An electron with kinetic energy 1.40 kev circles in a plane perpendicular to a uniform magnetic field. the orbit radius is 30.0 cm. find (a) the speed of the electron, (no response) m/s (b) the magnetic field, (no response) t (c) the frequency of circling, and (no response) hz (d) the period of the motion.

(a)

(b)

(c)

(d)

Explanation:

Given:

Kinetic Energy of an electron,

radius of the orbit,

we have:

mass of an electron,

charge on an electron,

(a)

we know:

(b)

We also have the relation after the comparison of forces(centripetal and magnetic) on a moving charge in a magnetic field as:

...........................(1)

where:

B = magnetic field normal to the plane of circulating charge

putting respective values in eq. (1)

(d)

angular speed:

∴Time taken for 1 radian:

Now time take for 1 circulation i.e. 2π radians(Time period):

(c)

we know frequency :

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia

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