The magnetic field lines follow the longitudinal path of the solenoid inside, so they must go in the opposite direction outside of the solenoid so that the lines can form a loop. ... In order for the total number of field lines to be conserved, the field outside must go to zero as the solenoid gets longer .
Why is B zero outside a solenoid?
Because although the magnetic field is stronger inside the solenoid (because the shape of the solenoid reinforces it) the current flowing through the coil generates a magnetic field outside too and it is not cancelled completely, thus B is non-zero outside the solenoid.
Why magnetic field outside an ideal solenoid is zero?
The magnetic field lines exist outside the solenoid, but the number of field lines per unit area outside the solenoid is much less compared to the number of lines per unit area inside the solenoid. Hence the magnetic field outside is so feeble that it is considered to be practically zero.
Why magnetic field outside a toroid is zero?
You will observe that current that flows at outer circumference and inner circumference of toroid are in opposite direction to each other. Therefore, current enclosed by Amperian loop is zero . Thus, magnetic field outside the toroid is zero.
Is magnetic field outside a long solenoid is zero?
Note: For a very long solenoid the magnetic field outside will be zero and magnetic will be present only inside the solenoid.
How do you calculate the magnetic field outside a solenoid?
Outside the solenoid, the magnetic field is zero. n=300turns0.140m= 2.14×103turns/m .
Where the magnetic field of a solenoid is strongest?
The magnetic field is strongest inside the coil of a solenoid.
Is magnetic field inside a solenoid is zero?
magnetic field inside a solenoid is uniform as the lines move from north to south in a uniform manner with same magnitude without giving any diflection except for the fact that magnetic fields are stronger near the poles.
Is solenoid a permanent magnet?
1. A solenoid is a temporary magnet as it can readily be demagnetized by stopping the current through the solenoid whereas a bar magnet which is a permanent magnet cannot be demagnetized.
Why does a solenoid have a magnetic field?
Solenoids. A solenoid is a long coil of wire. When a direct electric current is passed through it, the shape of the magnetic field is very similar to the field of a bar magnet. ... The small magnetic fields caused by the current in each turn of the coil add together to make a stronger overall magnetic field .
Is there magnetic field outside a toroid?
It is easy to show, by using Amperian loops that are either smaller or bigger than the toroid, that the magnetic field everywhere outside of the toroid is exactly zero (as those Amperian loops will enclose no net current). In a toroid, the magnetic field lines form closed circles.
Where is toroid used?
Toroidal inductors and transformers are used in a wide range of electronic circuits : power supplies, inverters, and amplifiers, which in turn are used in the vast majority of electrical equipment: TVs, radios, computers, and audio systems.
What is the magnetic field inside a toroid?
The magnetic field in the open space inside (point P) and exterior to the toroid (point Q) is zero . The field B inside the toroid is constant in magnitude for the ideal toroid of closely wound turns.
What is the magnetic field outside the ideal solenoid?
It is well known that the longitudinal magnetic field outside an ideal solenoid (i.e., one that is wound infinitely tightly and that is infinitely long) is zero .
What happens to the magnetic field in the solenoid when the number of turns increases 1 point?
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 is the magnetic field inside a solenoid?
Inside a solenoid the magnetic field lines will be straight lines and the field will be strong. Outside the solenoid the magnetic field will be weak and the field lines will curl up to form closed loops. Hence, the magnetic field inside a solenoid will be uniform .
