# PHYSICS

An alpha particle (which has two protons) is sent directly toward a target nucleus containing 80 protons. The alpha particle has an initial kinetic energy of 0.79 pJ. What is the least center-to-center distance the alpha particle will be from the target nucleus, assuming the nucleus does not move? The charge of a proton is 1.602 x 10-19 C.

1. 👍 0
2. 👎 0
3. 👁 274
1. The potential energy due to the Coulomb replsion force is
-k Q1 Q2/R
at separation distance.
k is the Coulomb constant and Q1 and Q2 are the two positive nuclear charges. When the nuclei are at closest separation distance d, the relative velocity is zero. You can ignore the effect of the 80 electrons around the larger nucleus.

Initial kinetic energy = potential energy change
0.79*10^-12 J = k Q1 Q2/d = 2*80 k e^2/d

Solve for d

1. 👍 0
2. 👎 0
posted by drwls
2. He has the right equation, but the wrong exponents.

Equation = (r = (KQ)/K0)

K = 9 * 10^9
Q = (2*e*#protons*e)
K0 = initial ke * 10^-12

Example:
(K*(2*1.602E-19*86*1.602E-19))/.39E-12
= 1.017E-13m

1. 👍 0
2. 👎 0
posted by Caleb

## Similar Questions

1. ### Chemistry

Why is an alpha particle written as a helium (He) nucleus? A. An alpha particle has two protons and two neutrons; it is essentially the nucleus of a helium atom. B. Helium is a common element that is often present in small forms;

asked by Michael on January 26, 2018
2. ### Physics

In 1910 Rutherford performed a classic experiment in which he directed a beam of alpha particles at a thin gold foil. He unexpectedly observed a few of the particles scattered almost directly backward. This result was not

asked by Brandi on July 2, 2014
3. ### physics

In Rutherford's famous scattering experiments that led to the planetary model of the atom, alpha particles (having charges of +2e and masses of 6.64 10-27 kg) were fired toward a gold nucleus with charge +79e. An alpha particle,

asked by Mike on October 14, 2010
4. ### physics

In Rutherford's famous scattering experiments that led to the planetary model of the atom, alpha particles (having charges of +2e and masses of 6.64 × 10−27 kg) were fired toward a gold nucleus with charge +79e. An alpha

asked by Sara on January 23, 2013
5. ### Physics

In a location in outer space far from all other objects, a nucleus whose mass is 3.57232e-25 kg and which is initially at rest undergoes spontaneous "alpha" decay. The original nucleus disappears, and two new particles appear: a

asked by bryce tanaka on October 7, 2011
6. ### physics

An atomic nucleus at rest decays radioactively into an alpha particle and a nucleus smaller than the original. What will be the speed of this recoiling nucleus if the speed of the alpha particle is 1.20E+05 m/s? Assume the

asked by kassy on October 25, 2016
7. ### Physics

An atomic nucleus at rest decays radioactively into an alpha particle and a nucleus smaller than the original. What will be the speed of this recoiling nucleus if the speed of the alpha particle is 2.20E+05 m/s? Assume the

asked by Victoria on April 10, 2015
8. ### Chemistry

What is the maximum velocity (in m/s) acquired by an alpha particle when accelerated between two plates with a potential difference of 580.0 volts? Note: An alpha particle is essentially the nucleus of a helium atom - 2 protons

asked by Stephanie on October 18, 2014
9. ### Physics help!

An alpha particle(charge +2e) is sent at a speed towards a gold nucleus( +79e ). 1) what is the electric force acting on the alpha particle when it is 2.0 x 10^-14 m from the gold nucleus. 2) if the alpha particle came to a stop

asked by Happiness delight on August 14, 2017
10. ### Physics

The nucleus of 8Be, which consists of 4 protons and 4 neutrons, is very unstable and spontaneously breaks into two alpha particles (helium nuclei, each consisting of 2 protons and 2 neutrons). (a) What is the force between the two

asked by Sonam on March 14, 2009

More Similar Questions