavb: †Wviv e ̈eavb,  = D a  1 – 2 = D1 a – D2 a   = D a   = a D = 3  10–5  10–3 5  10–2 = 6  10–7 m (Ans.) 8. bxj LED n‡Z wbtm„Z Av‡jv GKwU AceZ©b †MÖwUs Gi Dci j¤^fv‡e AvcwZZ nq| GB AceZ©b †MÖwUs G 25.4 mm cÖ‡ ̄’ mge ̈eav‡b 1.26  104 wU †iLv Uvbv Av‡Q| †K›`axq Aÿ n‡Z KZ wWwMÖ †Kv‡Y wØZxq Pig (second-order maxima) Drcbœ n‡e? [bxj Av‡jvi Zi1⁄2‣`N© ̈,  = 450  10–9 m] [BUET 14-15] mgvavb: 25.4 mm cÖ‡ ̄’ `vM Av‡Q = 1.26  104 wU  1 mm cÖ‡ ̄’ `vM Av‡Q = 1.26  104 25.4 wU = 496.06299 wU 1 N sin = n   = sin–1 (nN) = sin–1 (2  496.06299  450  10–6 ) = 26.5165 (Ans.) 9. evqy‡Z Bqs Gi wØ-wPo cixÿvq 6000 A  Zi1⁄2‣`‡N© ̈i Av‡jv e ̈envi Ki‡j †Wvivi e ̈eavb nq 2.0 mm| hw` mg ̄Í cixÿvhš¿wU‡K 1.33 cÖwZmvi‡1⁄4i GKwU Zi‡j Wzev‡bv nq Zvn‡j †Wvivi e ̈eavb KZ n‡e? [BUET 13-14] mgvavb: a gva ̈g †_‡K Av‡jv b gva ̈‡g †M‡j, ab = b a = a b    1  †Wviv e ̈eavb,  = D a     1  1 1 = 2 2  2 = 2  1 1.33 = 1.504 mm (Ans.) 10. Bqs Gi wØ-wPo cixÿvi 5877 A  Zi1⁄2‣`‡N© ̈i Av‡jv e ̈env‡ii Rb ̈ 92 wU cwÆ †`Lv hvq| 5461 A  Zi1⁄2‣`‡N© ̈i Av‡jv Øviv KZ msL ̈K cwÆ †`Lv hv‡e? [BUET 06-07] mgvavb: x = nD a    1 n ; hLb, D I a constant  1n1 = 2n2  n2 = 5877  92 5461 = 99 (Ans.) 11. †Kv‡bv e ̈wZPvi cixÿvq `ywU mymsMZ Av‡jvi Dr‡mi cÖve‡j ̈i AbycvZ 25 : 4| e ̈wZPvi m3⁄4vi Pig we›`y I Aeg we›`yi cÖve‡j ̈i AbycvZ wbY©q K‡iv| [BUET 05-06] mgvavb: I  a 2  I1 I2 = a 2 1 a 2 2  25 4 = a 2 1 a 2 2  a1 a2 = 5 2 a1 = 5k n‡j, a2 = 2k Pi‡gi Rb ̈ we ̄Ívi = a1 + a2 = 5k + 2k = 7k Ae‡gi Rb ̈ we ̄Ívi = a1 – a2 = 5k – 2k = 3k  Imax Imin = (a1 + a2) 2 (a1 – a2) 2 = (7k) 2 (3k) 2 = 49 : 9 (Ans.)
†f.Z Av‡jvKweÁvb  Engineering Practice Sheet ............................................................................................................ 3 12. `ywU mgeZ©b dvwj‡K mgvšÍiv‡j Ggbfv‡e ivLv n‡j †hb wØZxqwUi Av‡jvK Aÿ cÖ_gwUi Av‡jvK A‡ÿi mv‡_ 60 †Kv‡Y _v‡K| †Kv‡bv AmgewZ©Z Av‡jv‡K G m3⁄4vq GK cÖvšÍ w`‡q cvVv‡j Aci cÖv‡šÍi Av‡jvi ZxeaZv AmgewZ©Z Av‡jvi KZ ̧Y n‡e? [BUET 04-05] mgvavb: I2 = I0 2 cos2 60 = I0 2      1 2 2 = I0 8  I2 I0 = 1 8 A_©vr mgewZ©Z Av‡jvi ZxeaZv AmgewZ©Z Av‡jvi ZxeaZvi 1 8 ̧Y n‡e| (Ans.) 13. GKwU miæ †iLvwQ`a Øviv d«bndvi AceZ©b m„wói Rb ̈ †jÝ n‡Z 2 m `~‡i c`©v ivLv n‡jv| †iLv wQ‡`ai cÖ ̄’ 0.2 mm n‡j †`Lv hvq †h †K›`axq D3⁄4¡j we›`yi Dfq cv‡k¦© 5 mm `~i‡Z¡ Aeg we›`y MwVZ nq| AvcwZZ Av‡jvi •`N© ̈ wbY©q K‡iv| [BUET 03-04] mgvavb: 5 mm = 5  10–3 m 2 m c`©v wPo  tan = 5  10–3 2   = tan–1     5  10–3 2 = 0.143 a sin = n   = a sin n = 0.2  10–3 sin (0.143) 1 = 5  10–7 m (Ans.) 14. GKwU `yB w ̄øU cixÿvq cÖ_g me©wb‡¤œi †K.wYK Ae ̄’vb 0.20| w ̄øU `ywU ga ̈Kvi `~iZ¡ wbY©q K‡iv| e ̈eüZ Av‡jvi Zi1⁄2‣`N© ̈ = 5700 A  | [BUET 02-03] mgvavb: 1g me©wb¤œ ev Ae‡gi Rb ̈, a sin =     2n – 1 2   a sin (0.20) =     2  1 – 1 2  5700  10–10  a = 8.16  10–5 m (Ans.) weMZ mv‡j KUET-G Avmv cÖkœvejx 1. GKwU AceZ©b †MÖwUs Gi cÖwZ †mw›UwgUv‡i 6000 wU †iLv Av‡Q, hvnvi gva ̈‡g †mvwWqvg Av‡jvi wØZxq Pi‡gi eY©vjx cvIqv hvq| 2 wU †mvwWqvg Av‡jvi Zi1⁄2‣`N© ̈ 5890 A  Ges 5896 A  n‡j G‡`i g‡a ̈ †K.wYK `~iZ¡ KZ? [KUET 19-20] mgvavb: Pi‡gi Rb ̈, 1 N sin = n   = sin–1 (Nn)  2 – 1 = sin–1 (Nn2) – sin–1 (Nn1) = sin–1 (2  6000  5896  10–8 ) – sin–1 (2  6000  5890  10–8 ) = 0.058 (Ans.) 2. (a) Av‡jvK Kx? (b) †h wewKi‡Yi Zi1⁄2‣`N© ̈ 1.75  10–4 cm Zvi wd«‡Kv‡qwÝ ev ̄ú›`b msL ̈v wbY©q K‡iv| Av‡jvi MwZ = 3.0  1010 cms–1 | [KUET 03-04] mgvavb: (a) Av‡jv GK cÖKvi Zwor‡P.¤^Kxq Zi1⁄2| (Ans.) (b) c = f  f = c  = 3  108 1.75  10–4 = 1.71  1014 Hz (Ans.) 3. 5200 A  Zi1⁄2‣`‡N© ̈i meyR Av‡jv GKwU m~2 wPo n‡Z Bqs Gi wØ-wPo G AvcwZZ n‡”Q| 200 cm `~‡i c`©vi Dci 10wU cwÆi `~iZ¡ 4 cm| wP‡oi e ̈eavb wbY©q K‡iv| [KUET 03-04] mgvavb: x = nD a  a = nD x = 10  5200  10–10  200  10–2 4  10–2 = 2.6  10–4 m (Ans.) weMZ mv‡j RUET-G Avmv cÖkœvejx 1. 1.62 cÖwZmiv1⁄4 wewkó Kuv‡Pi †cø‡U Av‡jvK iwk¥ AvcwZZ nq| hw` cÖwZdwjZ Ges cÖwZmwiZ iwk¥ G‡K Ac‡ii mv‡_ j¤^fv‡e Ae ̄’vb K‡i Z‡e AvcZb †Kv‡Yi gvb wbY©q Ki| [RUET 19-20] mgvavb: r i  90 q i = P = mgeZ©b †KvY tanP =  P = tan–1 () = tan–1 (1.62) = 58.31 (Ans.)
4 ........................................................................................................................................  Physics 2nd Paper Chapter-7 2. †Kv‡bv AceZ©b †MÖwUs‡qi cÖwZ †mw›UwgUv‡i 6000 †iLv Av‡Q| Gi wfZi w`‡q 5896 A  Zi1⁄2‣`‡N© ̈i Av‡jv †dj‡j wØZxq Pi‡gi Rb ̈ AceZ©b †KvY †ei K‡iv| [RUET 17-18] mgvavb: 1 N sin = n   = sin–1 (nN) = sin–1 (2  6000  5896  10–8 ) = 45.03 (Ans.) [Calculation Gi myweavi Rb ̈ GB Type Math-G N Gi GK‡Ki mv‡_ wgj †i‡L  Gi GKK e ̈envi Kiv n‡q‡Q|] weMZ mv‡j CUET-G Avmv cÖkœvejx 1. 0.2 wg. wg. e ̈eavbwewkó `ywU wPo n‡Z 50 †m. wg. `~i‡Z¡ Aew ̄’Z c`©vi Dci e ̈wZPvi m3⁄4v m„wó nj| ci ̄úi `ywU D3⁄4¡j cwÆi ga ̈eZ©x `~iZ¡ 1.42 wg. wg. n‡j Av‡jvi Zi1⁄2‣`N© ̈ wbY©q K‡iv| [CUET 05-06] mgvavb: †Wviv e ̈eavb,  = D a   = a D = 2  10–4  1.42  10–3 0.5 = 5.68  10–7 m (Ans.) weMZ mv‡j BUTex-G Avmv cÖkœvejx 1. GKwU miæ w ̄øU †_‡K wbw`©ó `~i‡Z¡ GKwU c`©v ̄’vcb Kiv Av‡Q| w ̄øUwU‡K meyR Av‡jv ( = 500 nm) Øviv Av‡jvwKZ Kiv n‡j cÖ_g μ‡gi AceZ©b †KvY nq 30| AceZ©b w ̄øUwUi cÖ ̄’ wbY©q Ki| [BUTex 22-23] mgvavb: a sin = n  a = 1 × 500 × 10–9 sin 30 = 1 m (Ans.) 2. Bqs Gi wØ-wPo cixÿvq njy` e‡Y©i ( = 5.89  10–5 cm) Av‡jv e ̈envi Ki‡j c`©vq 0.1 cm cÖ‡ ̄’i cwÆ cvIqv hvq| Avevi ARvbv e‡Y©i wfbœ Zi1⁄2‣`‡N© ̈i GKwU Av‡jv e ̈envi Ki‡j c`©vq 0.08 cm cÖ‡ ̄’i cwÆ cvIqv hvq| ARvbv Av‡jvi Zi1⁄2‣`N© ̈ KZ? [BUTex 21-22] mgvavb: †Wviv cÖ ̄’, x = D 2a  x    x2 x1 = 2 1  2 = 0.08 0.1  5.89  10–7 = 4.712  10–7 m (Ans.) 3. ‘d’ cÖ ̄’wewkó w ̄øU‡K mv`v Av‡jv Øviv Av‡jvwKZ Kiv n‡jv| 5870 A  Zi1⁄2‣`‡N© ̈i njy` Av‡jvi Rb ̈ cÖ_g μ‡gi AceZ©b †KvY 30 n‡j ‘d’ KZ n‡e? [BUTex 05-06] mgvavb: 1 N sin = n  d sin = n  d = 1  5870  10–10 sin30 = 1.174  10–6 m (Ans.) MCQ weMZ mv‡j BUET-G Avmv cÖkœvejx 1. †KvbwUi Zi1⁄2‣`N© ̈ †ewk? [BUET Preli 22-23] bxj njy` Kgjv jvj DËi: jvj 2. 00 Gi gvÎv KZ? [BUET Preli 22-23] MLT–1 ML2T –1 T –1L TL–1 DËi: TL–1 3. c‡qw›Us †f±i m~Î †KvbwU? [BUET Preli 22-23] 1  ( )  B   H 1  ( )  E   H ( )  E   H 1  ( )  B   E DËi: ( )  E   H 4. GKK wP‡oi Rb ̈, 1g AÜKvi †Wvivi Rb ̈ †K.wYK `~iZ¡ KZ? [Zi1⁄2‣`N© ̈ = 5600 A  Ges wP‡oi cÖ ̄’ 5 mm] [BUET Preli 22-23] 4.417  10–3 5.417  10–3 6.417  10–3 7.417  10–3 DËi: 6.417  10–3 e ̈vL ̈v: a sin = 1     = sin–1     5600  10–10 0.005 = 6.417  10–3 5. Bqs Gi e ̈wZPv‡ii e ̈eüZ Av‡jvi Zi1⁄2‣`N© ̈ 3890 A  , wPo؇qi ga ̈eZ©x `~iZ¡ 1 mm Ges cici `yBwU †Wvivi `~iZ¡ 0.1 mm| c`©v n‡Z wP‡oi `~iZ¡ KZ? [BUET Preli 21-22] 0.257 m 0.256 m 0.258 m None DËi: None e ̈vL ̈v: x = D 2a  D = 0.1  10–3  2  10–3 3890  10–10 = 0.514 m