Magnetic Field of Straight Wires · Long straight wire
A straight long wire is carrying current I. The ratio of magnetic field due to this wire at perpendicular distance 2 cm and 5 cm respectively from the wire is
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Answer: (d)
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Magnetic Field of Straight Wires · Long straight wire
A straight long wire is carrying current I. The ratio of magnetic field due to this wire at perpendicular distance 2 cm and 5 cm respectively from the wire is
Answer: (d)
Magnetic Field of Straight Wires · Long straight wire
The magnetic field at a distance 'r' from a long straight wire carrying current I is 0.4 tesla. The magnetic field at a distance 2r will be
Answer: (b)
Magnetic Field of Straight Wires · Long straight wire
The magnetic field at perpendicular distance '' from a long wire carrying current '' is ''. The magnetic field at perpendicular distance '' from the same wire is
Answer: (b)
Magnetic Field of Straight Wires · Two wires: resultant field
Two parallel wires of equal lengths are separated by a distance of m from each other. The currents flowing through first and second wire is A and A respectively in opposite directions. The resultant magnetic field at mid point of both the wires is ( = permeability of free space)
Answer: (a)
Magnetic Field of Straight Wires · Two wires: resultant field
Two long straight parallel wires are separated by a distance of cm. Each wire carries current mA in the same direction. The magnetic field at a point P midway between them is permeability of free space
Answer: (d)
Magnetic Field of Straight Wires · Two wires: resultant field
Two parallel wires of equal lengths are separated by a distance of m from each other. The currents flowing through first and second wire is A and A respectively in opposite directions. The resultant magnetic field at mid point of both the wires is (=permeability of free space)
Answer: (b)
Magnetic Field of Straight Wires · Two wires: resultant field
A current of 30 A each flows in opposite directions in two conducting wires, placed parallel to each other at a distance of 8 cm. The magnetic field at the mid point between the two wires is
Answer: (b)
Magnetic Field of Straight Wires · Two wires: resultant field
Two parallel long wires carry currents and with . When the currents are in the same direction, the magnetic field at a point midway between the wires is T. If the direction of is reversed then the field becomes T. The ratio
Answer: (c)
Magnetic Field of Straight Wires · Two wires: resultant field
Two long parallel wires carrying currents A and A in opposite directions are placed at a distance of cm from each other. A point P is at equidistant from both the wires such that the lines joining the point P to the wires are perpendicular to each other. The magnetic field at P is ___ T. (Given: SI unit)
Answer: (c)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
In the following figure, the magnitude of the magnetic field at point 'O' will be

Answer: (c)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
The magnitude of magnetic induction at mid point 'O' due to current arrangement as shown in figure will be ( = permeability of free space)

Answer: (d)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
Two identical long current carrying wires are bent into the shapes shown in the following figures. If the magnitude of magnetic fields at the centres P and Q of a semicircular arc are and respectively, then the ratio is ______.

Answer: (a)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
An infinitely long straight wire carrying current is bent in a planar shape as shown in the diagram. The radius of the circular part is . The magnetic field at the centre of the circular loop is:

Answer: (b)
Magnetic Field of Straight Wires · Finite wire & polygon loops
The current passing through a conducting loop in the form of equilateral triangle of side is 2 A. The magnetic field at its centroid is . The value of is ______.
(Given: SI units)
Answer: (a)
Magnetic Field of Straight Wires · Two wires: resultant field
Two long parallel wires carry currents and . When currents are flowing in the same direction, the magnetic field at a point midway between the wires is . If the direction of is reversed the field at midpoint becomes . The ratio is
Answer: (a)
Magnetic Field of Straight Wires · Two wires: resultant field
Two very long straight conductors (wires) are set parallel to each other. Each carries a current ' I ' in the same direction and the separation between them is ' 2 r '. The intensity of the magnetic field at point ' P ' (as shown in the figure) ( permeability of free space) is

Answer: (a)
Magnetic Field of Straight Wires · Two wires: resultant field
Two identical long parallel wires carry currents ' ' and ' ' such that . When the currents are in the same direction, the magnetic field at a point midway between the wires is . If the direction of is reversed, the field becomes . The ratio of to is
Answer: (c)
Magnetic Field of Straight Wires · Two wires: resultant field
Two long parallel wires carrying currents 4 A and 3 A in opposite directions are placed at a distance of 5 cm from each other. A point P is at equidistance from both the wires such that the line joining the point P to the wires are perpendicular to each other. The magnitude of magnetic field at point is ( permeability of free space SI unit)
Answer: (d)
Magnetic Field of Straight Wires · Two wires: resultant field
Two long parallel wires and , separated by a distance of 6 cm, carry currents of 5 A and 4A, respectively, in opposite directions as shown in the figure. Magnitude of the resultant magnetic field at point P at a distance of 4 cm from wire Y is . The value of is _________. Take permeability of free space as SI units.

Numerical answer type. Work it out, then open the answer.
Answer: 1
Magnetic Field of Straight Wires · Bent wires & wire with a loop
An infinitely long straight conductor carrying current ' ' is bent into a shape as shown in figure. The radius of the circular loop is ' '. The magnetic induction at the centre of the loop at point ' O ' is ( permeability of free space)

Answer: (d)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
In the following figure magnitude of the magnetic field at the point is

Answer: (c)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
A current ' I ' is flowing in a conductor PQRST as shown in figure. The radius of curved path QRS is ' R ' and length of straight portion PQ and ST is very large. The magnetic field at the centre of the curved part is ( permeability of free space)

Answer: (b)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
A wire has three different sections as shown in figure. The magnitude of the magnetic field produced at the centre ' ' of the semicircle by three sections together is ( permeability of free space)

Answer: (a)
Magnetic Field of Straight Wires · Bent wires & wire with a loop

An infinite wire has a circular bend of radius a, and carrying a current I as shown in the figure. The magnitude of magnetic field at the origin O of the arc is given by:
Answer: (b)
Magnetic Field of Straight Wires · Finite wire & polygon loops
Figure shows a current carrying square loop ABCD of edge length ‘a’ lying in a plane. If the resistance of the ABC part is r and that of ADC part is 2r, then the magnitude of the resultant magnetic field at centre of the square loop is

Answer: (b)
Magnetic Field of Straight Wires · Finite wire & polygon loops
A current of 5 A exists in a square loop of side . Then the magnitude of the magnetic field at the centre of the square loop will be . where, value of p is ________ Take ].
Numerical answer type. Work it out, then open the answer.
Answer: 8
Magnetic Field of Straight Wires · Long straight wire
The strength of magnetic field at a perpendicular distance ' ' near a long straight conductor carrying current ' I ' is ' B '. The magnetic field at a distance from straight conductor will be
Answer: (b)
Magnetic Field of Straight Wires · Two wires: resultant field
Two long straight parallel wires are separated by a distance '2d'. Each wire carries a current 'I' in the same direction. The magnetic field at a point 'P' midway between them is
Answer: (b)
Magnetic Field of Straight Wires · Two wires: resultant field
Two long, straight wires carry equal currents in opposite directions as shown in figure. The separation between the wires is . The magnitude of the magnetic field at a point midway between the wires is _______
(Given: )

Numerical answer type. Work it out, then open the answer.
Answer: 160
Magnetic Field of Straight Wires · Two wires: resultant field
Two parallel long current carrying wires separated by a distance are shown in the figure. The ratio of magnetic field at to the magnetic field produced at is . The value of is __________.

Numerical answer type. Work it out, then open the answer.
Answer: 5
Magnetic Field of Straight Wires · Bent wires & wire with a loop
An infinitely long straight conductor carrying current 'I' is bent in a shape as shown in figure. The radius of the circular part of loop is 'r'. The magnetic induction at the centre 'C' is ( permeability of free space)

Answer: (c)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
A current carrying circular loop of radius ' ' and current carrying long straight wire are placed in the same plane. The current through circular loop and long straight wire are ' ' and ' ' respectively. The perpendicular distance between centre of the circular loop and wire is ' d '. The magnetic field at the centre of the loop will be zero when separation ' ' is equal to
Answer: (a)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
The magnitude of magnetic field at point 'O' in the following figure will be

Answer: (c)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
A current carrying circular loop of radius ' ' and current carrying long straight wire are placed in the same plane. and are the currents through circular loop and long straight wire respectively. The perpendicular distance between centre of the circular loop and wire is ' d '. The magnetic field at the centre of the loop will be zero when separation ' ' is equal to
Answer: (a)
Magnetic Field of Straight Wires · Finite wire & polygon loops
A regular polygon of 6 sides is formed by bending a wire of length meter.
If an electric current of A is flowing through the sides of the polygon, the magnetic field at the centre of the polygon would be .
The value of is _________.
Numerical answer type. Work it out, then open the answer.
Answer: 72
Magnetic Field of Straight Wires · Finite wire & polygon loops
A current of flows in a square loop of side placed in air. The magnetic field at the centre of the loop is . The value of is _________.
Numerical answer type. Work it out, then open the answer.
Answer: 40
Magnetic Field of Straight Wires · Long straight wire
The magnetic field at a point situated at perpendicular distance '' from a long straight wire carrying a current of is . The value of '' in is
Answer: (d)
Magnetic Field of Straight Wires · Two wires: resultant field
Two parallel wires of equal lengths are separated by a distance of from each other. The currents flowing through st and nd wire is and 4.5 A respectively in opposite directions. The resultant magnetic field at mid point between the wires permeability of free space)
Answer: (d)
Magnetic Field of Straight Wires · Two wires: resultant field
Two long parallel wires carrying currents and in opposite directions are placed at a distance of from each other. A point '' is at equidistant from both the wires such that the lines joining the point to the wires are perpendicular to each other. The magnitude of magnetic field at point '' is SI units)
Answer: (a)
Magnetic Field of Straight Wires · Two wires: resultant field
Two long parallel wires carrying currents 8A and 15A in opposite directions are placed at a distance of 7 cm from each other. A point P is equidistant from both the wires such that the lines joining the point P to the wires are perpendicular to each other. The magnitude of magnetic field at P is _____________ T.
(Given: )
Numerical answer type. Work it out, then open the answer.
Answer: 68
Magnetic Field of Straight Wires · Bent wires & wire with a loop
A very long conducting wire is bent in a semi-circular shape from to as shown in figure. The magnetic field at point for steady current configuration is given by:

Answer: (b)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
As shown in the figure, a long straight conductor with semicircular arc of radius m is carrying current . The magnitude of the magnetic field, at the center O of the arc is: (The permeability of the vacuum )

Answer: (b)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
Find the magnetic field at the point in figure. The curved portion is a semicircle connected to two long straight wires.

Answer: (a)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
The magnitude of magnetic induction at mid point due to current arrangement as shown in Fig will be

Answer: (a)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
Match List I with List II
Choose the correct answer from the options given below:
| List I (Current configuration) | List II (Magnitude of Magnetic Field at point O) | ||
| A. | I. | ||
| B. | II. | ||
| C. | III. | ||
| D. | IV. |
Answer: (c)
Magnetic Field of Straight Wires · Finite wire & polygon loops
As shown in the figure, a current of flowing in an equilateral triangle of side . The magnetic field at the centroid of the triangle is

(Neglect the effect of earth's magnetic field)
Answer: (c)
Magnetic Field of Straight Wires · Two wires: resultant field
Two parallel conducting wires of equal length are placed distance 'd' apart, carry currents ' ' and '' respectively in opposite directions. The resultant magnetic field at the midpoint of the distance between both the wires is
Answer: (d)
Magnetic Field of Straight Wires · Two wires: resultant field
Two long current carrying conductors are placed parallel to each other at a distance of 8 cm between them. The magnitude of magnetic field produced at mid-point between the two conductors due to current flowing in them is 300 T. The equal current flowing in the two conductors is:
Answer: (b)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
In the following loop, magnitude of the magnetic field produced at the centre (O) of the loop is: (Assume AB and CD are infinitely extended):

Answer: (c)
Magnetic Field of Straight Wires · Long straight wire
A straight wire of diameter carrying a current of is replaced by another wire of 0.8 diameter carrying the same current. The magnetic field at distance from both the wires is 'B' and 'B' respectively. The relation between B and B is
Answer: (b)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
There are two infinitely long straight current carrying conductors and they are held at right angles to each other so that their common ends meet at the origin as shown in the figure given below. The ratio of current in both conductor is 1: 1. The magnetic field at point P is ____________.

Answer: (a)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
A hairpin like shape as shown in figure is made by bending a long current carrying wire. What is the magnitude of a magnetic field at point P which lies on the centre of the semicircle?

Answer: (c)
Magnetic Field of Straight Wires · Finite wire & polygon loops
A current of 1.5 A is flowing through a triangle, of side 9 cm each. The magnetic field at the centroid of the triangle is:
(Assume that the current is flowing in the clockwise direction.)
Answer: (d)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
A circular coil of radius is carrying a current in anti-clockwise sense. A long straight wire is carrying current in the negative direction of -axis. Both are placed in the same plane and the distance between centre of coil and straight wire is . The magnetic field at the centre of coil will be zero for the value of equal to
Answer: (a)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
A very long wire ABDMNDC is shown in figure carrying current I. AB and BC parts are straight, long and at right angle. At D wire forms a circular turn DMND of radius R. AB, BC parts are tangential to circular turn at N and D. Magnetic field at the centre of circle is:

Answer: (d)
Magnetic Field of Straight Wires · Finite wire & polygon loops
Magnitude of magnetic field (in SI units) at the centre of a hexagonal shape coil of side 10 cm, 50 turns and carrying current I (Ampere) in units of is:
Answer: (c)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
Figure show the circular coil carrying current kept very close but not touching at a point on a straight conductor carrying the same current . The magnitude of magnetic induction at the centre of the circular coil will be

Answer: (a)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
Two very long, straight, and insulated wires are kept at 90° angle from each other in xy-plane as shown in the figure. These wires carry currents of equal magnitude I, whose directions are shown in the figure. The net magnetic field at point P will be:

Answer: (c)
Magnetic Field of Straight Wires · Finite wire & polygon loops
Find the magnetic field at point P due to a straight line segment AB of length 6 cm carrying a current of 5A. (See figure) (0 = 4 × 10–7 N-A–2)

Answer: (a)
Magnetic Field of Straight Wires · Finite wire & polygon loops
The magnitude of the magnetic field at the centre of an equilateral triangular loop of side 1 m which is carrying a current of 10 A is:
[Take 0 = 4 × 10–7 NA–2]
Answer: (b)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
As shown in the figure, two infinitely long, identical wires are bent by 90° and placed in such a way that the segments LP and QM are along the x-axis, while segments PS and QN are parallel to the y- axis. If OP = OQ = 4cm, and the magnitude of the magnetic field at O is 10–4 T, and the two wires carry equal currents (see figure), the magnitude of the current in each wire and the direction of the magnetic field at O will be (0 = 4 10–7 NA–2):

Answer: (c)
Magnetic Field of Straight Wires · Finite wire & polygon loops
A current of 1 A is flowing on the sides of an equilateral triangle of side 4.5 10-2 m. The magnetic field at the center of the triangle will be:
Answer: (d)
Magnetic Field of Straight Wires · Finite wire & polygon loops
Two identical wires and each of length , carry the same current . Wire is bent into a circle of radius and wire is bent to form a square of side . If and are the values of magnetic fields at the centres of the circle and square respectively, then the ratio is:
Answer: (b)
Magnetic Field of Straight Wires · Bent wires & wire with a loop
A wire carrying current has the shape shown in adjoining figure.

Linear parts of the wire are very long and parallel to X-axis while semicircular protion of radius R is lying in Y-Z plane. Magtnetic field at pont is
Answer: (a)
Magnetic Field of Straight Wires · Two wires: resultant field
Two identical long conducting wires and are placed at right angle to each other, with one above other such that is their common point for the two. The wires carry 1 and 2 currents, respectively. Point is lying at distance f from along a direction perpendicular to the plane containing the wires. The magnetic field at the point will be
Answer: (d)
Magnetic Field of Straight Wires · Finite wire & polygon loops
A current is flowing in a straight conductor of length . The magnetic induction at a point on its axis at a distance from its centre will be:
Answer: (a)
Magnetic Field of Straight Wires · Two wires: resultant field
Two long parallel wires are at a distance apart. They carry steady equal currents flowing out of the plane of the paper as shown. The variation of the magnetic field along the line is given by
Answer: (a)
Magnetic Field of Straight Wires · Long straight wire
A horizontal overhead powerline is at height of from the ground and carries a current of from east to west. The magnetic field directly below it on the ground is
Answer: (c)
Magnetic Field of Straight Wires · Two wires: resultant field
Two identical conducting wires and are placed at right angles to each other. The wire carries an electric current and carries a current . The magnetic field on a point lying at a distance from , in a direction perpendicular to the plane of the wires and , will be given by
Answer: (c)
Magnetic Field of Straight Wires · Two wires: resultant field
The magnetic field at centre, P will be

Answer: (c)
Magnetic Field of Straight Wires · Long straight wire
A straight wire of diameter carrying a current of is replaced by another wire of diameter carrying the same current. The strength of magnetic field far away is
Answer: (d)
Magnetic Field of Straight Wires · Long straight wire
A straight wire of diameter carrying a current of is replaced by the another wire of diameter carrying the same current. The strength of the magnetic field far away is
Answer: (d)
Magnetic Field of Straight Wires · Two wires: resultant field
Two equal electric currents are flowing perpendicular to each other as shown in the figure. and are perpendicular to each other and symmetrically placed with respect to the currents. Where do we expect the resultant magnetic field to be zero?

Answer: (b)
Magnetic Field of Straight Wires · Long straight wire
The magnetic field at a distance from a long wire carrying current is tesla. The magnetic field at a distance is
Answer: (a)
Magnetic Field of Straight Wires · Long straight wire
The magnetic induction at a point which is at the distance of from a long current carrying wire is . The field of induction at a distance from the current will be
Answer: (a)
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