Physics-

General

Easy

### Question

#### A part of a long wire carrying a current is bent into a circle of radius r as shown in figure. The net magnetic field at the centre O of the circular loop is

#### The correct answer is:

#### The magnitude of the magnetic field at point due to straight part of wire is

is perpendicular to the plane of the page, directed upwards (right hand plam rule 1).

The field at the centre due to the current loop of radius is

is also perpendicular to the page, directed upwards (right hand screw rule).

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### Related Questions to study

physics-

#### A wire shown in figure carries a current of 40 A. If , the magnetic field at point will be

Let the given circular part of wire subtends an angle at its centre. Then, magnetic field due to this circular part is

Given,

Given,

#### A wire shown in figure carries a current of 40 A. If , the magnetic field at point will be

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Let the given circular part of wire subtends an angle at its centre. Then, magnetic field due to this circular part is

Given,

Given,

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#### A car covers one third part of its straight path with speed V_{1} and the rest with speed V_{2} . What is its average speed ?

#### A car covers one third part of its straight path with speed V_{1} and the rest with speed V_{2} . What is its average speed ?

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#### A bus travels between two points A and B. V_{1} and V_{2} are it average speed and average velocity then

#### A bus travels between two points A and B. V_{1} and V_{2} are it average speed and average velocity then

physicsGeneral

Maths-

#### If is defined by

#### If is defined by

Maths-General

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#### A car moving over a straight path covers a distance x with constant speed 10ms^{-1} and then the same distance with constant speed of V_{1.}If average speed of the car is , 16 ms^{-1 }then V_{2}=..._{}

#### A car moving over a straight path covers a distance x with constant speed 10ms^{-1} and then the same distance with constant speed of V_{1.}If average speed of the car is , 16 ms^{-1 }then V_{2}=..._{}

physicsGeneral

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#### A copper wire of negligible mass, 1 m length and cross-sectional area is kept on a smooth horizontal table with one end fixed. A ball of mass 1 kg is attached to the other end. The wire and the ball are rotated with an angular velocity 20 radIf the elongation in the wire is , then the Young’s modulus is

Or

#### A copper wire of negligible mass, 1 m length and cross-sectional area is kept on a smooth horizontal table with one end fixed. A ball of mass 1 kg is attached to the other end. The wire and the ball are rotated with an angular velocity 20 radIf the elongation in the wire is , then the Young’s modulus is

physics-General

Or

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#### Two wires of equal cross-section but one made of steel and the other of copper are joined end to end. When the combination is kept under tension, the elongations in the two wires are found to be equal. What is the ratio of the lengths of the two wires? (Given : steel =

Since, cross-sections are equal and same tension exists in both the wires, therefore, the stresses developed are equal.

Also, is given to be the same for both the wires.

#### Two wires of equal cross-section but one made of steel and the other of copper are joined end to end. When the combination is kept under tension, the elongations in the two wires are found to be equal. What is the ratio of the lengths of the two wires? (Given : steel =

physics-General

Since, cross-sections are equal and same tension exists in both the wires, therefore, the stresses developed are equal.

Also, is given to be the same for both the wires.

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#### The relation between and for a elastic material is

#### The relation between and for a elastic material is

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#### If is defined by then

#### If is defined by then

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#### Two long parallel conductors carry currents in opposite directions as shown. One conductor carries a current of 10 A and the distance between the wires is d=10cm Current I is adjusted, so that the magnetic field at P is zero. P is at a distance of 5 cm to the right of the 10 A current. Value of I is

From Biot-Savart’s law the magnetic field due to a conductor carrying current at a distance is

Magnetic field at due to current in second conductor is

From Fleming’s right hands rule the fields at are directed opposite.

Given,

Magnetic field at due to current in second conductor is

From Fleming’s right hands rule the fields at are directed opposite.

Given,

#### Two long parallel conductors carry currents in opposite directions as shown. One conductor carries a current of 10 A and the distance between the wires is d=10cm Current I is adjusted, so that the magnetic field at P is zero. P is at a distance of 5 cm to the right of the 10 A current. Value of I is

physics-General

From Biot-Savart’s law the magnetic field due to a conductor carrying current at a distance is

Magnetic field at due to current in second conductor is

From Fleming’s right hands rule the fields at are directed opposite.

Given,

Magnetic field at due to current in second conductor is

From Fleming’s right hands rule the fields at are directed opposite.

Given,

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#### Two long straight wires are set parallel to each other. Each carries a current in the opposite direction and the separation between them is 2R. The intensity of the magnetic field midway between them is

Magnetic field at mid-point due to wire

Magnetic field at mid-point due to wire

Resultant of Magnetic field

Magnetic field at mid-point due to wire

Resultant of Magnetic field

#### Two long straight wires are set parallel to each other. Each carries a current in the opposite direction and the separation between them is 2R. The intensity of the magnetic field midway between them is

physics-General

Magnetic field at mid-point due to wire

Magnetic field at mid-point due to wire

Resultant of Magnetic field

Magnetic field at mid-point due to wire

Resultant of Magnetic field

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#### A current of 10 A is passing through a long wire which has semicircular loop of the radius 20 cm as shown in the figure. Magnetic field produced at the centre of the loop is

#### A current of 10 A is passing through a long wire which has semicircular loop of the radius 20 cm as shown in the figure. Magnetic field produced at the centre of the loop is

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physics-

#### In the figure shown, the magnetic field induction at the point will be

Field due to a straight wire of infinite length is if the point is on a line perpendicular to its length while at the centre of a semicircular coil is .

out of the page

out of the page

#### In the figure shown, the magnetic field induction at the point will be

physics-General

Field due to a straight wire of infinite length is if the point is on a line perpendicular to its length while at the centre of a semicircular coil is .

out of the page

out of the page

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#### PQ and RS are long parallel conductors separated by certain distance. M is the mid-point between them (see the figure). The net magnetic field at M is B. Now, the current 2A is switched off. The field at M now becomes

Magnetic field at mid-point in first case is

When the current 2 A is switched off, the net magnetic field at is due to current 1 A

When the current 2 A is switched off, the net magnetic field at is due to current 1 A

#### PQ and RS are long parallel conductors separated by certain distance. M is the mid-point between them (see the figure). The net magnetic field at M is B. Now, the current 2A is switched off. The field at M now becomes

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Magnetic field at mid-point in first case is

When the current 2 A is switched off, the net magnetic field at is due to current 1 A

When the current 2 A is switched off, the net magnetic field at is due to current 1 A

physics-

#### Current through ABC and A’ B’ C’ is I. What is the magnetic field at P? (Here C’ B’ PBC are collinear)

Magnetic field

#### Current through ABC and A’ B’ C’ is I. What is the magnetic field at P? (Here C’ B’ PBC are collinear)

physics-General

Magnetic field