as you increase the magnetic field, an electron gets curved towards edge of the sample . this create a potential difference at opposite edges of the sample, which opposes the cause. since magnetic field increases the potential so the resistance increases as resistance is V/I.
How does resistance change with magnetic field?
Applying a magnetic field can also increase the resistance of a material, since the magnetic force on the moving charges will tend to increase the number of collisions between charges. ... Magnetoresistance is proportional to the strength of the magnetic field, with a larger field producing a higher resistance.
Why do magnetic fields resist change?
Lenz’s law states that the current induced in a circuit due to a change in a magnetic field is directed to oppose the change in flux and to exert a mechanical force which opposes the motion. ... This means that the direction of the back EMF of an induced field opposes the changing current that is its cause.
Why do inductors resist change in current?
Inductors react against changes in current by dropping voltage in the polarity necessary to oppose the change . When an inductor is faced with an increasing current, it acts as a load: dropping voltage as it absorbs energy (negative on the current entry side and positive on the current exit side, like a resistor).
Why do magnetic fields not work?
If you look at a classical charged particle (no intrinsic magnetism) moving in a magnetic field, the magnetic field does no work on it directly. You know that because the force is proportional to vXB, where v is the particle velocity. ... Work gets done on it.
What increases magnetic field?
The strength of the magnetic field around a solenoid can be increased by: increasing the number of turns on the coil . increasing the current .
How do you find the resistance of a magnetic field?
The resistance of a metal is in general increased by a magnetic field. For sufficiently small magnetic fields this dependence may, of course, be expressed by the equation ∆R/R = BH 2 .
How can you tell when a magnetic field is the strongest?
The magnetic field of a bar magnet is strongest at either pole of the magnet . It is equally strong at the north pole when compared with the south pole. The force is weaker in the middle of the magnet and halfway between the pole and the center.
Can a magnetic field accelerate a charged particle?
Velocity, magnetic field and force are perpendicular to each other. So it can change the direction of the velocity of a charged particle. So our answer is Yes, a charged particle can be accelerated by a magnetic filed but its speed can’t be increase.
What happens to the magnetic field in the solenoid when the number of turns increases?
What happens to the magnetic field in the solenoid when the number of turns increases? Explanation: The magnetic field of a solenoid is directly proportional to the number of turns in it . Hence as the number of turns increases, the magnetic field also increases.
What does an inductor do to current?
Inductors are typically used as energy storage devices in switched-mode power devices to produce DC current. The inductor, which stores energy, supplies energy to the circuit to maintain current flow during “off” switching periods , thus enabling topographies where output voltage exceeds input voltage.
Do capacitors change voltage?
More generally, capacitors oppose changes in voltage —they tend to “want” their voltage to change “slowly”. – v i v = L di dt . An inductor’s current can’t change instantaneously, and inductors oppose changes in current.
Does current flow in a short circuit?
A short circuit implies that the two terminals are externally connected with resistance R=0 , the same as an ideal wire. ... This means that zero current can flow between the two terminals , regardless of any voltage difference.
Does magnetic field do any work?
The magnetic field does no work , so the kinetic energy and speed of a charged particle in a magnetic field remain constant. The magnetic force, acting perpendicular to the velocity of the particle, will cause circular motion.
How is energy stored in magnetic field?
The formula for the energy stored in a magnetic field is E = 1/2 LI 2 . The energy stored in a magnetic field is equal to the work needed to produce a current through the inductor. Energy is stored in a magnetic field. Energy density can be written as uB=B22μ u B = B 2 2 μ .
Does a uniform magnetic field do work?
Another way to look at this is that the magnetic force is always perpendicular to velocity, so that it does no work on the charged particle. The particle’s kinetic energy and speed thus remain constant. The direction of motion is affected but not the speed. ... The result is uniform circular motion.
