The magnetic field at the origin due to a current element i d l → placed at a point with vector position r → is

μ 0 i 4 π r → × d l → r 3

μ 0 i 4 π d l → × r → r 2

μ 0 i 4 π r → × d l → r 2

- μ 0 i 4 π d l → × r → r 4

EASY

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What is a current element?

Important Questions on Electromagnetism

EASY

Physics>Electricity and Magnetism>Electromagnetism>Biot-Savart Law

What is the current in a straight wire. if a magnetic field of

10^{- 6} W m^{- 2}

is produced at a distance of

2 cm

from it?

MEDIUM

Physics>Electricity and Magnetism>Electromagnetism>Biot-Savart Law

One of the two identical conducting wires of length

L

is bent in the form of a circular loop and the other one into a circular coil of

N

identical turns. If the same current is passed in both, the ratio of the magnetic field at the centre of the loop

(B_{L})

to that at the centre of the coil

(B_{C}),

i.e.

\frac{B_{L}}{B_{C}}

will be

EASY

Physics>Electricity and Magnetism>Electromagnetism>Biot-Savart Law

A square loop is made from a uniform wire as shown in the figure. If a battery is connected between the points $A & C,$ then the magnitude of the magnetic field at the center of the square is

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HARD

Physics>Electricity and Magnetism>Electromagnetism>Biot-Savart Law

With the help of Biot-Savart law derive the expression for the intensity of magnetic field at a point due to an infinitely long straight conductor carrying current.

EASY

Physics>Electricity and Magnetism>Electromagnetism>Biot-Savart Law

The magnetic field at the origin due to a current element

i

d \vec{l}

placed at a point with vector position

\vec{r}

MEDIUM

Physics>Electricity and Magnetism>Electromagnetism>Biot-Savart Law

Write Biot-Savart's law in vector form.

EASY

Physics>Electricity and Magnetism>Electromagnetism>Biot-Savart Law

The C.G.S. unit of magnetic field at a point, due to Biot-Savart law is

EASY

Physics>Electricity and Magnetism>Electromagnetism>Biot-Savart Law

Write the name of any two rules to find the direction of magnetic field.

HARD

Physics>Electricity and Magnetism>Electromagnetism>Biot-Savart Law

A non-conducting thin disc of radius

R

rotates about its axis with an angular velocity

w

. The surface charge density on the disc varies with the distance

r

from the center as

σ (r) = σ_{0} [1 + {(\frac{r}{R})}^{β}]

, where

σ_{0}

and

β

are constants. If the magnetic induction at the center is

B = (\frac{9}{10}) μ_{0} σ_{0} w R

, the value of

β

EASY

Physics>Electricity and Magnetism>Electromagnetism>Biot-Savart Law

The correct Biot-Savart's law in vector form is

MEDIUM

Physics>Electricity and Magnetism>Electromagnetism>Biot-Savart Law

Write Bio-Savart law in vector form and mentioned the direction of the magnetic field. Which term in the law work as a vector field and produces a magnetic field? Mention one similarity and one dissimilarity between Bio-Savart law for magnetic field and Coulomb’s law for electrostatics.

MEDIUM

Physics>Electricity and Magnetism>Electromagnetism>Biot-Savart Law

A cylindrical conductor of radius

R

is carrying a constant current. The plot of the magnitude of the magnetic field

B

with the distance

d

from the centre of the conductor is correctly represented by the figure.

MEDIUM

Physics>Electricity and Magnetism>Electromagnetism>Biot-Savart Law

What is Biot-Savart's law?

EASY

Physics>Electricity and Magnetism>Electromagnetism>Biot-Savart Law

Two thin metallic wires lie on $X$ and $Y$ -axes and both carry the same current as shown in the figure below. $A B$ and $C D$ are the two lines making angles $45 °$ with the axes and the origin of axes is $O$ . The magnetic field will be zero

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MEDIUM

Physics>Electricity and Magnetism>Electromagnetism>Biot-Savart Law

Write Biot-Savart law.

EASY

Physics>Electricity and Magnetism>Electromagnetism>Biot-Savart Law

Two similar insulated wires are bent in the form of a circle of radius $1 cm$ carrying $1 A$ current each in the direction shown as in figure $- I$ and figure $- II$ . Which one will have stronger magnetic field at the centre $O$ ? Justify.

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