Physics, 12.03.2020 02:33 gg68814

An electron is released from rest at the negative plate of a parallel plate capacitor. The charge per unit area on each plate is = 2.5 x 10⁻⁷ C/m², and the plates are separated by a distance of 1.7 x 10⁻² m. How fast is the electron moving just before it reaches the positive plate?

Answers: 2

Show answers

Answers

Answer from: liluv8262

The speed of the electron before reaching the positive plate is $1.30 \times 10^{7}\ m / s$

Explanation:

As per Gauss law of electro statistics, the electric field generated by a capacitor is directly proportional to the surface charge density of the plate and inversely proportional to the dielectric constant. In simple words, the electric field is proportional to the surface charge density. So,

$\text {Electric field}=\frac{\sigma}{\varepsilon_{0}}$

And then from the second law of motion, $F=m \times acceleration$

So acceleration exerted by the electrons will be directly proportional to the force exerted on them and inversely proportional to the mass of the electron.

$Acceleration =\frac{F}{m}$

Since force is also calculated as product of charge with electric field in electrostatic force,

$\text {Acceleration}=\frac{q E}{m}=\frac{q \sigma}{m \varepsilon_{0}}$

So, the charge of electron $q=1.6 \times 10^{-19}\ \mathrm{C}, \sigma=\text { Charge per unit area }=2.5 \times 10^{-7}\ \mathrm{C} / \mathrm{m}^{2}$

m is the mass of electron which is equal to $9.11 \times 10^{-31}\ \mathrm{kg}$

$\varepsilon_{0}=8.85 \times 10^{-12}\ \mathrm{Nm}^{2} \mathrm{C}^{-2}$

Then,

$\text { Acceleration }=\frac{1.6 \times 2.5 \times 10^{-19} \times 10^{-7}}{9.11 \times 8.85 \times 10^{-31} \times 10^{-12}}=\frac{4 \times 10^{-19-7}}{80.62 \times 10^{-31-12}}$

$\text { Acceleration }=0.0496 \times 10^{-19-7+31+12}=0.0496 \times 10^{17}\ \mathrm{m} / \mathrm{s}^{2}$

So the acceleration of the electron in the capacitor will be $4.96 \times 10^{15} m / s^{2}$

Then, the velocity can be observed from the third equation of motion.

$v^{2}=u^{2}+2 a s$

As u = 0 and s is the distance of separation between two plates.

$\begin{array}{c}v^{2}=0+\left(2 \times 4.96 \times 10^{15} \times 1.7 * 10^{-2}\right) \\v^{2}=16.864 \times 10^{15-2}=16.864 \times 10^{13}=1.684 \times 10^{14}\end{array}$

Thus, $v=\sqrt{\left(1.68 \times 10^{14}\right)}=1.30 \times 10^{7}\ m/s$

So, the speed of the electron before reaching the positive plate is $1.30 \times 10^{7} \mathrm{m} / \mathrm{s}$ .

Answer from: Quest

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol

b. a hockey puck sliding across the ice

c. a compressed spring

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice is the correct option.

Answer from: Quest

the moving of the box is a result of centripetal force. think of that as a car or a truck in this case creates a turn, the force of friction performing upon the turned wheels of the car runs centripetal force obligatory for circular motion for the things inside it.

Another question on Physics

Physics, 22.06.2019 05:40

Karen is running forward at a speed of 9 m/s. she tosses her sweaty headband backward at a speed of 20 m/s. the speed of the headband, to the nearest whole number relative to a stationary observer watching karen

Answers: 1

Answer

Physics, 22.06.2019 10:10

Aclarinetist, setting out for a performance, grabs his 3.350 kg clarinet case (including the clarinet) from the top of the piano and carries it through the air with an upward force of 24.65 n. find the case's vertical acceleration. indicate an upward acceleration as positive and a downward one as negative.

Answers: 1

Answer

Physics, 22.06.2019 11:40

Consider the following position function. find (a) the velocity and the speed of the object and (b) the acceleration of the object. bold r left parenthesis t right parenthesisr(t)equals=left angle 6 t superscript 4 baseline comma 2 t cubed right angle6t4,2t3 for tgreater than or equals≥0

Answers: 3

Answer

Physics, 22.06.2019 14:00

Often called simply "velocity," this is the velocity of an object at a particular moment in time.

Answers: 1

Answer

You know the right answer?

An electron is released from rest at the negative plate of a parallel plate capacitor. The charge pe...

Questions