A uniform electric field and a uniform magnetic field are acting alon...
Explanation:
When an electron is projected into a region where there is a uniform electric field and a uniform magnetic field along the same direction, it experiences both the electric and magnetic forces simultaneously. The direction of the electric force is given by the equation F = qE, where F is the force experienced by the electron, q is the charge of the electron, and E is the electric field. The direction of the magnetic force is given by the equation F = qvB, where v is the velocity of the electron and B is the magnetic field.
Forces acting on the electron:
The electric force and the magnetic force act in the same direction on the electron. This means that the net force on the electron is the sum of these two forces. Since the electron is projected with a velocity along the direction of the fields, there is no initial force acting on the electron perpendicular to its velocity. Therefore, the only forces acting on the electron are the electric and magnetic forces.
Effect of the electric force:
The electric force acts in the same direction as the velocity of the electron. This means that the electric force does not change the magnitude or direction of the electron's velocity. Hence, the speed of the electron remains unchanged.
Effect of the magnetic force:
The magnetic force acts perpendicular to both the velocity of the electron and the magnetic field. Since the magnetic force is perpendicular to the velocity of the electron, it causes the electron to move in a circular path. This circular motion is due to the magnetic force acting as a centripetal force. According to the equation F = mv^2/r, where m is the mass of the electron and r is the radius of the circular path, the magnetic force is given by F = qvB = mv^2/r. From this equation, we can find that r = mv/(qB). Since the velocity of the electron remains constant, the radius of the circular path is inversely proportional to the strength of the magnetic field.
Conclusion:
When an electron is projected into a region with a uniform electric field and a uniform magnetic field along the same direction, the electron moves in a circular path due to the magnetic force acting as a centripetal force. The electric force does not change the magnitude or direction of the electron's velocity. Therefore, the speed of the electron remains constant.
A uniform electric field and a uniform magnetic field are acting alon...
When E, V and B are along same direction, then magnetic force experienced by the electron is zero while electric force is acting opposite to speed of an electron. So, the speed of the electron will decrease.
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