Question

Imagine that you are sitting in a chamber with your back to one wall. An electron
beam, moving horizontally from back wall towards the front wall, is deflected by a
strong magnetic field to your right side. What is the direction of magnetic field?

Class = 8th

Points = 15 ☺☻☺

Answer 1

Given:

An electron comingfrom back wall moving horizontally towards the front wall is deflected on the right side due to presence of a strong magnetic.

To find:

Direction of the magnetic field

Calculation:

Force experienced by an electron in a magnetic field is :

$\therefore \: force = q \times v \times B$

$= > \: force = e \times v \times B$

$= > \: force = e v B$

Direction of the force is given by the Left Hand Thumb rule for an negative charge (electron):

FOLLOW THE STEPS:

• Direction of Velocity of electron is forward

• Direction of force is rightward

• Move the fore fingers of left had from the direction of Velocity to Magnetic field such that the thumb directs rightward.

• It is possible only if the magnetic field is downwards.

So, final answer is:

Magnetic Field is directed downwards.

Answer 2

Explanation:

An electron comingfrom back wall moving horizontally towards the front wall is deflected on the right side due to presence of a strong magnetic.

To find:

Direction of the magnetic field

Calculation:

Force experienced by an electron in a magnetic field is :

\therefore \: force = q \times v \times B∴force=q×v×B

= > \: force = e \times v \times B=>force=e×v×B

= > \: force = e v B=>force=evB

Direction of the force is given by the Left Hand Thumb rule for an negative charge (electron):

FOLLOW THE STEPS:

Direction of Velocity of electron is forward

Direction of force is rightward

Move the fore fingers of left had from the direction of Velocity to Magnetic field such that the thumb directs rightward.

It is possible only if the magnetic field is downwards.

So, final answer is:

Magnetic Field is directed downwards.