what are the conditions for applying ampere circuital law?

Vikas TU
14149 Points
8 years ago
• Ampere's circuital law in magnetism is analogous to gauss's law in electrostatics
• This law is also used to calculate the magnetic field due to any given current distribution
• This law states that
" The line integral of resultant magnetic field along a closed plane curve is equal to μ0 time the total current crossing the area bounded by the closed curve provided the electric field inside the loop remains constant" Thus:
• (Integeral Integeration) B.dl = uI

Vikas TU
14149 Points
8 years ago
Some points get remained:

• The integeral integeation above equation  means that scalar product B.dl is to be integrated around the closed loop known as Amperian loop whose beginning and end point are same
• Anticlockwise direction of integration as chosen in figure 9 is an arbitrary one we can also use clockwise direction of integration for our calculation depending on our convenience
• To apply the ampere's law we divide the loop into infinitesimal segments dl and for each segment, we then calculate the scalar product of B and dl
• B in general varies from point to point so we must use B at each location of dl
• Amperion Loop is usually an imaginary loop or curve ,which is constructed to permit the application of ampere's law to a specific situation.

jyoti bhatia
202 Points
8 years ago
Follow the steps given to apply Ampere’s circuital law:
Step 1: Consider a symmetrical closed path such that it encloses direct current I once. This is Amperian path.
Step 2: Consider differential length dL depending on co-ordinate system used.
Step 3: Identify the symmetry and find in which direction H exists accoridng to co-ordinate system used.
Step 4: Find H*dL, the dot product. dL and H should be in same direction.
Step 5: Find integral of H*dL.around the closed path assumed. Equate it to current I enclosed by the path.
Soving this for H, we get required magnetic field intensity due to direct currnet I.
To apply Ampere’s circuital law, following conditions must be satisfied:
1. The H is either tangential or normal to the path, at each point of the closed path.
1. The magnitude of H must be same at all points of the path wher H is tangential. Thus, identifying symmetry and identifying components of H present, plays an important role while applying Ampere’s circuital law.