Question

1. In Ampere’s law, when we integrate the magnetic field along a loop, which are summing?

   a. the field components that are parallel to the path elements, at every point along the loop
   b. the field components that are perpendicular to the path elements, at every point along the loop
   c. the magnitudes of the field vectors at every point along the loop

2. Which describes the magnetic field at a point inside a long wire that carries current uniformly across its circular cross-sectional area?

   a. The field is directed radially inward.
   b. The field is tangent to a circle through the point and concentric with the wire.
   c. The field is directed radially outward.

3. Which is true about a solenoid?

   a. The internal magnetic field is approximately uniform. The external magnetic field is weak.
   b. The magnetic field is approximately uniform both inside and outside the solenoid.
   c. The internal magnetic field is weak. The external magnetic field is approximately uniform.

4. In using Ampere’s law for a solenoid as in this section, which is true about the values of the integration parts?

   a. The integrations parallel to the length of the solenoid give a zero result; those perpendicular to the length give a nonzero result.
   b. The integrations parallel to the length of the solenoid give a nonzero result; those perpendicular to the length give a zero result.
   c. The integrations parallel and perpendicular to the length of the solenoid give a zero result.
   d. The integrations parallel and perpendicular to the length of the solenoid give a nonzero result.

5. Which describes the magnetic field along the central axis of a current loop?

   a. The field is directed along the axis and away from the loop on one side and toward the loop on the other side.
   b. The field is directed along the axis and toward the loop on both sides of the loop.
   c. The field is directed along the axis and away from the loop on both sides of the loop.
   d. The field is perpendicular to the axis.

Answer 1

1. magnetic field Bparall *dL = uo I

so

a. the field components that are parallel to the path elements, at every point along the loop

is correct

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2. For Circular motion of Current

magnetic field will be b. The field is tangent to a circle through the point and concentric with the wire.

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3. magneic field Due to solonoid is B = uo n i

field wil be inside the Solonoid

so answer is

a. The internal magnetic field is approximately uniform. The external magnetic field is weak.

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4. b. The integrations parallel to the length of the solenoid give a nonzero result; those perpendicular to the length give a zero result.

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5.

c. The field is directed along the axis and away from the loop on both sides of the loop.