A wire of length 10 cm , carrying 10 A current is placed at an angle of 53 ° with respect to a magnetic field of B → of strength 0 . 1 tesla. Find the force experienced by the wire. [Use sin 53 ° = 4 5 .

Magnetic force experienced by the wire is given by F → = I → L × B → . or F = I L B sin θ Given here, length of wire L = 10 cm = 0 . 1 m , current I = 10 A , θ = 53 ° and B = 0 . 1 T . Substituting the given values, we get F = 10 × 0 . 1 × 0 . 1 × sin 53 ° = 0 . 1 × 4 5 = 0 . 08 N .

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A circular coil of $100$ turns and having an effective radius of $0.05 m$ carries a current of $0.1 A$ . How much work is required to turn it in an external magnetic field of $1.5 Wb m^{- 2}$ through $180 °$ about an axis perpendicular to the magnetic field. The plane of the coil is initially perpendicular to the magnetic field

Important Questions on Electromagnetism

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IMPORTANT

A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 8 - Electromagnetism>EXERCISE 8>Q 26

A circular coil of

20

turns and

10 cm

radius is placed in a uniform magnetic field of

0.10 T

normal to the plane of the coil. If the current in the coil is

5.0 A

, find total torque on the coil,

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A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 8 - Electromagnetism>EXERCISE 8>Q 26

A circular coil of

20

turns and

10 cm

radius is placed in a uniform magnetic field of

0.10 T

normal to the plane of the coil. If the current in the coil is

5.0 A

, find total force on the coil

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A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 8 - Electromagnetism>EXERCISE 8>Q 26

A circular coil of

20

turns and radius

10 cm

is placed in a uniform magnetic field of

0 \cdot 10 T

normal to the plane of the coil. If the current in the coil is

5 \cdot 0 A

, what is the average force on each electron in the coil due to the magnetic field?
(The coil is made of copper wire of cross-sectional area

10^{- 5} m^{2}

and the free electron density in copper is given to be about

10^{29} m^{- 3}

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A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 8 - Electromagnetism>EXERCISE 8>Q 27

A straight wire of length

L

, carrying a current

I

, stays suspended horizontally in the mid-air in a region where there is a uniform magnetic field

\vec{B}

. The linear mass density of the wire is

λ

. Obtain the magnitude and direction of this force

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A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 8 - Electromagnetism>EXERCISE 8>Q 28

In a hydrogen atom, an electron of charge

e

revolves in an orbit of radius

r

with speed

v

. Prove that the magnetic moment associated with the electron is given by

\frac{e v r}{2}

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A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 8 - Electromagnetism>EXERCISE 8>Q 29

In a Thomson set-up for finding

\frac{e}{m}

, the electrons are accelerated through a potential of

2500 V

. The electrons then enter a region of cross electric and magnetic fields of magnitude

3.6 \times 10^{4} V m^{- 1}

and

1.2 \times 10^{- 3} T

respectively and pass through undeviated. Calculate the

\frac{e}{m}

of the electrons.

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A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 8 - Electromagnetism>EXERCISE 8>Q 30

A wire of length

10 cm

, carrying

10 A

current is placed at an angle of

53 °

with respect to a magnetic field of

\vec{B}

of strength

0.1

tesla. Find the force experienced by the wire. [Use

\sin 53 °

= \frac{4}{5}

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IMPORTANT

A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 8 - Electromagnetism>EXERCISE 8>Q 31

An electron beam passes through a region in which a magnetic field of

2 \times 10^{- 3} T

and an electric field

3.4 \times 10^{4} V /

m

both acting simultaneously at right angle to each other. If the path of the electron remains undeflected, calculate the speed of the electrons. If the electric field is removed what will be radius of the circular path of electrons? (Mass and charge of the electron are

9.1 \times 10^{- 31} kg

and

1.6 \times 10^{- 19} C

respectively.

Important Questions on Electromagnetism

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