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Question

An electron and a proton are each placed at rest in an external electric field of 520 N/C. Calculate the speed of each particle after 48 NS

Answer 1

if the electron and the proton are not interacting then then the motion of each particle is uniformly accelerated and

acceleration=force/mass=chargexelectri... field/mass

speed of the particle=accelerationxtime=chargexelectr... (1)

look for the charge and the mass of electron and introduce the corresponding values in (1)

Answer 2

Easy... Force = electric field strength * charge

hence for the proton and neutron, Force = 520 * 1.6E-19 = 8.32E-17 newtons.

Accel = Force/mass

for the electron: accel = 8.32E-17 / 9.11E-31= 9.13E+13 m/s^2

for the proton accel = 8.32E-17 / 1.67 E-27 = 5.00E+10 m/s^2

Final speed: v = u+at (letters have their usual meanings. u=0 because the particles started at rest)

For the electron: v = 9.13E+13 * 48E-9 = 43,824,000 m/s

For the proton : v = 5.00E+10 * 48E-9 = 2400m/s

There you go. I used standard values for mass and charge of protons and electrons. The capital E means "exponent" and is a shorthand for writing ...x 10 ^...

Answer 3

This problem requires a few steps:

1.  Find the force,

2.  Find the acceleration,

3.  Find the speed.

For force,

F = q*E, where

F = force in N

q = charge in Coulombs

E = electric field in N/C

Both electron and proton have a charge of 1.6e-19C, so they have the same force on them:

F = q*E = 1.6e-19C * 520N/C = 8.32e-17N

Now the acceleration:

F = m*a, where

m = mass in kg

a = acceleration in m/s^2

Solving for a:

a = F/m

The mass of an electron is 9.1e-31kg, the proton mass is 1.67e-27kg.  The acceleration of the electron will be ~1800 times higher than that of the proton, to check your answer.

Now that you have the accelerations, use the motion formula:

v = a*t, where

v = velocity in m/s

a = acceleration in m/s^2

t = time in seconds.

And remember, 48ns = 48e-9 s!