View Single Post
Genericcoder
#1
Feb27-12, 03:42 AM
P: 131
Hi guys I am learning about electrostatic on my own and was solving some problems but I am having problems with these questions please help.

An electron is released within a uniform electric field of a magnitude of 28,000 N/C generated by two parallel plates. The plates are separated by 4 cm. If the electron has moved across the entire gap between the plates, what is its speed?

We can get the force of the Particale in such electric field
which will be
F = 28 * 10^3 * - 1.6 * 10^-19;
F = -4.48 * 10^-15;

We know here it will follow a parabolic path so I have stopped from here I don't know where to start to solve this problem.

How much work is required to bring a 10.0 μC charge from infinity to 5.00 meters away from a point charge of -2.00 μC?

I solved this problem but can't find the answer on the given choices,since they don't provide answer here is how I tried to solve for it. I want to know if my answer is correct.

I reasoned through this as follows I assumed the charge is already 10 charge is 5 meters away,since the potential from infinity is zero and this would approximate result.
So I got the force that they were putting on each other distance 5 meters away as:

F = 9 * 10^9 * 10 * 10^-6 * -2 * 10^-6 / 5^2 = -7.2 * 10^-3;
So work done should be w = -7.2 * 10^-3 * 5 = -0.036J;
W = -3.6 * 10^-2

The answer exists in the multiple choice but I don't know if its correct please let me know if it is.


An electron moves 0.10 m along the direction of an electric field of a magnitude of 3.0 N/C. What is the potential difference between the electron’s initial and final points?

a. 4.8 x 10–20 V
b. 1.6 x 10–20 J
c. –4.8 x 10–20 J
d. –1.6 x 10–20 J

I don't know where to start to solve this problem.

Thanks for help in advance.
Phys.Org News Partner Science news on Phys.org
'Office life' of bacteria may be their weak spot
Lunar explorers will walk at higher speeds than thought
Philips introduces BlueTouch, PulseRelief control for pain relief