1.
Properties of Photons
a.
Applying Einstein's mass  energy equation
E = mc^{2}
Where E = energy,
m = mass,
c = velocity of light.
Mass of a photon is obtained as follows:
m=

E

=

hn

=

h




C^{2}

C^{2}

C l

b.
c.
Momentum of a photon is given by,
p = mc

E

.c
=

hv

=

h




C^{2}

C^{2}

C l

d.
e.
Energy of a photon = hv;
energy of a beam of n photons = nhv.
f.
Photons are electrically neutral.
2.
Path of a Charged Particle in a Magnetic Field
A charged particle moving with velocity

n

in a magnetic field

B

experiences a force

3.
a.
If a charged particle moving with velocity enters
a uniform magnetic field perpendicular to its velocity, it moves in a
circular path of radius
r =

mn


qB

b.
where m

= mass of the particle,

q

= charge on the particle.

c.
d.
If a charged particle enters a uniform magnetic field so that
its velocity makes an angle q with the field (i.e., its velocity has a component in the
direction of the field), then it moves in hellical
path around the direction of the field.
e.
If a charged particle enters a uniform magnetic field directed
parallel to its velocity, then it experiences no force and continues to
travel undeflected in a straight line.
