Eletromagneti waves He predited eletromagneti wave propagation James Clerk Maxwell (1831-1879)
Eletromagneti waves He predited eletromagneti wave propagation A singular theoretial ahievement of the 19 th entury James Clerk Maxwell (1831-1879)
Eletromagneti waves He predited eletromagneti wave propagation A singular theoretial ahievement of the 19 th entury It was know that time hanging B indued E (araday s law) James Clerk Maxwell (1831-1879)
Eletromagneti waves He predited eletromagneti wave propagation A singular theoretial ahievement of the 19 th entury It was know that time hanging B indued E (araday s law) Another symmetry argument James Clerk Maxwell (1831-1879)
Eletromagneti waves He predited eletromagneti wave propagation A singular theoretial ahievement of the 19 th entury It was know that time hanging B indued E (araday s law) Another symmetry argument Maxwell hypothesized: a time hanging E must indue B James Clerk Maxwell (1831-1879)
Eletromagneti waves He predited eletromagneti wave propagation A singular theoretial ahievement of the 19 th entury It was know that time hanging B indued E (araday s law) Another symmetry argument Maxwell hypothesized: a time hanging E must indue B James Clerk Maxwell (1831-1879) and there was light
Heinrih Hertz (1857-1894) in 1887 generated & deteted eletromagneti (EM) waves in lab
Heinrih Hertz (1857-1894) in 1887 generated & deteted eletromagneti (EM) waves in lab Hertz apparatus
Heinrih Hertz (1857-1894) in 1887 generated & deteted eletromagneti (EM) waves in lab Hertz apparatus L
Heinrih Hertz (1857-1894) in 1887 generated & deteted eletromagneti (EM) waves in lab Hertz apparatus L C
Heinrih Hertz (1857-1894) in 1887 generated & deteted eletromagneti (EM) waves in lab Hertz apparatus L C L* C*
Heinrih Hertz (1857-1894) in 1887 generated & deteted eletromagneti (EM) waves in lab Hertz apparatus L C f 0 100 MHz L* C* f 0 π 1 LC π 1 * L C *
Heinrih Hertz (1857-1894) in 1887 generated & deteted eletromagneti (EM) waves in lab Hertz apparatus EM wave
Heinrih Hertz (1857-1894) in 1887 generated & deteted eletromagneti (EM) waves in lab Hertz apparatus EM wave EM waves are generated beause harges are aelerating
Moving harges produe urrents whih in turn produe B
Moving harges produe urrents whih in turn produe B
Transverse wave E and B at right angles to eah other and both are transverse to wave propagation diretion
Transverse wave E and B at right angles to eah other and both are transverse to wave propagation diretion µ 1 0 ε 0
Transverse wave E and B at right angles to eah other and both are transverse to wave propagation diretion wavelength l µ 1 0 ε 0
Transverse wave E and B at right angles to eah other and both are transverse to wave propagation diretion wavelength l µ 1 0 ε 0 f λ
roperties of eletromagneti waves Speed 3.00 10 8 m/s
roperties of eletromagneti waves Speed 3.00 10 8 m/s Maxwell proved: E B
roperties of eletromagneti waves Speed 3.00 10 8 m/s Maxwell proved: E B EM waves arry energy and linear momentum
roperties of eletromagneti waves Speed 3.00 10 8 m/s Maxwell proved: E B EM waves arry energy and linear momentum Beause E and B fields store energy in them. In fat, energies stored in E & B fields are equal.
Let S intensity average rate at whih EM-wave energy passes through a unit area perpendiular to diretion of wave W/m.
Let S intensity average rate at whih EM-wave energy passes through a unit area perpendiular to diretion of wave W/m. S E B µ max 0 max ( ) E µ max 0 µ 0 ( B ) max
Let S intensity average rate at whih EM-wave energy passes through a unit area perpendiular to diretion of wave W/m. S E B µ max 0 max ( ) E µ max 0 µ 0 ( B ) max Radio station with total power : what is S at distane r from station?
Let S intensity average rate at whih EM-wave energy passes through a unit area perpendiular to diretion of wave W/m. S E B µ max 0 max ( ) E µ max 0 µ 0 ( B ) max Radio station with total power : what is S at distane r from station? S 4πr
Let S intensity average rate at whih EM-wave energy passes through a unit area perpendiular to diretion of wave W/m. S E B µ max 0 max ( ) E µ max 0 µ 0 ( B ) max Radio station with total power : what is S at distane r from station? S 4πr One you know S, you an find E max and B max
Sine the delivers at the surfae of the earth S ~1 kw/m, find E max and B max.
Sine the delivers at the surfae of the earth S ~1 kw/m, find E max and B max. ( ) E S max max µ 0 max 0 µ 0 µ ( E ) S E S
Sine the delivers at the surfae of the earth S ~1 kw/m, find E max and B max. ( ) E S max max µ 0 max 0 µ 0 µ ( E ) S E S
Sine the delivers at the surfae of the earth S ~1 kw/m, find E max and B max. ( ) E S max max µ 0 max 0 µ 0 µ ( E ) S E S
Sine the delivers at the surfae of the earth S ~1 kw/m, find E max and B max. ( ) E S max max µ 0 max 0 µ 0 µ E max 870 V / m ( E ) S E S
Sine the delivers at the surfae of the earth S ~1 kw/m, find E max and B max. ( ) E S max max µ 0 max 0 µ 0 µ ( E ) S E S E max 870 V / m B max E max.9 10 6 T
Deteting EM waves Deteting E-field part E
Deteting EM waves Deteting E-field part E Antenna C L
Deteting EM waves Deteting E-field part E Antenna C L Deteting B-field part B
Deteting EM waves Deteting E-field part E Antenna C L Deteting B-field part Loop antenna B C L
Deteting EM waves Deteting E-field part E Antenna C L Deteting B-field part Loop antenna B C L Indued emf due to hanging B-flux in antenna
Linear momentum arried by EM wave light pressure (N/m )
Linear momentum arried by EM wave light pressure (N/m ) Complete absorption: S
Linear momentum arried by EM wave light pressure (N/m ) m N s m m s m N s m m s J m / s m W / S Complete absorption: S
Linear momentum arried by EM wave light pressure (N/m ) m N s m m s m N s m m s J m / s m W / S Complete absorption: S Complete refletion: S
Linear momentum arried by EM wave light pressure (N/m ) Complete absorption: S S W / m m / s J s m m s N m s m m s N m Complete refletion: S Light bouning off mirror imparts more momentum to mirror
The effet of light pressure on dust in our solar system (Applying hysis 1., p. 67)
The effet of light pressure on dust in our solar system (Applying hysis 1., p. 67) Sun dust partile of radius r and mass m in orbit around R
The effet of light pressure on dust in our solar system (Applying hysis 1., p. 67) Sun dust partile of radius r and mass m in orbit around R light πr 4πR πr S πr 4R r
The effet of light pressure on dust in our solar system (Applying hysis 1., p. 67) Sun R dust partile of radius r and mass m in orbit around light πr 4πR Light not refleted πr S πr 4R r
The effet of light pressure on dust in our solar system (Applying hysis 1., p. 67) Sun R dust partile of radius r and mass m in orbit around light πr 4πR Light not refleted πr S πr 4R r
The effet of light pressure on dust in our solar system (Applying hysis 1., p. 67) Sun R Light output power of dust partile of radius r and mass m in orbit around light πr 4πR Light not refleted πr S πr 4R r
The effet of light pressure on dust in our solar system (Applying hysis 1., p. 67) Sun R Light output power of dust partile of radius r and mass m in orbit around light πr 4πR Light not refleted πr S πr 4R r grav G M R m G M ρ R 4 3 πr 3
The effet of light pressure on dust in our solar system (Applying hysis 1., p. 67) Sun R Light output power of dust partile of radius r and mass m in orbit around light πr 4πR Light not refleted πr S πr 4R r grav G M R m G M ρ R 4 3 πr 3
The effet of light pressure on dust in our solar system (Applying hysis 1., p. 67) Sun R Light output power of dust partile of radius r and mass m in orbit around light πr 4πR Light not refleted πr S πr 4R r grav 4 3 G M ρ πr G M m 3 density of R R dust partile
Compute light / grav ratio
Compute light / grav ratio light 4R r grav G M ρ R 4 3 πr 3
4R r light 3 grav R r 3 4 M G π ρ ρ π ρπ r 1 16 GM 3 3R r 4 GM 4R r 3 grav light Compute light / grav ratio
4R r light 3 grav R r 3 4 M G π ρ ρ π ρπ r 1 16 GM 3 3R r 4 GM 4R r 3 grav light Compute light / grav ratio
4R r light 3 grav R r 3 4 M G π ρ ρ π ρπ r 1 16 GM 3 3R r 4 GM 4R r 3 grav light Compute light / grav ratio
4R r light 3 grav R r 3 4 M G π ρ ρ π ρπ r 1 16 GM 3 3R r 4 GM 4R r 3 grav light 11 6 30 kg m N 10 6.8 G W; 10 3.7 kg; 10.0 M Compute light / grav ratio
4R r light 3 grav R r 3 4 M G π ρ ρ π ρπ r 1 16 GM 3 3R r 4 GM 4R r 3 grav light 11 6 30 kg m N 10 6.8 G W; 10 3.7 kg; 10.0 M 3 kg/m 3 10 3 g/ 3 ρ or dust partile Compute light / grav ratio
4R r light 3 grav R r 3 4 M G π ρ ρ π ρπ r 1 16 GM 3 3R r 4 GM 4R r 3 grav light 11 6 30 kg m N 10 6.8 G W; 10 3.7 kg; 10.0 M µ µ m) r( m 0.18 grav light Compute light / grav ratio 3 kg/m 3 10 3 g/ 3 ρ or dust partile
Compute light / grav ratio light 4R r grav G M ρ R 4 3 πr 3 light grav GM r 4R 4ρπr 3 3R 3 GM 16πρ 1 r M.0 10 30 or dust partile kg; 3.7 10 6 W; G 6.8 10 ρ 3 g/ 3 10 3 kg/m 3 11 N m kg light grav 0.18 µ m r( µ m) or r < 0.18 mm, dust partile will pushed out of solar system!