Lab 4 Parallel Plate Capacitor

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Introduction
Dielectric materials are insulators that make it harder for the electric field to penetrate the space within a capacitor; this is due to the theory of polarization. In Lab 4 (Parallel Plate Capacitor), the objective was to measure the dielectric constant (κ) of a textbook (paper) using a makeshift capacitor of aluminum foil. This was done through graphical analysis by the linearization of equation (1). The goal was to construct a linear graph in which the slope and slope error was calculated using the Linest function, the slope than allows for the derivation of the dielectric constant of the paper in a textbook. Error propagation (error formulas) was also used in this lab to account for sources of errors that could have occurred. …show more content…

In this equation C is the capacitance of the capacitor, κ is the dielectric constant of the insulating material, ε0 is the permittivity of free space, A is the area of the charged plate, and d is the dielectric thickness. This equation was rearranged to C = κε0A(1/d) as a linear line of y = mx + b, in which C = y, 1/d = x, and κε0A = slope(m).

(2) F = x/y = lFl x ((δx/IxI) + (δy/lyl)) was used for the error propagation of 1/d where x = 1 and y = d. This equation was also used for the error propagation of κ = slope/ ε0A where x = slope and y = A.

(3) F = xy = lFl x ((δx/IxI) + (δy/lyl)) = xδy + yδx was used for the error propagation of area where length = x and width = y to get the area of the parallel …show more content…

This suggests error in experimental procedure. Possible explanations for this error would be that air which has a dielectric constant of κ ≈ 1 still exists within the aluminum parallel plates; this will affect the calculations of κ to be a lower value such as the one in this experiment. Another explanation would be the difficulty in very small measurements. This experiment required the measurement of capacitance values around 10-12, and values this small show great error in precision, also the measurements of the page thickness and area of the parallel plate were very small. Also, he make-shift aluminum parallel plate capacitor is a lower quality instrument (non-professional) being used. This being said, paper is not a very good material for a commercial capacitor because it has a low dielectric constant. The dielectric constant of paper is still higher than air which means it is better than just air but it is small compared to other dielectrics with a higher dielectric constant. Larger dielectric constants are better because C ∝ κ as seen in equation (1), this means that the larger the dielectric constant, the greater stored charge for a given voltage because C = Q/V. Larger dielectric constants also prevent the conducting plates from coming into direct electrical contact. If the plates are not aligned properly, the area in calculations can only be the

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