FORCE ON A CHARGE PARTICLE
Introduction to- FORCE ON A CHARGE PARTICLE-12 CBSE
When a charged particle is subjected to an electric field, it experiences a force that is equal to the product of the charge of the particle and the electric field intensity E. The positive charge particles like protons, alpha particles, nuclei, positive ions, etc. experience the force in the direction of the electric field while the negative charge particles like electrons, negative ions, etc. experience the force in the direction opposite to that of the electric field as shown here
A charged particle always experiences force irrespective of the fact that it is stationary or in motion.
MOTION OF A CHARGED PARTICLE INSIDE AN ELECTRIC FIELD-FORCE ON A CHARGE PARTICLE-12 CBSE
Let us suppose that an electric field is established between the two metallic charged plates X-Y plane as shown in the figure below. If V is the potential difference applied to these plates separated by a distance d from each other, then the electric field will be
Consider that a positively charged particle, +q of mass m is projected in the electric field at O with a uniform velocity v. The charged particle, as it enters the field at point O, will move under the combined effect of uniform velocity in x direction and the velocity gained from the electric field and it will go straight as it leaves the field. The horizontal distance ON = x is traveled by the charged particle with uniform velocity v, therefore, the time t to cover this distance is t = x/v ——1
So long as the charged particle remains within the electric field, it is continuously experiencing a force that contribute to its deflection along the OY direction is, F = q E – – – -2 This force acts on the charged particle along OY in Y- axis direction continuously and makes its motion as an accelerated motion so that the acceleration possessed by it, is, Ma = q E => a = q E/m Now the charged particle will cover a distance y along OY so long as it remains in the field, will be
Force on a charge particle moving in a magnetic field-FORCE ON A CHARGE PARTICLE-12 CBSE
Lorentz Force Equation-FORCE ON A CHARGE PARTICLE-12 CBSE
Motion of the charge particle inside a Uniform Magnetic Field
Summary:
- When a charged particle moves in an electric field, it always follows a parabolic path.
- A force is always experienced by a charged particle in an electric field, irrespective of the fact that it is stationary or in motion.
- The force experienced by a charged particle moving in a magnetic field results due to the interaction between the magnetic field produced by the moving charge and the magnetic field applied externally.
- A stationary charge never experiences any force whenever placed in the magnetic field.
- A charged particle experiences a force whenever it moves in a magnetic field in all directions except in the direction parallel to the magnetic field.
- Only, the magnitude of the velocity of a charged particle is affected, when it is moving along the direction of the electric field,
- The direction of the motion is affected when the charge enters the magnetic field obliquely.
- The magnitude of the velocity of a charged particle not affected, when it moves inside the magnetic field. However, its direction of motion changes continuously and so it moves along a circular path.
- When a charged particle enters a magnetic field in a direction perpendicular to the field, then it follows a circular path. In case the charged particle enters the field obliquely, then it follows the helical path due to component of its velocity along the field.
- The helical and spiral paths are quite different from each other. In the cyclotron, the positive ions move inside the D’s along circular path of increasing radii in a plane. Such a path is called Spiral path. When a charge particle moves in a magnetic field which is inclined to its direction of motion, it moves along the circular path due to the component of its velocity perpendicular to the field and at the same time moves forward due to the component of velocity along the field. Such a path followed by the charged particle is called helical path.
- The time period of revolution of a charged particle inside D’s (magnetic field) is independent of the speed and radius of the circular path. It depends upon the value of its charge mass and the strength of the field.
- The acceleration to charged particle is provided only by the electric field. The magnetic field has no effect on velocity or kinetic energy of the charged particle. The magnetic field simply makes the charged particle to cross the electric field again and again by making it to move along circular path.
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