/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 11 What is the speed of a proton th... [FREE SOLUTION] | 91Ó°ÊÓ

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What is the speed of a proton that has been accelerated from rest through a potential difference of -1000 V?

Short Answer

Expert verified
The speed of the proton is approximately \(4.39 * 10^6 m/s\). Note, the negative potential difference implies that proton is moving against the electric field.

Step by step solution

01

Calculate the energy of the proton

The energy \(E\) of the proton can be calculated by using the equation \(E = qV\), where \(q\) is the charge of the proton \(1.602 * 10^{-19} C\) and \(V\) is the potential difference. Here V = -1000V. Hence, \(E = 1.602 * 10^{-19} C * (-1000V) = -1.602 * 10^{-16} Joules\).
02

Use the conservation of energy principle

By the conservation of energy principle, this energy is converted completely into kinetic energy, by the equation \(E = \frac{1}{2} mv^2\), where \(m\) is the mass of the proton \(1.6726219 * 10^{-27} kg\) and \(v\) is its velocity. Given that E is negative, we can conclude that the proton moves in the opposite direction to the electric field.
03

Determine the speed of the proton

Rearranging the kinetic energy equation for v gives: \(v= \sqrt {\frac{2E}{m}} \). Hence, \(v = \sqrt {\frac{ -2(-1.602 * 10^{-16} Joules)}{1.6726219 * 10^{-27} kg}}\), which leads us to determine the absolute value of speed \(v\).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Electric Potential Difference
Electric potential difference, also known as voltage, is a fundamental concept in physics. It's defined as the work done per unit charge to move a small, positive test charge between two points without producing an acceleration. When dealing with the speed of a charged particle, like a proton, being accelerated by an electric potential difference, we're typically talking about converting electric potential energy into kinetic energy. In the given problem, a proton is accelerated through a potential difference of -1000 V, meaning it gains energy as it moves from a higher to a lower electric potential area.

Understanding this concept is key because the magnitude of this potential difference determines how much kinetic energy the proton will have once it is fully accelerated. It is also important to note that the negative sign indicates the direction of acceleration relative to the direction of the electric field.
Electric Charge
Electric charge is a property of particles that causes them to experience a force when placed in an electric and magnetic field. There are two types of electric charge: positive and negative. Like charges repel each other, while opposite charges attract. The concept is vital in our problem because the proton has a positive electric charge, specifically, it carries a charge of approximately 1.602 x 10^-19 coulombs (C).

This electric charge is what interacts with the electric field created by the potential difference; it's the reason why the proton accelerates. When we calculate the energy gained by the proton in the electric field, the charge plays a monumental role in determining the amount of energy imparted to the proton.
Conservation of Energy Principle
The conservation of energy principle is a cornerstone of physics stating that energy cannot be created or destroyed, only transformed from one form to another. In the context of our proton's journey, it implies that the electric potential energy, initially due to the proton's position in an electric field, is converted into kinetic energy as the proton accelerates.

Using this principle in the step-by-step solution, we see that the initial energy of the proton, which is electric potential energy given by the product of its charge and the potential difference, is entirely transformed into kinetic energy. The conservation of energy allows us to set up an equation linking the potential energy (before the acceleration) to the kinetic energy (after the acceleration), helping us find the proton's final speed.
Kinetic Energy
Kinetic energy is the energy an object possesses due to its motion. It depends on two variables: the mass of the object and the square of its velocity. Mathematically, it's expressed as \(KE = \frac{1}{2} mv^2\), where \(m\) is mass and \(v\) is velocity. When we apply this concept to the accelerating proton, we equate the energy from the electric potential difference to this formula to solve for the proton's velocity.

In this scenario, the kinetic energy acquired by the proton must account for the change in electric potential energy. Once we know the kinetic energy, we can solve for the velocity by rearranging the kinetic energy equation. This results in the speed of the proton being directly related to the square root of its kinetic energy divided by its mass.
Proton Mass
The proton mass is an intrinsic property of protons, which are subatomic particles found in the nucleus of every atom. The mass of a proton is crucial in calculations involving the movement and acceleration of protons in fields, such as our problem. The proton's mass is quite small, approximately 1.6726219 x 10^-27 kilograms.

The mass is significant in the solution to our problem; it's necessary for calculating the kinetic energy and, subsequently, the speed of the proton after it's been accelerated by the electric potential difference. Given that more massive particles require more energy to achieve the same speed as less massive particles, the specific mass of the proton helps us find the precise speed increment resulting from the given energy change.

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Most popular questions from this chapter

A hollow cylindrical shell of length \(L\) and radius \(R\) has charge \(Q\) uniformly distributed along its length. What is the electric potential at the center of the cylinder?

A proton and an alpha particle \((q=+2 e, m=4\) u) are fired directly toward each other from far away, each with an initial speed of \(0.010 c .\) What is their distance of closest approach, as measured between their centers?

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A \(20 \mathrm{cm} \times 2.0 \mathrm{cm}\) parallel-plate capacitor has a \(2.0 \mathrm{mm}\) spacing. The electric field strength inside the capacitor is \(10 \times 10^{5} \mathrm{V} / \mathrm{m}\) a. What is the potential difference across the capacitor? b. How much charge is on each plate?

A water molecule perpendicular to an electric field has \(1.0 \times\) \(10^{-21} \mathrm{J}\) more potential energy than a water molecule aligned with the field. The dipole moment of a water molecule is \(6.2 \times 10^{-30} \mathrm{C} \mathrm{m} .\) What is the strength of the electric field?

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