An electron is travelling horizontally towards east. A magnetic field is vertically downward direction exerts a force on the electron in the direction ofa)Northb)Southc)Eastd)WestCorrect answer is option 'B'. Can you explain this answer?

Question

Answer

South

Answer

Fleming's left hand rule
forefinger -magnetic field
middle finger - velocity
thumb - force
in the case of electron direction of velocity is taken as the opposite of given direction

Answer

We know, F= -e (V×B).

where F is magnetic force vector, v is velocity vector { it shows direction of motion of charged particle } and B is magnetic field vector.

now, use flaming left hand rule , we get, direction of magnetic force vector is along south.

hence, force exerted on the electron along South.

Answer

The direction of the force experienced by a charged particle moving through a magnetic field can be determined by applying the right-hand rule. In this case, the electron is moving horizontally towards the east, and the magnetic field is vertically downward.

Right Hand Rule:
1. Thumb: Point your right thumb in the direction of the velocity of the charged particle (east in this case).
2. Index Finger: Point your right index finger in the direction of the magnetic field (vertically downward).
3. Middle Finger: The direction in which your middle finger points represents the direction of the force acting on the charged particle.

By applying the right-hand rule, we find that the force on the electron is directed towards the south. Hence, the correct answer is option 'B' - South.

Explanation:
1. Velocity of the Electron: The electron is moving horizontally towards the east. This means that its velocity vector points towards the east.
2. Magnetic Field: The magnetic field is vertically downward. This means that its direction is perpendicular to the direction of the electron's velocity.
3. Force on the Electron: When a charged particle moves through a magnetic field, it experiences a force that is perpendicular to both its velocity and the magnetic field. The force is given by the equation:

F = q * v * B * sin(theta)

where:
- F is the force on the electron,
- q is the charge of the electron,
- v is the velocity of the electron,
- B is the magnetic field strength, and
- theta is the angle between the velocity vector and the magnetic field vector.

In this case, since the electron's velocity is perpendicular to the magnetic field (theta = 90 degrees), the term sin(theta) becomes 1. Therefore, the force on the electron simplifies to:

F = q * v * B

Since the electron is negatively charged, the force acts in the opposite direction to the velocity vector.

By applying the right-hand rule, we can determine the direction of the force on the electron.

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