Q: An electron is projected into a magnetic field along the lines of force. Then

if \$\vec{v} \parallel \vec{B}\$then \$\theta\$ = 0\$ \implies \vec{F_B}\$ = 0

Q: The force felt by an electron on entering into a magnetic field is independent of its

\$ \vec{F_B} = q \vec{v} \times \vec{B}\$independent of mass

Q: Magnetic field at a point on the line of current carrying conductor is

because angle between line and distance becomes zero.\$\therefore\overrightarrow{l}\times\widehat{r}\$ becomes zero.

Q: A cathode ray beam is bent into an arc of a circle of radius \$0.02 m\$ by a field of magnetic induction \$4.55 mT\$. The velocity of electrons is:(Given \$e=1.6\times 10^{-19}c\$ and \$m=9.1\times 10^{-31}kg\$)

Radius in Magnetic field \$= \dfrac{mV}{eB}\$\$\Rightarrow V = \dfrac{Ber}{m}\$\$\Rightarrow V = \dfrac{4.55 \times 10^{-3} \times 1.6 \times 10^{-19} \times 0.02}{9.1 \times 10^{-31}}\$\$\Rightarrow V = 1.6 \times 10^{7}m/s\$

Q: The magnetic field due to a current element is independent of :

\$B=\dfrac{\mu_o}{4\pi}\dfrac{i\overrightarrow{dl}\times\overrightarrow{r}}{r^3}\$So it depends on all three : current , distance and lengthbut not on nature of material

Q: A neutron , a proton, an electron and an \$\alpha \$ particle enter perpendicular uniform magnetic field, with the same uniform velocity. The path of electron in the following figure will be :

The neutron goes undeflected, the \$\alpha \$ and proton being both positively charged moves towards left and electron being negatively charged moves towards right. or we can also use right hand to find the direction of force using formula \$ F = q(V\times B)\$ but it moves right as \$q\$ is \$-ve.\$

Question 1

An electron is projected into a magnetic field along the lines of force. Then

Accepted Answer

if $\vec{v} \parallel \vec{B}$then $\theta$ = 0$ \implies \vec{F_B}$ = 0

Question 2

When a charged particle moves through a magnetic field, the quantity which is not affected in the magnetic field is:

Accepted Answer

Magnetic field does zero work on moving charged particles. Therefore, kinetic energy of particle remains constant.

Question 3

The force felt by an electron on entering into a magnetic field is independent of its

Accepted Answer

$ \vec{F_B} = q \vec{v} \times \vec{B}$independent of mass

Question 4

The magnetic field  $\overline{dB}$ due to a small current element dl at a distance $\vec{r}$ and carrying current &#8216;i&#8217; is

Accepted Answer

Bio-savert law - apply directly the statement of law

Question 5

When an electron moves through a magnetic field, its speed will

Accepted Answer

The work done by magnetic force on any moving charge particle is zero because magnetic force acts perpendicular to the direction of motion. Therefore speed will remain same.

Question 6

Magnetic field at a point on the line of current carrying conductor is

Accepted Answer

because angle between line and distance becomes zero.$\therefore\overrightarrow{l}\times\widehat{r}$  becomes zero.

Question 7

An electron enters a magnetic field with a speed of $10^{8} cm/s$. The particle experiences a force due to the magnetic field and the speed of the electron

Accepted Answer

A particle travelling perpendicular to a magnetic field would experience a force given by $F=q(\vec{v}\times \vec{B})$.This force, thus, acts perpendicular to the direction of motion of electron. Hence it only changes the direction of electron but not the speed of electron perpendicular to the direction of motion. This force would cause a constant centripetal acceleration. Thus the speed of electron does not change at all.

Question 8

A cathode ray beam is bent into an arc of a circle of radius $0.02 m$ by a field of magnetic induction $4.55 m T$ . The velocity of electrons is:
(Given $e = 1.6 \times 1 0^{- 19} c$ and $m = 9.1 \times 1 0^{- 31} k g$ )

Accepted Answer

Radius in Magnetic field $= \dfrac{mV}{eB}$$\Rightarrow V = \dfrac{Ber}{m}$$\Rightarrow V = \dfrac{4.55 \times 10^{-3} \times 1.6 \times 10^{-19} \times 0.02}{9.1 \times 10^{-31}}$$\Rightarrow V = 1.6 \times 10^{7}m/s$

Question 9

The magnetic field due to a current element is independent of :

Accepted Answer

$B=\dfrac{\mu_o}{4\pi}\dfrac{i\overrightarrow{dl}\times\overrightarrow{r}}{r^3}$So it depends on all three : current , distance and lengthbut not on nature of material

Question 10

A neutron , a proton, an electron and an $\alpha $ particle enter  perpendicular uniform magnetic field, with the same uniform velocity. The path of electron in the following figure will be :

Accepted Answer

The neutron goes undeflected, the $\alpha $ and proton being  both positively charged moves towards left and electron being negatively charged moves towards right. or we can also use right hand to find  the direction of force using formula $ F = q(V\times B)$ but it moves right as $q$ is $-ve.$

Moving Charges And Magnetism

Physics
4234 Views

An electron is projected into a magnetic field along the lines of force. Then

When a charged particle moves through a magnetic field, the quantity which is not affected in the magnetic field is:

The force felt by an electron on entering into a magnetic field is independent of its

The magnetic field $\overline{d B}$ due to a small current element dl at a distance $r$ and carrying current ‘i’ is

When an electron moves through a magnetic field, its speed will

Magnetic field at a point on the line of current carrying conductor is

An electron enters a magnetic field with a speed of $1 0^{8} c m / s$ . The particle experiences a force due to the magnetic field and the speed of the electron

A cathode ray beam is bent into an arc of a circle of radius $0.02 m$ by a field of magnetic induction $4.55 m T$ . The velocity of electrons is:
(Given $e = 1.6 \times 1 0^{- 19} c$ and $m = 9.1 \times 1 0^{- 31} k g$ )

The magnetic field due to a current element is independent of :

A neutron , a proton, an electron and an $α$ particle enter perpendicular uniform magnetic field, with the same uniform velocity. The path of electron in the following figure will be :

Moving Charges And Magnetism

Physics 4234 Views

An electron is projected into a magnetic field along the lines of force. Then

When a charged particle moves through a magnetic field, the quantity which is not affected in the magnetic field is:

The force felt by an electron on entering into a magnetic field is independent of its

The magnetic field dB due to a small current element dl at a distance r and carrying current ‘i’ is

When an electron moves through a magnetic field, its speed will

Magnetic field at a point on the line of current carrying conductor is

An electron enters a magnetic field with a speed of 108cm/s. The particle experiences a force due to the magnetic field and the speed of the electron

A cathode ray beam is bent into an arc of a circle of radius 0.02m by a field of magnetic induction 4.55mT. The velocity of electrons is: (Given e=1.6×10−19c and m=9.1×10−31kg)

The magnetic field due to a current element is independent of :

A neutron , a proton, an electron and an α particle enter perpendicular uniform magnetic field, with the same uniform velocity. The path of electron in the following figure will be :

Physics
4234 Views

The magnetic field $\overline{d B}$ due to a small current element dl at a distance $r$ and carrying current ‘i’ is

An electron enters a magnetic field with a speed of $1 0^{8} c m / s$ . The particle experiences a force due to the magnetic field and the speed of the electron

A cathode ray beam is bent into an arc of a circle of radius $0.02 m$ by a field of magnetic induction $4.55 m T$ . The velocity of electrons is:
(Given $e = 1.6 \times 1 0^{- 19} c$ and $m = 9.1 \times 1 0^{- 31} k g$ )

A neutron , a proton, an electron and an $α$ particle enter perpendicular uniform magnetic field, with the same uniform velocity. The path of electron in the following figure will be :