Electromagnetics Field (3140912) MCQs

MCQs of Steady Magnetic Fields

Showing 1 to 10 out of 43 Questions
1.
An element dl =dx, (where dx = 1 cm) is placed at the origin and carries a large current I = 10 A. What is the magnetic field on the Y-axis at a distance of 0.5 meter ?
(a) 2×10–8 T
(b) 4×10–8 T
(c) –2×10–8 T
(d) –4×10–8 T
Answer:

Option (b)

2.
A length L of wire carries a steady current 1 A. It is bent first to form a coil of 1 turn. The same length is now bent more sharply to give a double loop of smaller radius. The magnetic field at the center caused by the same current is
(a) One forth of its first value
(b) Same as of its first value
(c) Four times of its first value
(d) Half of its first value
Answer:

Option (c)

3.
If a long hollow copper pipe carries a direct current, the magnetic field associated with the current will be
(a) Inside the pipe only
(b) Outside the pipe only
(c) Neither inside nor outside the pipe
(d) Both inside and outside the pipe
Answer:

Option (b)

4.
The magnetic induction at a point P which is at a distance 4 cm from a long current carrying wire is 10–8 T. The field of induction at a distance 12 cm from the same current will be
(a) 3.33×10–9 T
(b) 1.11×10–4 T
(c) 3×10–3 T
(d) 9×10–2 T
Answer:

Option (a)

5.
The strength of the magnetic field at a point y near a long straight current carrying wire is B. The field at a distance y/2 will be
(a) B/2
(b) B/4
(c) 2B
(d) 4B
Answer:

Option (c)

6.
The magnetic field (B) at the center of a circular coil of radius a, through which a current I flows is
(a) B ∝ a
(b) B ∝ a2
(c) B ∝ I
(d) B ∝ I2
Answer:

Option (c)

7.
What is incremental field strength at P2 due to the current element of 2πāz μAm at P1? The coordinates of P1 and P2 are (4,0,0) and (0,3,0) respectively.
(a) 12āx+16āy nA/m
(b) −12āx+16āy nA/m
(c) −12āx−16āy nA/m
(d) 12āx−16āy nA/m
Answer:

Option (c)

8.
What will be the ΔH2 for the value, P1(0, 0, 2), P1(4, 2, 0), I1ΔL1 = 2πāz μAm?
(a) −8.5āx+17āy nA/m
(b) −8.5āx+17āy A/m
(c) −8.5āx−17āy A/m
(d) +8.5āx+17āy nA/m
Answer:

Option (a)

9.
Biot Savart's law in magnetic field is analogous to which law in electric field?
(a) Gauss law
(b) Faraday's law
(c) Coulomb’s law
(d) Ampere's law
Answer:

Option (c)

10.
Which of the following cannot be computed using the Biot Savart's law?
(a) Magnetic field intensity
(b) Magnetic flux density
(c) Electric field intensity
(d) Permeability
Answer:

Option (c)

Showing 1 to 10 out of 43 Questions