Magnetic Fields, Induction and Magnetic Circuits - Electromagnetic Fields - Electrical Engineering Previous Year Questions

1

2007 · Electrical Engineering · Electromagnetic Fields · Magnetic Fields, Induction and Magnetic Circuits

Electrical Engineering (EE) 2007

The average force on the core to reduce the air gap will be

A

832.29 N

B

1666.22 N

C

3332.47 N

D

6664.84 N

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2

2008 · Electrical Engineering · Electromagnetic Fields · Magnetic Fields, Induction and Magnetic Circuits

Electrical Engineering (EE) 2008

A coil of 300 turns is wound on a non-magnetic core having a mean circumference of 300 mm and a cross-sectional area of 300 mm². The inductance of the coil corresponding to a magnetizing current of 3A will be (Given that μ0 = 4π x 10⁻⁷ H/m)

A

37.68 μH

B

113.04 μH

C

37.68 mH

D

113.04 mH

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3

2013 · Electrical Engineering · Electromagnetic Fields · Magnetic Fields, Induction and Magnetic Circuits

Electrical Engineering (EE) 2013 [Session 1]

The flux density at a point in space is given by B = 4x aₓ + 2ky aᵧ + 8a_z Wb/m². The value of constant k must be equal to

A

-2

B

-0.5

C

+0.5

D

+2

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4

2013 · Electrical Engineering · Electromagnetic Fields · Magnetic Fields, Induction and Magnetic Circuits

Electrical Engineering (EE) 2013 [Session 1]

Given a vector field \( \mathbf{F} = y^2 x \mathbf{a}_x - yz \mathbf{a}_y - x^2 \mathbf{a}_z \), the line integral \( \int \mathbf{F} \cdot d\mathbf{l} \) evaluated along a segment on the x-axis from \( x = 1 \) to \( x = 2 \) is

A

-2.33

B

0

C

2.33

D

7

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5

2013 · Electrical Engineering · Electromagnetic Fields · Magnetic Fields, Induction and Magnetic Circuits

Electrical Engineering (EE) 2013 [Session 2]

The flux density at a point in space is given by \(\mathbf{B}=4x\mathbf{a}_x+2ky\mathbf{a}_y+8\mathbf{a}_z\ \text{Wb/m}^2\). The value of constant \(k\) must be equal to

A

\(-2\)

B

\(-0.5\)

C

\(+0.5\)

D

\(+2\)

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6

2013 · Electrical Engineering · Electromagnetic Fields · Magnetic Fields, Induction and Magnetic Circuits

Electrical Engineering (EE) 2013 [Session 3]

The flux density at a point in space is given by \( \mathbf{B} = 4x\mathbf{a}_x + 2ky\mathbf{a}_y + 8\mathbf{a}_z \text{ Wb/m}^2 \). The value of constant \( k \) must be equal to

A

-2

B

-0.5

C

+0.5

D

+2

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7

2013 · Electrical Engineering · Electromagnetic Fields · Magnetic Fields, Induction and Magnetic Circuits

Electrical Engineering (EE) 2013 [Session 3]

Given a vector field \[\mathbf{F} = y^2 x \mathbf{a}_x - y z \mathbf{a}_y - x^2 \mathbf{a}_z,\] the line integral \[\int \mathbf{F} \cdot d\mathbf{l}\] evaluated along a segment on the x-axis from \(x = 1\) to \(x = 2\) is

A

-2.33

B

0

C

2.33

D

7

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8

2013 · Electrical Engineering · Electromagnetic Fields · Magnetic Fields, Induction and Magnetic Circuits

Electrical Engineering (EE) 2013 [Session 4]

The flux density at a point in space is given by \(\mathbf{B} = 4x\mathbf{a}_x + 2ky\mathbf{a}_y + 8\mathbf{a}_z \text{ Wb/m}^2\). The value of constant k must be equal to

A

-2

B

-0.5

C

0.5

D

+2

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9

2014 · Electrical Engineering · Electromagnetic Fields · Magnetic Fields, Induction and Magnetic Circuits

Electrical Engineering (EE) 2014 [Session 1]

The following four vector fields are given in Cartesian co-ordinate system. The vector field which does not satisfy the property of magnetic flux density is

A

\(y^2\hat{a}_x + z^2\hat{a}_y + x^2\hat{a}_z\)

B

\(z^2\hat{a}_x + x^2\hat{a}_y + y^2\hat{a}_z\)

C

\(x^2\hat{a}_x + y^2\hat{a}_y + z^2\hat{a}_z\)

D

\(y^2z^2\hat{a}_x + x^2z^2\hat{a}_y + x^2y^2\hat{a}_z\)

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10

2014 · Electrical Engineering · Electromagnetic Fields · Magnetic Fields, Induction and Magnetic Circuits

Electrical Engineering (EE) 2014 [Session 2]

The magnitude of magnetic flux density (\(\vec{B}\)) at a point having normal distance \(d\) meters from an infinitely extended wire carrying current of \(I\) A is \(\frac{\mu_0 I}{2\pi d}\) (in SI units). An infinitely extended wire is laid along the x-axis and is carrying current of 4 A in the +ve x direction. Another infinitely extended wire is laid along the y-axis and is carrying 2 A current in the +ve y direction. \(\mu_0\) is permeability of free space. Assume \(\hat{i}, \hat{j}, \hat{k}\) to be unit vectors along x, y and z axes respectively.
Assuming right handed coordinate system, magnetic field intensity, \(\vec{H}\) at coordinate (2,1,0) will be

A

\(\frac{3}{2\pi} \hat{k}\) weber/m²

B

\(\frac{4}{3\pi} \hat{i}\) A/m

C

\(\frac{3}{2\pi} \hat{k}\) A/m

D

0 A/m

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11

2016 · Electrical Engineering · Electromagnetic Fields · Magnetic Fields, Induction and Magnetic Circuits

Electrical Engineering (EE) 2016 [Session 1]

A soft-iron toroid is concentric with a long straight conductor carrying a direct current \(I\). If the relative permeability \(\mu_r\) of soft-iron is 100, the ratio of the magnetic flux densities at two adjacent points located just inside and just outside the toroid, is __________.

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12

2016 · Electrical Engineering · Electromagnetic Fields · Magnetic Fields, Induction and Magnetic Circuits

Electrical Engineering (EE) 2016 [Session 2]

The flux linkage (λ) and current (i) relation for an electromagnetic system is \( \lambda = \frac{\sqrt{i}}{g} \). When \( i = 2A \) and \( g \) (air-gap length) = 10 cm, the magnitude of mechanical force on the moving part, in N, is ______.

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13

2017 · Electrical Engineering · Electromagnetic Fields · Magnetic Fields, Induction and Magnetic Circuits

Electrical Engineering (EE) 2017 [Session 1]

A solid iron cylinder is placed in a region containing a uniform magnetic field such that the cylinder axis is parallel to the magnetic field direction. The magnetic field lines inside the cylinder will

A

bend closer to the cylinder axis

B

bend farther away from the axis

C

remain uniform as before

D

cease to exist inside the cylinder

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14

2017 · Electrical Engineering · Electromagnetic Fields · Magnetic Fields, Induction and Magnetic Circuits

Electrical Engineering (EE) 2017 [Session 1]

The magnitude of magnetic flux density (B) in micro Teslas (\(\mu T\)), at the center of a loop of wire wound as a regular hexagon of side length 1 m carrying a current (\(I=1\) A), and placed in vacuum as shown in the figure is ______. (Give the answer up to two decimal places.)

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15

2019 · Electrical Engineering · Electromagnetic Fields · Magnetic Fields, Induction and Magnetic Circuits

Electrical Engineering (EE) 2019

The magnetic circuit shown below has uniform cross-sectional area and air gap of 0.2 cm. The mean path length of the core is 40 cm. Assume that leakage and fringing fluxes are negligible. When the core relative permeability is assumed to be infinite, the magnetic flux density computed in the air gap is 1 tesla. With same Ampere-turns, if the core relative permeability is assumed to be 1000 (linear), the flux density in tesla (round off to three decimal places) calculated in the air gap is __________.

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16

2020 · Electrical Engineering · Electromagnetic Fields · Magnetic Fields, Induction and Magnetic Circuits

Electrical Engineering (EE) 2020

A conducting square loop of side length 1 m is placed at a distance of 1 m from a long straight wire carrying a current \(I = 2\) A as shown below. The mutual inductance, in nH (rounded off to 2 decimal places), between the conducting loop and the long wire is ________.

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17

2021 · Electrical Engineering · Electromagnetic Fields · Magnetic Fields, Induction and Magnetic Circuits

Electrical Engineering (EE) 2021

Which one of the following vector functions represents a magnetic field \( \vec{B} \)? ( \( \hat{x}, \hat{y}, \) and \( \hat{z} \) are unit vectors along x-axis, y-axis, and z-axis, respectively)

A

\(10x\hat{x} + 20y\hat{y} - 30z\hat{z} \)

B

\(10y\hat{x} + 20x\hat{y} - 10z\hat{z} \)

C

\(10z\hat{x} + 20y\hat{y} - 30x\hat{z} \)

D

\(10x\hat{x} - 30z\hat{y} + 20y\hat{z} \)

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18

2021 · Electrical Engineering · Electromagnetic Fields · Magnetic Fields, Induction and Magnetic Circuits

Electrical Engineering (EE) 2021

One coulomb of point charge moving with a uniform velocity $10\ \hat{x}$ m/s enters the region $x \geq 0$ having a magnetic flux density $\vec{B} = (10\ y\ \hat{x} + 10\ x\ \hat{y} + 10\ \hat{z})$ T. The magnitude of force on the charge at $x = 0^+$ is ______ N. ($\hat{x}$, $\hat{y}$, and $\hat{z}$ are unit vectors along x-axis, y-axis, and z-axis, respectively.)

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19

2022 · Electrical Engineering · Electromagnetic Fields · Magnetic Fields, Induction and Magnetic Circuits

Electrical Engineering (EE) 2022

A long conducting cylinder having a radius 'b' is placed along the z axis. The current density is \( \mathbf{J} = J_0 r^2 \hat{z} \) for the region \( r < b \) where r is the distance in the radial direction. The magnetic field intensity (H) for the region inside the conductor (i.e. for \( r < b \)) is

A

\(\frac{J_0}{4} r^4 \)

B

\(\frac{J_0}{3} r^3 \)

C

\(\frac{J_0}{5} r^4 \)

D

\(J_0 r^3 \)

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20

2022 · Electrical Engineering · Electromagnetic Fields · Magnetic Fields, Induction and Magnetic Circuits

Electrical Engineering (EE) 2022

If the magnetic field intensity (\(\mathbf{H}\)) in a conducting region is given by the expression, \(\mathbf{H} = x^2 \hat{i} + x^2 y^2 \hat{j} + x^2 y^2 z^2 \hat{k}\) A/m. The magnitude of the current density, in A/m², at \(x = 1\) m, \(y = 2\) m, and \(z = 1\) m, is

A

8

B

12

C

16

D

20

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