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The strength of earth's magnetic field at a point is $0.4 \times 10^{- 5} T$ . If this field is to be annulled by the magnetic induction produced at the centre of a circular conducting loop of radius $π cm$ , the current to be sent through the loop is

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Important Questions on Moving Charges and Magnetism

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Physics>Electricity and Magnetism>Moving Charges and Magnetism>Magnetic Field on the Axis of a Circular Current Loop

The magnetic field at the centre of a circular coil of

50

turns and radius

10 cm

carrying a current of

1 A,

in tesla is

MEDIUM

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Magnetic Field on the Axis of a Circular Current Loop

Directions: Each of the following sentences in this section has a blank space and four words or group of words given after the sentence. Select the word or group of words you consider most appropriate for the blank space and indicate your response on the Answer Sheet accordingly.

Every rash driver becomes a ____ killer.

EASY

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Magnetic Field on the Axis of a Circular Current Loop

The magnetic field at the centre ${}^{'}O^{'}$ in the given figure is

Question Image

MEDIUM

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Magnetic Field on the Axis of a Circular Current Loop

The coefficient of self-induction of a closely wound coil of

100

turns and area of cross-section

1 {cm}^{2}

1 mH

. Find the magnetic induction at the centre of its core when a current of

2 A

flows in it.

MEDIUM

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Magnetic Field on the Axis of a Circular Current Loop

Two infinitely long wires each carrying current

I

along the same direction are made into the geometry as shown in the figure below.
Question Image

The magnetic field at the point

P

MEDIUM

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Magnetic Field on the Axis of a Circular Current Loop

The magnetic field at the centre $O$ of the current-carrying square loop shown in the figure is

Question Image

HARD

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Magnetic Field on the Axis of a Circular Current Loop

A small circular loop of conducting wire has radius a and carries current

I .

It is placed in a uniform magnetic field

B

perpendicular to its plane such that when rotated slightly about its diameter and released, it starts performing simple harmonic motion of time period

T .

The mass of the loop is

m

then:

EASY

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Magnetic Field on the Axis of a Circular Current Loop

A circular coil of radius

R

carries an electric current

I

. The magnetic field due to the coil at a point on the axis of the coil located at a distance

r

from the centre of the coil, such that

r ≫ R,

the magnetic field at that point is proportional to

EASY

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Magnetic Field on the Axis of a Circular Current Loop

Two sentences are given below and you are required to find the correct sentence which combines both the sentences.

Which is the correct combination of the given two sentences?

He is too tired. He could not stand.

EASY

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Magnetic Field on the Axis of a Circular Current Loop

The magnitude of a magnetic field at the centre of a circular coil of radius

R

, having

N

turns and carrying a current

I

can be doubled by changing

MEDIUM

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Magnetic Field on the Axis of a Circular Current Loop

In the following sentence, a blank space with four options is given. Select whichever preposition or determiner you consider the most appropriate for the blank space.

These are the good rules to live _____.

EASY

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Magnetic Field on the Axis of a Circular Current Loop

A Helmholtz coil has a pair of loops, each with

N

turns and radius

R

. They are placed coaxially at distance

R

and the same current

I

flows through the loops in the same direction. The magnitude of the magnetic field at

P,

midway between the centres

A

and

C,

is given by [Refer to figure given below]:
Question Image

MEDIUM

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Magnetic Field on the Axis of a Circular Current Loop

Let

{\vec{B}}_{1}

is the magnetic field at the centre of the current carrying coil of radius

R

and

{\vec{B}}_{2}

is the magnetic field on the axis of same circular coil at the distance of

3 R .

Then the ratio

\frac{|{\vec{B}}_{1}|}{|{\vec{B}}_{2}|}

EASY

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Magnetic Field on the Axis of a Circular Current Loop

A current

i

flows through a loop as shown in figure. The magnetic field at the Centre

O

MEDIUM

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Magnetic Field on the Axis of a Circular Current Loop

Two circular loops

L_{1}

and

L_{2}

of wire carrying equal and opposite currents are placed parallel to each other with a common axis. The radius of loop

L_{1}

R_{1}

and that of

L_{2}

R_{2}

. The distance between the centres of the loops is

\sqrt{3} R_{1}

. The magnetic field at the centre of

L_{2}

shall be zero if

HARD

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Magnetic Field on the Axis of a Circular Current Loop

A circular coil connected to a battery of emf

E

produced a certain magnetic induction field at its centre. The coil is unwound, stretched to double its length rewound into a coil of

\frac{1^{rd}}{3}

of the original radius and connected to a battery of emf

E^{'}

to produce same field at the centre. Then

E^{'}

EASY

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Magnetic Field on the Axis of a Circular Current Loop

Magnetic field at the centre of a circular loop of area

A

B

. The magnetic moment of the loop will be (

μ_{0} =

permeability of free space)

MEDIUM

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Magnetic Field on the Axis of a Circular Current Loop

A thin ring of

10 c m

radius carries a uniformly distributed charge. The ring rotates at a constant angular speed of

40 π r a d s^{- 1}

about its axis, perpendicular to its plane. Is the magnetic field its centre is

3.8 \times 10^{- 9} T

, then the charge carried by the ring is close to

(μ_{0} = 4 π \times 10^{- 7} N A^{- 2}) .

EASY

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Magnetic Field on the Axis of a Circular Current Loop

An electron moving in a circular orbit of radius

r

makes

n

rotations per second. The magnetic field produced at the center has magnitude:

MEDIUM

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Magnetic Field on the Axis of a Circular Current Loop

A circular coil carrying current

I

has a radius

R

and magnetic field at the centre is

B

. The distance from the centre along the axis of the same coil where the magnetic field will be

\frac{B}{8}

The strength of earth's magnetic field at a point is 0.4×10-5 T. If this field is to be annulled by the magnetic induction produced at the centre of a circular conducting loop of radius πcm, the current to be sent through the loop is

Important Questions on Moving Charges and Magnetism

Learn and Prepare for any exam you want !

The strength of earth's magnetic field at a point is $0.4 \times 10^{- 5} T$ . If this field is to be annulled by the magnetic induction produced at the centre of a circular conducting loop of radius $π cm$ , the current to be sent through the loop is