LESSON-19. Megnet

1. LESSON-19. Megnet

2. 5ZLRI • >,[S8=LS, V[gHLGLIZL\UDF\\\\ D[uG[8 VG[ .,[S8=MD[uG[8G] 36] DCtJ K[P VM<8ZG[8Z4 0LP;LPHGZ[8Z4 DM8Z4 8=Fg;OMD"Z4 ZL,[ .,[S8=LS A[, JU[Z[ >,[S8=F[D[uG[8LhDGF l;wWFT 5Z SFI" SZ[ K[P VFYL4 JLHI+MGM VeIF; SZTF 5C[,F D[uG[8LhD VG[ .,[S8=MD[uG[8LhD lJX[ DFlCTUFZ YJ] VtIT VFJxIS K[P • D[uG[8 sR]\\ASf V[8,[ X]\ m • V[lXIF DF.GMZDF\\\ D[uG[lXIF GFDGF XC[ZGL BF6DF\YL ;F{ 5|YD D[uG[8GL SFRL wFFT]GL XMW SZJFDF\ VFJLP VFYL VF WFT]G]\ GFD D[uG[8 50I]\P • VF 5NFY" ,MB\0G[ VFSQFL" XSTF VG[ T[G[ D]ST ZLT[ ,8SFJJFDF\ VFJ[ tIFZ[ 5MTFGL WZL p¿Z vNl1F6 lNXF TZO ZFBTFP • VFD4 R]\AS V[S 5NFY" K[P H[ ,MB\0G[ sSMAF<8 S[ lGS,G[ 56f 5MTFGL TZO VFSQM" K[P VG[ HIFZ[ T[ OZJF DF8[ D]ST CMI K[P tIFZ[ T[GL WZL p¿ZvNl1F6 lNXF TZO ZFB[ K[P

3. R]\ASGF 5|SFZM • s!f S]NZTL D[uG[8 sZf S'l+D D[uG[8 • R]\AS •  • S]NZTL S'l+D • S]NZTL D[uG[8 V[ BF6DF\YL D/TM 5NFY" K[P HIFZ[ S'l+D D[uG[8 :8L, VG[ T[GL lDz WFT]DF\YL AGFJJFDF\ VFJ[ K[P • D[uG[8 GF\ ALHL ZLT[ 56 5|SFZ 5F0L XSFI • H[D S[4 (1) :YFIL VYJF 5ZD[Gg8 D[uG[8 • (2) V:YFIL VYJF .,[S8=MD[uG[8 • :YFIL D[uG[8 5MTFGF\ R]\ASLI U]6WDM" HF/JL ZFB[ K[P :YFIL D[uG[8 :8L,4 lGS,4 V[<GLSM JU[Z[DF\YL AGFJJFDF\ VFJ[ K[P • HIFZ[ ;MO8 VFIG" sGZD ,MB\0f GF\ ;/LIF sAFZf OZT[ SM., JL\8F/L SM.,DF\YL 0FIZ[S8 SZ\8 5;FZ SZJFYL T[ 5L; D[uG[8GF\ U]6WDF"[ WZFJ[ K[P VFG[ V:YFIL VYJF .,[S8=MD[uG[8 SC[JFDF\ VFJ[ K[P

4. D[uG[8LhD G[ ,UTF 5NM • s!fR]\ASLI W=]J ov • V[S AFZ D[uG[8G[ ,MB\0GF\ E]SFDF\ AM/L ACFZ ,FJJFDF\ VFJ[ TM DF[8F EFUGM E]SM T[GF\ K[0FVMV[ AFh[,M DF,]D 50X[P VF A\G[ K[0FVMG[ W]=J SC[ K[P • AFZ D[uG[8G[ HIFZ[ D]ST ZLT[ ZC[ V[ ZLT[ ,8SFJJFDF\ VFJ[ TM T[GM V[S K[0M p¿Z lNXF TZO ZC[ K[P T[G[ p¿Z W|]J VG[ ALHM K[0M Nl1F6 lNXF TZO ZC[ K[P VFG[ GMY" 5M, SC[ K[P • sZf V[SD 5M, ov • V[SD 5M, V[8,[ V[JM 5M, H[ 5MTFGL ;FD[ ! DL8Z GF V\TZ[ D]S[,F T[JF H 5M,G[ !_ gI]8GGF\ A/YL V5FSQF"[P • s#f R]\ASLI 1F[+ ov • R]\ASGL VFH]AFH]GM lJ:TFZ H[DF\ R]\ASLI 5NFY" 5Z A/ ,FU] 50[ K[P T[ lJ:TFZG[ R]\ASLI 1M+ SC[ K[P • s$fR]\ASLI A/Z[BFVM ov • R]\ASLI A/Z[BFVM V[ SF<5lGS Z[BFVM K[P H[ R]\ASGL ACFZ p¿Z W|]J (N)DF\YL GLS/L Nl1F6 W|]J (S)TZO HFI K[P VG[ R]\ASGL V\NZ Nl1F6 W|]J (S)YL p¿Z W|]J (N)TZO HFI K[P • VFS'lTDF\ AFZ D[uG[8GL A/Z[BFVM NXF"JL K[P T[G[ R]\ASLI A/Z[BFVMGM I]lG8 J[AZ(weber) K[P • s5f R]\ASLI V1F ov • D[uG[8GF\ A[ 5M,G[ HM0TL Z[BFG[ D[uG[8LS V[S;L; (Magnetic Axis)SC[ K[P

5. D[uG[8LhD G[ ,UTF 5NM • (6) R]\ASLI T8:Y V1F ov • R]\ASLI V1FG[ ,\A Z[BFG[ R]\ASLI T8:Y V1F SC[ K[P • (7) O,S; 0[g;L8L o v • R\]ASLI A/Z[BFVMG[ ,\A V[SD 1F[+O/DF\YL 5;FZ YTF\ O,S;G[ O,S;GL WGTF O,S; 0[g;L8L (flux density)SC[ K[P • T[GF[ V[SD J[AZ 5|lT DL8Z JU" K[P T[G[ 8[;,F (tesla)YL NXF"JFI K[P T[GL ;\7F K[P • (8)A[ R]\ASGF\ W]|JM JrR[G\] A/ ov • A[ R]\ASG\F W]|JMG[ V[SALHFGL GHLS V\TZ[ ZFBJFDF\ VFJ[ TM T[ JrR[ ,FU] 50T]\ A/ T[ A\G[ 5M, :8=[gYGF\ U]6FSFZGF 5|DF6DF\ VG[ T[GF\ V\TZGF\ JU"GF\ jI:T 5|DF6DF\ CMI K[P • HIF\ o m1m2 = 5M,GL :8=[gY • d =5M,GL JrR[G]\ V\TZ • μ =DFNIDGL 5FZUdITF

6. D[uG[8LhD G[ ,UTF 5NM • (9) 5FZUdITF (Permeability):− • VD]S D8LZLV, sNFPTP ;L<JZ4 SM5Z JU[Z[f .,[S8L=S SZ\8G[ 5MTFGFDF\YL ;C[,F.YL 5;FZ YJF N[ K[P • HIFZ[ VD]S D8LZLV, sNFPTP VFIG"4 GF.S=MD JU[Z[f .,[S8L=S SZ\8G[ 5MTFGFDF\YL ;C[,F.YL 5;FZ YJF N[TF GYLP • HIFZ[ VD]S D8LZLV, sNFPTP ZAZ 5M;",[.G JU[Z[f .,[S8L=S SZ\8G[ 5MTFGFDF\YL GlCJTŸ ZLT[ 5;FZ YJF N[ K[P • 5NFY"GF 5MTFGFDF\YL SZ\8G[ 5;FZ YJF N[JFGF U]6WD"G[ Sg0S8LJL8L YL VM/BJFDF\ VFJ[ K[P • VFJL H ZLT[ 5NFY" 5MTFGFDF\ D[uG[8LS O,S;G[ V[S;ZBL ZLT[ pt5gG YJF N[TF GYLP 5NFY"GF\ 5MTFGFDF\ D[uG[8LS O,S; pt5gG SZJF N[JFGF\ U]6WD"G[ 5FZUdITF (Permeability) SC[ K[P • NFPTP ,MB\04 :8L, JU[Z[ 5NFYM"DF\ ;C[,F.YL D[uG[8LS O,S; 5[NF Y. XS[ K[P • HIFZ[ CJF4 ,FS0]\4 V[<I]DLGLID4 A|F; JU[Z[DF\YL VMKL R]\ASLI A/Z[BFVM 5;FZ Y. XS[ K[P • V[Z VYJF J[SI]DGL 5ZDLIFAL,L8LG[ Z[OZg; VYJF A[.h TZLS[ U6JFDF\ VFJ[ K[PVG[ T[G[µо YL NXF"JJFDF\ VFJ[ K[P • µо GL lS\DT4π×10ˉ7K[P • SM.56 D8LZLV,GL 5ZDLIFAL,L8LG[ µYL NXF"JJFDF\ VFJ[ K[P T[G[ V[a;M<I]8 5ZDLIFAL,L8L SC[JFDF\ VFJ[ K[P • HIFZ[ D8LZLV,GL 5ZDLIFAL,L8LG[ V[ZGL 5ZDLIFAL,L8L ;FY[ ;ZBFJJFDF\ VFJ[ V[8,[ S[4 D8LZLV,GL 5ZDLIFAL,L8L V[ZGL 5ZDLIFAL,L8L SZTF S[8,F U6L K[P T[G[ ZL,[8LJ 5ZDLIFAL,L8L (µr)YL NXF"JJFDF\ VFJ[ K[P • (10) ZL,S8g; ov • .,[S8=LS ;lS"8DF\ H[JL ZLT[ JFCS 5MTFGFDF\YL 5;FZ YTF 5|JFCGM lJZMW SZ[ T[G[ Z[hL:8g; SC[JFDF\ VFJ[ K[P T[JL ZLT[ 5MTFGFDF\ D[uG[8LS O,S; pt5gG YJFGF lJZF[W SZJFGF\ D8LZLV,GF\ U]6WD"G[ ZL,S8g; SC[ K[P

7. R]\ASGF\ U]6WDF[" • (1) VFSQF"6 ov • R\]AS4 R]\ASLI 5NFYM" H[JF S[4 ,MB\04 SMAF<84 GLS, JU[Z[G[ VFSQF"JFGM U]6WD" WZFJ[ K[P • VF XlST 5M,GL GHLS 5|A/ CMI K[P R]\AS 5MTFGFYL lJ~wW 5M,G[ 56 VFSQF"[ K[P • (2) V5FSQF"6ov • 5MTFGF H[JF 5M,G[ R]\AS V5FSQF"[ K[P • NFPTPGF[Y" 5M,(N)GF[Y" 5M,(N)G[4VG[ ;FpY 5M,(S);FpY 5M, (S) G[ V5FSQF[" K[P • (3) lNXF ;}RG ov • HIFZ[ D[uG[8G[ D]ST ZLT[ OZL XS[ V[ ZLT[ ,8SFJJFDF\ VFJ[ K[P tIFZ[ T[ 5MTFGL V1F p¿Z vNl1F6 lNXF TZO ZFB[ K[P T[GM H[ 5M, p¿Z lNXF TZO ZC[ K[P T[G[ p¿Z W|]J (North pole) (N)SC[ K[P • HM T[G[ VF l:YTLDF\YL B;[0JFDF\ VFJ[ TM 56 T[ 5MTFGL D}/ l:YTLDF\ VFJL HFI K[P • (4)5|[Z6 ov • R]\AS T[GL 5F;[ D]S[, R\]ASLI 5NFY"DF\ R]\AStJ 5|[ZJFGM U]6WD" WZFJ[ K[P

8. R]\ASGF\ U]6WDF[" • (5) A[ 5M, WZFJJFM U]6WD" ov • V[S 5M,JF/M R]\AS SNL V:TLtJ WZFJL XS[ GCLP HM V[S D[uG[8GF\ 36F\ 8]S0F SZJFDF\ VFJ[ TM NZ[S 8]S0FDF\ A[ 5M, 5[NF YFI K[P VFS'lTDF\ NXF"jIF 5|DF6[ V[S D[uG[8GF\ A[ 8]S0F VG[ NZ[SGF\ A[ 8]S0F SZJFDF\ VFJ[ TM 56 NZ[S 8]S0FDF\ A[ 5M, CMI K[P • T[JL H ZLT[ T[GF GFGF v V;\bI 8]S0F SZJFDF\ VFJ[ TM 56 NZ[SDF\ A[ 5M, CX[P • (6)R]\AStJ GFX 5FDJFGM U]6WD" ov • SF[.56 R]\ASG]\ R]\AStJ C\D[X DF8[ T[8,]\ H ZC[ V[J]\ GYLP ;DI HTF\ T[DF\ 38F0F[ YFI K[ VYJF R]\ASG[ p\RF.YL O[\SJFDF\ VFJ[ V[8,[ S[VOF/JFDF\ VFJ[ VYJF CYM0FYL 8L5JFDF\ VFJ[ VYJF UZDL VF5JFDF\ VFJ[ TM R]\ASTJ VMK] YFI K[P VYJF TM GFX 5FD[ K[P • (7) ;\T'%TFGM U]6WD" ov • SM.56 R]\AS VD]S CNYL JWFZ[ R]\AStJ 5|F%T SZL XS[ GCL\P VFG[ ;\T'%TF (Saturation) SC[ K[P

9. .,[S8=M.g0SXG • SM.,DF\YL 5;FZ YTF 5|JFCG[ ,LW[ pt5gG YT]\ R]\ASLI 1M+ ov • CJ[ ;LWF JFCSG[ UM/ JF/LV[ VG[ T[DF\YL 5|JFC 5;FZ SZLV[P Sg0S8ZDF\YL 5;FZ YTF\ 5|JFCG[ ,LW[ R\]ASLI 1M+ pt5gG YX[P • VF R]\ASLI A/Z[BFVM U]\R/FGL V\NZGL AFH]V[ HFI K[P U]\R/FGF\ VF\8FGL ;\bIF JWFZJFYL R]\ASLI 1M+GL TLJ|TF JWFZL XSFI K[P • ;M,[GM.0G]\ R]\ASLI 1F[+ ov • HIFZ[ 5}\9FGF\ S[ A[S[,F.8GF\ AMALG 5Z lJ;\JFlCT SZ[, TFZG]\ U]\R/]\ JL\8F/JFDF\ VFJ[ K[P tIFZ[ T[G[ ;M,[GM.0 SC[JFDF\ VFJ[ K[P • ;M,[GM.0GF\ TFZDF\YL JLH5|JFC 5;FZ SZLV[ tIFZ[ AGT]\ R]\ASLI 1M+ VFS'lTDF\ NXF"J[, K[P • T[G]\ 1M+ AFZ D[uG[8GF\ H[J]\ K[P V[8,[ S[ V[S K[0M N5M, VG[ ALHM K[0M S5M, TZLS[ JT"[ K[P 5|JFCGL lNXF p,8FJJFYL 1M+GL lNXF 56 p,8FI K[P V[8,[ S[ N 5M,G[ AN,[S 5M, AG[ K[PVG[ S 5M,G[ AN,[N 5M, AG[ K[P

10. .,[S8=M.g0SXG • SZ\8 JCG SZTF JFCSG[ R]\ASLI 1M+DF\ D}SJFYL TGF 5Z ,FU] 50T]\ A/ ov • HIFZ[ JFCSG[ R]\ASLI 1M+DF\ 1M+G[ ,\A lNXFDF\ D]SLG[ T[DF\YL lJn]T 5;FZ SZJFDF\ VFJ[ K[P tIFZ[ T[GF\ 5Z IF\l+S A/ ,FU[ K[P VF A/G[f YL NXF"JJFDF\ VFJ[ K[P • f=ВІℓ • HIF\ В = O,S; 0[g;L8L ωЬ/m² • І = JFCSDF\YL 5;FZ YTM SZ\8 ( Amp DF\) • ℓ = JFCSGL ,\AF.(metre DF\)\ • VFS'lTDF\ R]\ASLI 1M+G[ ,\A lNXFDF\ ℓ DL8Z ,\AF.GM JFCS D]S[, K[P • 5Z\T] HM JFCS VFS'lTDF\ NXF"jIF 5|DF6[ R]\ASLI A/Z[BFVM ;FY[ θ V\XGM B}6M AGFJ[ TM β GF\ A[ 38SM ,. XSFIP • V[S 38S R]\ASLI A/ Z[BFVMG[ ;DF\TZ K[PH[ βcosθ K[P VF 38SG[ ,LW[ A/ ,FU] 50L XS[ GCL\P • 5Z\T] βsinθ 38S R]\ASLI A/ Z[BFVMG[ ,\A K[P DF8[ ,FU] 50T] A/P • f = В І ℓ • HM θ= 90°CMI TM4 • f = ВІℓ YFIP

11. .,[S8=M.g0SXG • .,[S8=MD[uG[8LS .G0SXG o v • VFS'lTDF\ NXF"jIF D]HA V[S U]\R/FGL ;FY[ U[<J[GMDL8Z HM0LG[ V[S AFZ D[uG[8G[ U]\R/FDF\ h05YL NFB, SZJFDF\ VFJ[ TM U]\R/FDF\ ℮mf 5[NF YFI K[P VG[ U[<J[GMDL8ZGM SF\8M VFJT"G 5FD[ K[P • 5Z\T] H[J\] D[uG[8 U]\R/FDF\ l:YZ Y. HFI K[P T[JM X}gI Y. HFI K[P VG[ U[<J[GMDL8Z X}gI NXF"J[ K[P CJ[ HM D[uG[8G[ h05YL ACFZ SF-JFDF\ VFJ[ TM ℮mf GL lNXF p,8FI K[P VG[ SF\8M lJ~wW lNXFDF\ VFJT"G 5FDLG[ X}gI 5Z VFJ[ K[P HM D[uG[8G[ JWFZ[ h05YL NFB, SZJFDF\ VFJ[ TM VFJT"G JWFZ[ VFJ[ K[P V[8,[ S[ JWFZ[ ℮mf 5[NF YFI K[P • CJ[ HM D[uG[8G[ l:YZ ZFBLG[ U}\R/FG[ B;[0JFDF\ VFJ[ TM 56 p5Z 5|DF6[ H 5ZL6FD VFJ[ K[P VF 5ZYL VF56[ GLR[ D]HAGF\ D]NŸFVM TFZJL XSLV[P • (1)HIF\Z[ U}R/F ;FY[ ;\S/FI[, O,S;DF\ O[ZOFZ YFI K[P tIFZ[ U]\R/FDF\ ℮mf.g0I]; YFI K[P DF8[ U}\R/] l:YZ ZFBLG[ D[uG[8G[ B;[/LV[ VYJF D[uG[8G[ l:YZ ZFBLG[ U]\R/FG[ B;[0LV[ TM 56 ℮mf.g0I]; YFI K[P • (2)HIF\ ;]WL O,S;DF\ O[ZOFZ RF,] CMI tIF\ ;WL H[ ℮mf.g0I]; YFI K[P • (3) HM O[ZOFZGM NZ JWFZ[ CMI TM JWFZ[ ℮mf.g0I]; YFI K[PVFG[ .,[S8=MD[uG[8LS .g0SXG SC[ K[P

12. ℮mf pt5gG YJF DF8[GL XZTM • U}\R/FDF\ ℮mf .g0I]; YJF DF8[ +6 XZTMG]\ 5F,G YJ]\ H~ZL K[P • (1)R]\ASLI 1M+GL CFHZL • (2) JFCSGL CFHZL • (3) R]\ASLI 1M+ VG[ JFCS JrR[ ;F5[1F UlT

13. 0FIG[DLS,L .g0I]:0 ℮mf ov • HIFZ[ SF[., VG[ R]\ASLI O,S; JrR[ ;F5[1F UlT YFI tIFZ[ SM.,DF\ H[ .g0I]; YFI T[G[ 0FIG[DLS,L .g0I]; SC[ K[P • WFZM S[4ℓ DL8Z ,\AF.GM V[S JFCS A,B ωЬ/m²O,S; 0[g;L8LJF/F R\]ASLI 1M+DF\ R\]ASLI 1M+G[ ,\A lNXFDF\V DL8Zq;[Sg0 YL UlT SZ[ K[P • TM U}\R/FDF\ pt5gG YTM ℮mf • ℮ =βℓV YFIP • HM JFCSGL UlT OL<0G[ ,\A lNXFDF\ G CMI VG[ OL<0GL ;FY[ V\XGM B}6M AGFJ[ TM JFCSGL UlTGM O,S;G[ ,\A lNXFGM 38S YFIP DF8[4 • ℮ =βℓVsinθ YFIP • :8[8LS, .g0I]:0 ℮mf ov • VF 5|SFZGF\ ℮mf DF\ O,S;GL S[ SM.,GL EF{lTS UlT YTL GYLP 5Z\T] V[S SM.,GF\ 5|JFCDF\ O[ZOFZ YJFYL T[GF\ 5MTFGFDF\ VYJF ALHL SM.,DF\ ℮mf5|[lZT(include) YFI K[P • :8[8LS,L .g0I];0 ℮mf A[ 5|SFZGF K[P • (i) Self induced e.m.f. (;[<O .g0I]:0 e.m.f.) • (ii) mutually induced e.m.f.(diF}rI]V,L .g0I]:0 e.m.f.)

14. p5;\CFZ • TF,LDFYL"VM D[uG[8GF U]6WDM" ;DHX[P • .,[S8=MD[uG[8MGF lGIDM HF6X[P