Elect Magnet 1

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<p>11 1 1 www.zaluu.comwww.zaluu.com 22 ((3 . 3 .)) 32 32 48 48 48 48 : 100 : 100 , 10 , 10 20 20 30 30 40 40 www.zaluu.comwww.zaluu.com 33 1. . . . . . . . . . . . . 4 1. . . . . . . . . . . . . 4 (6) (6) 2. . . . . . . . . . . . . . 2 2. . . . . . . . . . . . . . 2 (3) (3) 3. . . . . . . . . 4 3. . . . . . . . . 4 (6) (6) 4. . . . . . 4. . . . . . 2 2 (3) (3) 5. 5. . . . . . . . . . 2 . . . . . . . . . 2 (3) (3) 6. 6. . . . . . . 2 . . . . . . 2 (3) (3) 7. . . . . . . . . . . . . . 3 7. . . . . . . . . . . . . . 3 (3) (3) 8. 8. . . 3 . . 3 (6) (6) 9. . . . . . . . . . . . . 4 9. . . . . . . . . . . . . 4 (6) (6) 10. . . . . . . . . . . . . . . . 2 10. . . . . . . . . . . . . . . . 2 (3) (3) 11. . . . . . 2 11. . . . . . 2 (3) (3) 12. 12. . . . . . 2 . . . . . 2 (3) (3)32 32 (48) (48)www.zaluu.comwww.zaluu.com 44, , R.A.Serway. PHISICS: For Scientists and R.A.Serway. PHISICS: For Scientists and Engineers Engineers .. . . 1970 .. . . 1970 ... . 2 ... . 2 .. . .. . . . . . . . . .. . . . . .. . www.zaluu.comwww.zaluu.com 55 : : 800 800-- 1600 . 1600 . (Gilbert) (Gilbert) 1785 . 1785 . (Coulomb) (Coulomb)-- : : 1/r 1/r22 1820 . 1820 . (Oersted) (Oersted): : 1831 . 1831 . (Faraday) (Faraday)-- 1864 . 1864 . (Maxwell) (Maxwell) 1887 . 1887 . (Hertz) (Hertz)-- 1895 . , . 1895 . , . , , www.zaluu.comwww.zaluu.com 661. 1. 1.1. 1.1. 1.2. . 1.2. . 1.3. 1.3. 1.4. 1.4. 1.5. 1.5. 1.6. 1.6. 1.7. 1.7. 1.8. 1.8. www.zaluu.comwww.zaluu.com 771.1. 1.1. , , , , : : www.zaluu.comwww.zaluu.com 88 , , 2 2 , , . . 1909 : 1909 : q=Ne, N=1,2,3, q=Ne, N=1,2,3, -- F~1/r F~1/r2219e 1,60207 10= www.zaluu.comwww.zaluu.com 99 ((200 200 ) ) , , : : 2 1e , e3 3+ 19e 1,60207 10= www.zaluu.comwww.zaluu.com 10 10 ?? 2 2 1 1 , , 1 1 ~~2000 2000 ? ? = 19 6 23 226q 1,6 10 10 6 10 4,46 1056 (= ( = 2 2 9F ( 4,46 10 ) 9 10= = 71,8 10 18www.zaluu.comwww.zaluu.com 11 11 1.2. . 1.2. . 3 3 : : . , . , , ... , ... : : . , . , , , ... ... : : . . Ge, Si Ge, Si . . . . . . www.zaluu.comwww.zaluu.com 12 12 )) ) ) ) ) , , )) ? ?+ + +++++ ++---- ---- -- - --+ +++++++-------+ +++++++- - - -----------+ +++++++- - - ++ +++++++ +++++++++++www.zaluu.comwww.zaluu.com 13 131.3. 1.3. Coulomb`s law Coulomb`s law 1785 . 1785 . 2 2 2 2 2 2 2 2 , , , , -- 1 22q qF kr= 9 2 2k 8,9875 10 / = 01k4tc= 12 2 20 8,8542 10 /( ) c = www.zaluu.comwww.zaluu.com 14 14 oo ? ? : 2 : 2-- 1772 ? : 1772 ? : 100 : 100 : 1971 : 1971 : 10 1077 10 10--17 17 ? ? 1 1 , ? , ? 66,3 ,310 1018 18 , , 1 1 33Cu Cu 10 1023 23 21Fr o 0,02 o s55 10 o s 162,7 3,1 10 o s www.zaluu.comwww.zaluu.com 15 15 2 2 22-- 1 212 2q qF k rr= 12 21F F = 1 12 13 14F F F F ... = + + + -++q1+q2F12F21q1q2F12F21www.zaluu.comwww.zaluu.com 16 16 20.1 20.1 3 3 . . qq11=q =q33=5 =5 , , qq22==--2 2 a=0,1 a=0,1 . . qq33 . . qq11 qq22 F31+ -+ q1q2 q3xyaa2aF32F33 131 2q qF k( 2a )= =32F =2 6 692 2 ( 5 10 )( 5 10 )( 9 10 ) 11 2( 0,1 ) =2 6 693 22 2 2q q ( 5 10 )( 2 10 )k ( 9 10 ) 9 a ( 0,1 ) = =www.zaluu.comwww.zaluu.com 17 17 qq33 xx 98 9800 FF31 31 xx 45 4500. . xx yy FF31x 31x=F =F31y 31y= F = F31 31cos45 cos4500=7,9 =7,9 . . FF32 32 xx-- . . FF33 FFxx=F =F31x 31x+F +F32 32=7,9 =7,9 --9,0 9,0 = = --1,1 1,1 FFyy=F =F31y 31y=7,9 =7,9 F31+ -+ q1q2 q3xyaa2aF32F33F ( 1,1i 7,9 j ) = + 2 2( 1,1) (7,9 ) 8,0 + =F31xF31yFxFywww.zaluu.comwww.zaluu.com 18 18 20. 20.22 : : qq33 ? ? qq33-- FF31 31, F , F32 32 , , qq11=15 =15 x=2 x=2 , , qq22=6 =6 . . qq33 xx ? ?++yx2 q1q2_q3x 2-xF31F323 131 2q qF k ;( 2 x )= 2 332 2q qF kx=3 1 3 22 2q q q qk k( 2 x ) x= 2 22 1( 2 x ) q x q =2 6 2 6( 4 4x x )( 6 10 ) x ( 15 10 ) + = x=0,775 ?www.zaluu.comwww.zaluu.com 19 19 20.3 20.3 The electron and proton The electron and proton of a hydrogen atom are of a hydrogen atom are separated (on the separated (on the average) by a distance average) by a distance of about 5.3 of about 5.310 10--11 11 m. m. Find the magnitude of Find the magnitude of the electrical force and the electrical force and the gravitational force the gravitational force between the two between the two particles. particles. 5.3 5.310 10--11 11 . . .Solution: From Coulombs law, we find that the attractive electrical force has the magnitude: 2 2 19 29 8e 2 2 11 2e ( 1,6 10 )F k 9,0 10 8,2 10 r ( 5,3 10 ) = = = www.zaluu.comwww.zaluu.com 20 20 Using Newtons universal law of gravity and Table Using Newtons universal law of gravity and Table 20.1, we find that the gravitational force is equal to 20.1, we find that the gravitational force is equal to 20.1 20.1-- 2 31 27e p 11 47g 2 2 11 2m m ( 9,11 10 )( 1,67 10 )F G ( 6,67 10 ) 3,6 10 r ( 5,3 10 ) = = = The ratio Fe/Fg ~~3310 1039 39. . Thus the gravitational force Thus the gravitational force between charged atomic particles is negligible between charged atomic particles is negligible compared with the electrical force. compared with the electrical force. Fe/Fg~~3310 1039 39.. .www.zaluu.comwww.zaluu.com 21 211.4. 1.4. The electric field The electric field : : : : : : EE-- , , // // EE-- FF-- qq00-- EE qq0 0 0g F / m = 0E F / q = www.zaluu.comwww.zaluu.com 22 22 . . 0q 00FE limq= q&gt;&gt;q0++ ++ ++++qC BAq0F++ ++ ++++qA0q q'~+ +++q' F'www.zaluu.comwww.zaluu.com 23 23 qq00 rr qq -- . . EE qq00 03qqF k rr= r0FEq= 3qE k rr= 2qE k rr=www.zaluu.comwww.zaluu.com 24 24 ++qPq0 Er r qPq0E r+q1q23qE k rr= P E1E2E1 2E E E = + ii3i iqE k rr= iE E = www.zaluu.comwww.zaluu.com 25 25 20.5 20.5 qq11=7 =7 , , qq22== --5 5 xx 0,3 0,3 . . a) a) (0;0,4) (0;0,4) PP . . ) ) PP 2210 10--8 8 . . qq11 EE11 qq22 EE22 xy+ + q1 q2P0,3 0,4 0,5 E1E22 6911 2 2 21q 7 10 E k ( 9 10 )r ( 0,4) = = =53,9 10 / = 2 6922 2 2 22q 5 10 E k ( 9 10 )r ( 0,5) = = =51,8 10 / = uwww.zaluu.comwww.zaluu.com 26 26 EE1 1 yy EE22 x, x, yy PP EE11, E , E22 E=2,7 E=2,710 1055// ||=66 =66 ) ) 2x 2E E cosu = =2 yE =E2xE2yxy+ q1 q2PE1E2uu51E 3,9 10 j / = 5 52E ( 1,1 10 i 1,4 10 j ) / = E|1 2E E E = + = 8 5 5 3 30F q E ( 2 10 )( 1,1 10 i 2,5 10 j ) ( 2,2 10 i 5 10 j ) = = + = + 5 5( 1,1 10 i 2,5 10 j ) / + 532 5 E 1,1 10 / = 2E sinu = 542 5 E 1,4 10 / = www.zaluu.comwww.zaluu.com 27 27 20.6 20.6 Electric field of a dipole: Electric field of a dipole: An An electric dipole electric dipoleconsists of a positive consists of a positive charge charge qq and a negative and a negative charge charge qq separated by separated by a distance a distance 2a 2a, as in Fig. , as in Fig. Find the electric field Find the electric field EEdue to these charges due to these charges along the along the yy axis at the axis at the point point PP, which is a , which is a distance distance yy from the from the origin. Assume that origin. Assume that y&gt;&gt;a y&gt;&gt;a. . . . 2 q q . E y y P . y&gt;&gt;a y&gt;&gt;a . .www.zaluu.comwww.zaluu.com 28 28 y&gt;&gt;a y&gt;&gt;a HCl HCl 2 2 EE11, E , E22 PP E=E E=E11+E +E22 EE11, E , E22 yy xx E=2E E=2Exx=2E =2E11cos cosuu xx-- + xyPq -qa ay r ru u1 2 2qE E kr= = =E1E2Euu122 2cos a / r a /( y a ) u = = +1E 2E cosu = =32qaE ky~2 2qky a +1 2 2 2 2 2q a2k( y a ) ( y a ) =+ + 32 2 22qak( y a ) +www.zaluu.comwww.zaluu.com 29 29 1. 1. 2. 2. . . ? ? 3. 3. . . . . . . 4. 4. . . . . ? ? ? ?www.zaluu.comwww.zaluu.com 30 30 5. 5. ? . ? . 6. 6. ? ? . . 7. , 7. , ? ? . . 8. 8. aa , , r&gt;2a r&gt;2a . . ? . ? . 9. 9. ? ? 10. 10. . . . . . .www.zaluu.comwww.zaluu.com</p>