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Ch 26: Potential and Field
Knight Calc - Physics for Scientists and Engineers 5th Edition
Knight Calc5th EditionPhysics for Scientists and EngineersISBN: 9780137344796Not the one you use?Change textbook
Chapter 26, Problem 15

The electric potential along the x-axis is V = 100x2 V, where x is in meters. What is Ex at (a) x=0 m and (b) x=1 m?

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Step 1: Recall the relationship between electric potential (V) and electric field (E). The electric field is the negative gradient of the electric potential. Mathematically, this is expressed as: E_x = -dV/dx, where E_x is the electric field along the x-axis and V is the electric potential.
Step 2: Differentiate the given electric potential function V = 100x^2 with respect to x. The derivative is: dV/dx = 200x.
Step 3: Substitute the value of x = 0 into the expression for E_x. Using E_x = -dV/dx, calculate E_x at x = 0.
Step 4: Similarly, substitute the value of x = 1 into the expression for E_x. Using E_x = -dV/dx, calculate E_x at x = 1.
Step 5: Interpret the results. Note that the electric field is a vector quantity, and its direction is determined by the negative gradient of the potential. Discuss how the values of E_x at x = 0 and x = 1 relate to the behavior of the electric field along the x-axis.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Electric Potential

Electric potential, denoted as V, is the amount of electric potential energy per unit charge at a point in an electric field. It is a scalar quantity measured in volts (V) and indicates how much work would be done to move a charge from a reference point to a specific point in the field without any acceleration.
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Electric Field

The electric field (E) is a vector field that represents the force experienced by a unit positive charge placed in the field. It is defined as the negative gradient of the electric potential, mathematically expressed as E = -dV/dx. This relationship shows how the electric field is related to the spatial change in electric potential.
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Gradient

In physics, the gradient is a vector that represents the rate and direction of change in a scalar field. For electric potential, the gradient indicates how the potential changes with respect to position. In this context, calculating the gradient of the potential function V = 100x^2 allows us to determine the electric field at specific points along the x-axis.