Ampere Maxwell's equation

MImtiazKhan2 234 views 12 slides Sep 19, 2021
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About This Presentation

Ampere-Maxwell’s Law: Maxwell correction to Ampere’s Law
Maxwell said that there has to be some current existing between plates. There are no conduction electrons between plates BUT there is time-varying E between plates, which generates a current. The E is directed from +ve plate to –ve plate...


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4. Ampere-Maxwell’s Law Ampere’s Law ‘ The line integral of the magnetic field B around any closed loop is times the net steady current I enclosed by this path ”   Maxwell’s Equations (1) dl I p B B . dl = B dl cos 0= B dl As, B is uniform at each point on the field line: B . dl = B (2 π r) (2) Equating (1) and (2): B =   i.e. the magnetic field a distance r from a long straight wire carrying a steady current I. https://www.youtube.com/channel/UC1hrAjhSKGAsWZ7LvR_rbRg Here is a link of Youtube video. You can watch this lecture on Youtube , as well.

4. Ampere-Maxwell’s Law Ampere’s Law ‘ The line integral of the magnetic field B around any closed loop is times the net steady current I enclosed by this path ”   Maxwell’s Equations (1) dl I p B B . dl = B dl cos 0= B dl As, B is uniform at each point on the field line: B . dl = B (2 π r) (2) Equating (1) and (2): B =   i.e. the magnetic field a distance r from a long straight wire carrying a steady current I. Ampere’s law is true for steady currents T he Magnetic field inside the loop remains constant I , arising due to flow of charges, is called the ’ conduction current’ I C c

4. Ampere and Maxwell’s Law Ampere’s Law ‘ The line integral of the magnetic field B around any closed loop is times the net steady current I enclosed by this path ”   Maxwell’s Equations (1) dl I p B B . dl = B dl cos 0= B dl As, B is uniform at each point on the field line: B . dl = B (2 π r) (2) Equating (1) and (2): B =   i.e. the magnetic field a distance r from a long straight wire carrying a steady current I. Ampere’s law is true for steady currents T he Magnetic field inside the loop remains constant I , arising due to flow of charges, is called the ’ conduction current’ I C c Let’s there is a capacitor and the Amperian surface is like a bag and its top is open : L A Ampere’s Law

4. Ampere and Maxwell’s Law Ampere’s Law ‘ The line integral of the magnetic field B around any closed loop is times the net steady current I enclosed by this path ”   Maxwell’s Equations (1) dl I p B B . dl = B dl cos 0= B dl As, B is uniform at each point on the field line: B . dl = B (2 π r) (2) Equating (1) and (2): B =   i.e. the magnetic field a distance r from a long straight wire carrying a steady current I. Ampere’s law is true for steady currents T he Magnetic field inside the loop remains constant I , arising due to flow of charges, is called the ’ conduction current’ I C c Let’s there is a capacitor and the Amperian surface is like a bag and its top is open : + + + + + - - - - - - - - - - + + + + + L A Ampere’s Law

4. Ampere and Maxwell’s Law Ampere’s Law ‘ The line integral of the magnetic field B around any closed loop is times the net steady current I enclosed by this path ”   Maxwell’s Equations (1) dl I p B B . dl = B dl cos 0= B dl As, B is uniform at each point on the field line: B . dl = B (2 π r) (2) Equating (1) and (2): B =   i.e. the magnetic field a distance r from a long straight wire carrying a steady current I. Ampere’s law is true for steady currents T he Magnetic field inside the loop remains constant I , arising due to flow of charges, is called the ’ conduction current’ I C c Let’s there is a capacitor and the Amperian surface is like a bag and its top is open : + + + + + - - - - - - - - - - + + + + + L A Ampere’s Law

4. Ampere and Maxwell’s Law Ampere’s Law ‘ The line integral of the magnetic field B around any closed loop is times the net steady current I enclosed by this path ”   Maxwell’s Equations (1) dl I p B B . dl = B dl cos 0= B dl As, B is uniform at each point on the field line: B . dl = B (2 π r) (2) Equating (1) and (2): B =   i.e. the magnetic field a distance r from a long straight wire carrying a steady current I. Ampere’s law is true for steady currents T he Magnetic field inside the loop remains constant I , arising due to flow of charges, is called the ’ conduction current’ I C c Let’s there is a capacitor and the Amperian surface is like a bag and its top is open : + + + + + - - - - - - - - - - + + + + + As there is no current flowing inside the capacitor, hence B . dl = 0. At the same point ‘P’ but with different A mperian surfaces, the B is not same. Conc : There are some gaps in the Ampere’s law. Maxwell corrected and made Ampere’s law consistent in all cases . What happens between the plates while the current  I  is flowing? L A Ampere’s Law

Maxwell’s Equations + + + + + - - - - - - - - - - + + + + + E Maxwell correction to Ampere’s Law There has to be some I existing between plates. There are no conduction electrons between plates BUT There is time-varying E between plates, which generates I . The E is directed from + ve plate to – ve plate, because the amount of charge on capacitor increases with time, AND The E between plates increases with time, as well. He called this new current as a displacement current, I d   .

Maxwell’s Equations As the amount of charge on the capacitor increases with time, hence the q charge, changes with time, produces a current: I d    = dq /dt + + + + + - - - - - - - - - - + + + + + E For a capacitor, , and Maxwell correction to Ampere’s Law There has to be some I existing between plates. There are no conduction electrons between plates BUT There is time-varying E between plates, which generates I . The E is directed from + ve plate to – ve plate, because the amount of charge on capacitor increases with time, AND The E between plates increases with time, as well. He called this new current as a displacement current, I d   . Φ E d i.e. Current is produced because of changing electric flux w.r.t time OR Electric flux is generated due to the presence of E between plates.

Maxwell’s Equations As the amount of charge on the capacitor increases with time, hence the q charge, changes with time, produces a current: I d    = dq /dt + + + + + - - - - - - - - - - + + + + + E For a capacitor, , and Maxwell correction to Ampere’s Law There has to be some I existing between plates. There are no conduction electrons between plates BUT There is time-varying E between plates, which generates I . The E is directed from + ve plate to – ve plate, because the amount of charge on capacitor increases with time, AND The E between plates increases with time, as well. He called this new current as a displacement current, I d   . Φ E d i.e. Current is produced because of changing electric flux w.r.t time OR Electric flux is generated due to the presence of E between plates. CONC: Cur rent is not ZERO between plates but it is I d   AND B is produced by the time varying E or I d  

Maxwell’s Equations As the amount of charge on the capacitor increases with time, hence the q charge, changes with time, produces a current: I d    = dq /dt + + + + + - - - - - - - - - - + + + + + E For a capacitor, , and Maxwell correction to Ampere’s Law There has to be some I existing between plates. There are no conduction electrons between plates BUT There is time-varying E between plates, which generates I . The E is directed from + ve plate to – ve plate, because the amount of charge on capacitor increases with time, AND The E between plates increases with time, as well. He called this new current as a displacement current, I d   . Φ E d Conc : B s are produced both by a conduction current and by a time-varying field. A changing electric field induces a magnetic field Maxwell correction to Ampere’s Law is: c c i.e. Current is produced because of changing electric flux w.r.t time OR Electric flux is generated due to the presence of E between plates CONC: Cur rent is not ZERO between plates but it is I d   AND B is produced by the time varying E or I d  

Maxwell’s Equations As the amount of charge on the capacitor increases with time, hence the q charge, changes with time, produces a current: I d    = dq /dt + + + + + - - - - - - - - - - + + + + + E For a capacitor, , and Maxwell correction to Ampere’s Law There has to be some I existing between plates. There are no conduction electrons between plates BUT There is time-varying E between plates, which generates I . The E is directed from + ve plate to – ve plate, because the amount of charge on capacitor increases with time, AND The E between plates increases with time, as well. He called this new current as a displacement current, I d   . Φ E d Conc : B s are produced both by a conduction current and by a time-varying field. A changing electric field induces a magnetic field Maxwell correction to Ampere’s Law is: c c i.e. Current is produced because of changing electric flux w.r.t time OR Electric flux is generated due to the presence of E between plates CONC: Cur rent is not ZERO between plates but it is I d   AND B is produced by the time varying E or I d