This document discusses magnetic fields produced by solenoids. It defines a solenoid as a coil of wire that produces a strong magnetic field inside its core. The magnetic field strength inside a solenoid, B, is directly proportional to the number of turns N, and the current I, as described by the equation B=μNI. It also provides an example of writing a MATLAB program to plot the magnetic field in the x-z plane for a given solenoid geometry and current.

1. Submitted by :
Sec : 14
T.SAI SRAVANI(150040887)
U.RESHMI(150040900)
V.ANIL REDDY (150040921)

2. • A magnetic field is the magnetic effect of electric currents and magnetic materials.
• The magnetic field at any given point is specified by both a direction and
a magnitude (or strength) ; as such it is a Vector feild.
• Fields denoted by the symbols B and H :
• H is measured in units of amperes per meter (symbol: A·m−1 or A/m) in the SI.
• B is measured inTeslas (symbol:T). B is most commonly defined in terms of
the Lorentz force it exerts on moving electric charges.

3. • Magnetic fields are similar to electric fields, but they are
produced only by moving charges while electric fields are
produced by both moving charges and stationary charges.
• The direction the magnetic field produced by a moving charge is
perpendicular to the direction of motion.The direction of the
force due to a magnetic field is perpendicular to the direction of
motion.

4. • A solenoid is a coil of wire designed to create a strong magnetic field inside the coil. By
wrapping the same wire many times around a cylinder, the magnetic field due to the wires
can become quite strong.
• In a solenoid, the core material is ferromagnetic, meaning that it concentrates magnetic
lines of flux.This increases the inductance of the coil far beyond the inductance obtainable
with an air-core coil of the same dimensions and the same number of turns.

5. • Ampere’s law allows us to find the magnetic field on a closed loop that
surrounds a current.
• L – length of the coil, I = current in the coil , N=no.of turns in solenoid,
we have the equation for magnetic field as below and direction is
found through the right hand thumb rule. i.e
BL=µNI
B=µ(N/L)I
B=µnI

6. A solenoid of radius 0.1 m whose axis is the z axis carries a current of 3 Amps
wrapped in 1000 loops. The solenoid is assumed to extend along the z axis from
z = −0.5 m to z = 0.5 m. Write a MATLAB program that plots the magnetic field
in the x-z plane.

8. • When current flows in the coil, most of the resulting magnetic field exists within
the core material. Some flux appears outside the coil near the ends of the core; a
small amount of flux also appears outside the coil and off to the side.
• The number of turns N refers to the number of loops the solenoid has. More loops
will bring about a stronger magnetic field.

9. • Electromechanical solenoid
Electromechanical solenoids consist of an electromagnetically inductive coil,
wound around a movable steel or iron slug.
• Rotatory solenoid
The rotary solenoid is an electromechanical device used to rotate a ratcheting
mechanism when power is applied.
• Rotatory voice coil
Rotary voice coils are widely employed in devices such as disk drives.
• Pneumatic solenoid valve
This is a switch for routing air to any pneumatic device, usually an actuator.