Need Help On Electrical Potential Energy

[bongopukerat]

I need help on these ?'s. They are very confusing to me. Can someone please help me.
-Here they are:

>Two charges are located along the x-axis. ONe has a charge of 6.4 micro C, and the second has a charge of -3.2 micro C. If the electrical potential energy associated with the pair of charges is -4.1x10 to the -2 J, what is the distance between the charges?

>A charge moves a distance of 2.0 cm in the direction of a uniform electric field having a magnitude of 215 N/C. The electrical potential energy of the charge decreases by 6.9x10 to the -19 J as it moves. Find the magnitude of the charge on the moving particle. (Hint: The electrical potential energy depends on the distance moved in the direction of the field.)

>Two alpha particles (helium Nuclei), each consisting of two protons and two neutrons, have and electrical potential energy of 6.32x10 to the -19 J. What is the distance between these particles at this time?

Thanks!

 

[Sirus]

I'm assuming this is homework and you aren't just doing these for fun, so we need to see you attempt the problems first.

 

[Graeme Robinson]

Electrical potential energy is a concept that can be difficult to understand at first, but with some practice and explanation, it can become clearer. Let's go through each question one by one and try to break down the concepts involved.

1. In the first question, we are given two charges located along the x-axis. One charge has a positive value of 6.4 micro C and the other has a negative value of -3.2 micro C. The electrical potential energy associated with these charges is given as -4.1x10 to the -2 J. This value is negative, which means that there is a net attraction between the charges. The question asks us to find the distance between the charges.

To solve this problem, we can use the formula for electrical potential energy, which is U = kQ1Q2/r, where k is the Coulomb's constant, Q1 and Q2 are the charges, and r is the distance between them. We can rearrange this formula to solve for r: r = kQ1Q2/U. Plugging in the values given in the question, we get r = (9x10^9)(6.4x10^-6)(3.2x10^-6)/(-4.1x10^-2) = 2.46 m.

2. In the second question, we are given a charge that moves a distance of 2.0 cm in the direction of a uniform electric field with a magnitude of 215 N/C. The electrical potential energy of the charge decreases by 6.9x10 to the -19 J as it moves. We are asked to find the magnitude of the charge on the moving particle.

To solve this problem, we need to use the formula for electrical potential energy again, but this time we are solving for the charge Q. The formula is U = QEd, where E is the electric field strength and d is the distance moved in the direction of the field. Rearranging this formula, we get Q = U/Ed. Plugging in the values given in the question, we get Q = (6.9x10^-19)/(215)(0.02) = 1.6x10^-21 C.

3. In the third question, we are given two alpha particles with an electrical potential energy of 6.32x10 to the -19 J. We are asked to find the distance between the particles.