Drift velocity class 12

When a potential difference is applied across the ends of the conductor, the electric field is generated within the conductor and the free electrons experience force in the opposite direction of the applied electric field. The potential difference applied does not accelerate the electrons but provides a constant velocity in the direction contrary to the electric field generated within the conductor. This small constant velocity is drift velocity. The progression of electric current through materials is caused by the Mobility of charge carriers inside the materials. The free electrons are the charge carriers in the metallic conductors. The students need to distinguish between drift velocity and Mobility. What is the definition of drift velocity? Drift velocity can be considered as the average velocity. In drift velocity, electrons ‘drift’ in the existence of an electric field. It is used to (or drift speed) contributes to the electric current. Indifference, thermal velocity generates random motion, which results in collisions with metal ions. What is the definition of the mobility of an electron? The mobility of an electron can be defined as the drift velocity of an electron for a unit electric field. State the relation Between Drift Velocity and Current Density The current density can be defined as the whole amount of current flowing via a unit cross-sectional conductor in unit time. The formula of drift velocity can be written as:- I = nAvQ J = I/A = nvQ Where, • J stands...

Current Electricity Important Questions for CBSE Class 12 Physics Resistance and Ohm’s Law 1.The directed rate of flow of electric charge through any cross-section of a conductor is known as electric current. where, n = number of charged particles constitute the current NOTE Current is a scalar quantity I is in the direction of flow of positive charge and opposite to the direction of flow of negative charge. SI unit of current is ampere and is represented by A. Ampere is defined as, 2.The current density at a point in a conductor is the ratio of the current at that point in the conductor to the area of cross-section of the conductor at that point provided the area is held normal to the direction of flow of current. NOTE Current density is a vector quantity 3.Flow of Electric Charge in Metallic Conductors Among the solids, all metals are good conductors of electricity. The cause of conductance is free electrons. In Case of a Solid Conductor (i.e. Cu, Fe, Ag, etc) atoms are tightly bound to each other. There are large number of free electrons in them. In Case of a Liquid Conductor Like electrolytic solution, there are positive and negative charged ions which can move on applying electric field. 4.Drift Velocity It is defined as the average velocity with which the free electrons move towards the positive end of a conductor under the influence of an external electric field applied Previous Year Examination Questions 1 Mark Questions 1.Plot a graph showing variation of current ...

Table of content • • • • • • • • • In this comprehensive guide, you'll gain a deep understanding of the concept of drift velocity, Relationship Between Drift Velocity and Electric Current and solved questions and answers for these exams. This concept is crucial for Class 12 Physics and competitive exams like NEET and JEE. It includes detailed explanations, formulae, units, dimensions, derivation and solved examples tailored to your exam preparation needs. Drift Velocity in Conductors Free Electrons in Conductors Metallic conductors are characterized by a large number of free electrons, known as conduction electrons. These electrons are derived from the valence electrons of atoms. At room temperature, conduction electrons move randomly inside the conductor, much like gas molecules. Electron-Ion Collisions During their motion, conduction electrons frequently collide with ions, which are the positively charged atoms left after valence electrons have moved away. The direction of electron motion changes after each collision, causing the electrons to follow a zig-zag path. The Absence of Net Motion in a Neutral Conductor In a conductor, the large number of electrons move randomly. If we imagine an area within the conductor, the number of electrons crossing this area from left to right is nearly equal to the number crossing from right to left in a given time interval. This balanced movement of electrons means that there's no net flow of electric current through that area without ...

Estimate the average drift speed of conduction electrons in a copper wire of cross-sectional area 1 . 0 × 1 0 − 7 m 2 carrying a current of 1 . 5 A. Assume that each copper atom contributes roughly one conduction electron. The density of copper is 9 . 0 × 1 0 3 k g m − 3 and its atomic mass is 6 3 . 5 a m u.

the goal of this video is to derive ohm's law from the microscopic point of view by looking at electrons and this is not a standalone video we have done a lot of work before this in previous videos so we're just going to pick up from where we left off so before we start let's quickly you know recap whatever stuff that we've already seen we saw that paul drouda a german physicist was the first person around 1900s to start giving an explanation a model to explain this and his idea was he treated electrons as tiny tiny particles tiny balls of matter and he said that when you you know when you put when you put a battery there's an electric field that accelerates the electrons but the electrons don't travel in straight lines because there are a lot of crystal ions metal ions over here these electrons are continuously bombarding continuously bouncing off sorry continuously bouncing off these different different ions and so it has a very zigzaggy kind of motion and so here's how we visualized it we electrons are moving with extremely high random velocities thousands of kilometers per second thermal motion we say but that's not going to get them anywhere because they keep bouncing back and forth however in the presence of an electric field we do see that slowly and steadily it starts moving across the conductor and it's this motion that contributes to the electric current and we call this the drifting motion and we figured out what that drifting velocity was and so coming back so ...

\(\begin \) Here, I represents the current flowing through the conductor (in Amperes), n represents the number of electrons, A represents the area of the cross-section of the conductor (m 2), v represents the drift velocity of the electrons, and Q represents the charge of an electron (in Coulomb). Mobility of the Electron The drift velocity of an electron for a unit electric field is known as the mobility of the electron. The mobility of an electron can be calculated by, \(\begin \) Depending on the nature of the charge carrier, mobility is always a positive quantity. Current density is defined as the total amount of current passing per unit cross-sectional area of a conductor. If J is the current density (A/m 2) and v is the drift velocity of the electrons then, \(\begin \) From this formula, electron drift velocity and current density are directly proportional. Furthermore, when the electric field intensity increases, the drift velocity increases and the current flowing through the conductor increases. Read More: Important Questions with Answers 1. What is meant by drift velocity? The average velocity attained by charged particles (e.g. electrons) in a material due to an electric field is called drift velocity. 2. The drift velocity does not depend upon _________. • the length of the wire • the cross-section of the wire • the number of free electrons • the magnitude of the electric field Answer – A. the length of the wire Explanation –The drift velocity does not depend o...