Ampere’s law and applications to wires and solenoids - Question Bank
1. Ampere's law is particularly useful when dealing with conductors carrying current that exhibit:
2. In a solenoid, the magnetic field lines are most densely packed:
3. Which of the following statements about Ampere's law is FALSE?
4. The magnetic field strength inside a solenoid is directly proportional to:
5. A long straight wire carries a current I. If a cylindrical surface of radius r is chosen as the Amperian loop, coaxial with the wire, the integral ∮ B ⋅ dl is:
6. If the permeability of the medium inside a solenoid is μ instead of μ₀, the magnetic field inside becomes:
7. What is the magnetic flux through the surface enclosed by an Amperian loop if no net current passes through the loop?
8. The magnetic field at a point inside a long solenoid depends on:
9. Ampere's law is particularly useful for calculating magnetic fields in situations with:
10. The magnetic field lines inside a solenoid are:
11. For a hollow cylindrical conductor of inner radius r₁ and outer radius r₂ carrying a uniform current I, what is the magnetic field at a distance r such that r₁ < r < r₂?
12. Consider a long straight wire carrying current I. The magnetic field at a distance r is B. If the wire is hollow with inner radius r₁ and outer radius r₂, and the current flows uniformly through the cross-section, what is the field at r < r₁?
13. What is the magnetic field at the center of a circular loop of radius R carrying current I, if the loop is made of wire with cross-sectional area A?
14. A current loop creates a magnetic field. If the current is doubled, the magnetic field at any point will:
15. Ampere's law is a macroscopic law, while Biot-Savart law is a microscopic law. Ampere's law can be derived from Biot-Savart law under conditions of:
16. If the current in a solenoid is reversed, the direction of the magnetic field inside the solenoid:
17. The magnetic field inside a toroid is:
18. What is the magnetic field at a distance r from the axis of a long solenoid, outside the solenoid?
19. Ampere's law is valid for:
20. The magnetic field of a long straight wire is proportional to:
21. If two long straight wires carry currents in opposite directions, the magnetic field at a point midway between them is:
22. Consider two long straight wires placed parallel to each other, separated by a distance d, and carrying currents I₁ and I₂ in the same direction. The magnetic field at a point exactly midway between them is:
23. What is the magnetic field at a point inside a long solenoid far from the ends, if the solenoid is carrying a current I and has n turns per unit length?
24. A thin wire carries a current I. If the wire is bent into a circular loop of radius R, the magnetic field at the center is B_center. If it is bent into a square loop of side length L, the magnetic field at the center is B_square. Which statement is true?
25. For a current distribution with cylindrical symmetry, the magnetic field depends on:
26. If we consider an Amperian loop that encloses no net current, then the line integral of B around that loop is:
27. Ampere's law is applicable to which type of currents?
28. The magnetic field outside an ideal toroid is:
29. The magnetic field inside a toroid is strongest where the windings are:
30. A toroid is a solenoid bent into a circular shape. For a toroid with N turns and carrying current I, the magnetic field inside the toroid at a radius r is:
31. The unit of magnetic field (B) is Tesla (T). Which of the following is equivalent to Tesla?
32. Ampere's law is a consequence of:
33. What happens to the magnetic field inside a solenoid if the current (I) is increased, while keeping the number of turns per unit length (n) constant?
34. What happens to the magnetic field inside a solenoid if the number of turns per unit length (n) is increased, while keeping the current (I) constant?
35. If a solenoid is not long and ideal, the magnetic field:
36. To apply Ampere's law to a solenoid, we choose an Amperian loop that is:
37. Consider a circular loop of radius R carrying current I. The magnetic field at the center of the loop is:
38. If the distance from a long straight wire carrying current I is doubled, the magnetic field at that point will:
39. If the current in a long straight wire is doubled, the magnetic field at a given distance from the wire will:
40. The magnetic field outside an ideal, long solenoid is approximately:
41. What is the magnitude of the magnetic field inside a long solenoid carrying current I, with n turns per unit length?
42. A solenoid is a coil of wire wound into a tightly packed helix. For an ideal, long solenoid, the magnetic field inside is approximately:
43. To determine the direction of the magnetic field around a straight current-carrying wire, one can use:
44. The magnetic field lines around a long straight current-carrying wire are:
45. Consider a long straight wire carrying a current I. What is the magnitude of the magnetic field at a perpendicular distance r from the wire?
46. Ampere's law is most useful for calculating the magnetic field when the symmetry of the problem allows for:
47. In Ampere's law, ∮ B ⋅ dl = μ₀I_enc, what does 'I_enc' represent?
48. In Ampere's law, ∮ B ⋅ dl = μ₀I_enc, what does 'μ₀' represent?
49. Ampere's law relates the magnetic field around a closed loop to the electric current passing through the loop. Mathematically, it is stated as: