If the magnetic flux through a circuit changes, an emf and a current are induced. This concept of motional emf can be explained with the help of the concept of lorentz force acting on free charge carriers of the conductor. The magnetic field b is into the page, perpendicular to the moving rod and rails and, hence, to the area enclosed by them. Consider a rod of length is placed on two parallel metal rails. In fact, a loop is only needed if we want the induced current i. Ap physics c derivation of motional emf using faradays law of induction. Motional emf as electrical power conversion for the space shuttle was the motivation for the tethered satellite experiment. The polarity of the induced emf is such that it tends to produce a current that creates a magnetic flux to oppose the change in magnetic flux through the area.
As the rod moves with a constant speed v, the charge is also moving with a speed v in the presence of magnetic field b. Class 12 physics chapter wise derivation list edurev. The emf induced by the motion of a conductor across a magnetic field is called motional emf. This equation is true as long as the velocity, field, and length are mutually perpendicular.
G now suppose the conducting bar moves through a region of uniform magnetic field b. Let us consider any arbitrary charge q in the conductor pq. Introduces the physics of motional emf which is an application of faradays law. Braingenie solving problems involving motional emf using. Page 1 chapter wise theoretical important questions in physics for classxii page 1 electrostatics 1. From faradays law consider a conducting bar sliding frictionlessly on a ushaped wire at constant velocity to the right. Consider a conducting bar of length l moving through a uniform magnetic field which points into the page, as shown in figure 10. Motional emf and application of faradays law youtube. Actually in electrical power transformer, one alternating electrical source is applied to the primary winding and due to this, magnetizing current flowing through the primary winding which produces alternating flux in the core of transformer. Improve your skills with free problems in solving problems involving motional emf using the equation emf vbl and thousands of other practice lessons. This flux links with both primary and secondary windings.
Emf equation of transformer turns voltage transformation. We know that an emf is produced in the loop when the amount of magnetic flux linked with the circuit os changed. Emf equation of transformer can be established in a very easy way. Dragging a wire through a magnetic field can make a current. A 5kv emf was predicted to be induced in the 20km tether while moving at orbital speed in earths magnetic field. The circuit is completed by a return path through the stationary ionosphere. E vbl where v, b, and l are all perpendicular to each other if the left vertical side of the spinning coil moves at velocity v, the component of v perpendicular to b is v sin. Students may erroneously believe we need a complete loop to get. Changing the magnetic flux through a circuit can make a current.
Consider the following classical example of a slidewire generator which consists of ushaped. Deriving expression for motional emf stack exchange. In general, motional emf around a closed conducting loop can be written as. An emf induced by the motion of the conductor across the magnetic field is a motional electromotive force. We all know that when an electrical conductor is introduced into a magnetic field, due to its dynamic interaction. G k pointing into the page by sliding along two frictionless conducting rails that. A galvanometer is connected between two ends of the rails to detect the current flowing due to electromagnetic induction. Motional emf, electromotive force, induced emf definition and. Electromagnetic induction the physics hypertextbook.