(In fact, the electromagnetic force is found to be one of just four fundamental forces, the others being gravity, the strong nuclear force, and the weak nuclear force.) Quantum mechanics also facilitates greater insight into the nature of electric charge and of the photon, which is the fundamental constituent of electromagnetic waves. However, a deeper understanding is possible using quantum mechanics, where we find that the electric field and the magnetic field are in fact manifestations of the same fundamental force, aptly named the electromagnetic force. This is the best we can do using classical physics, and fortunately, this is completely adequate for the most engineering applications. We have have not directly addressed the question of what the electric field is.
The electric field intensity at any point is the strength of. The reader may have noticed that we have defined the electric field in terms of what it does. It is defined at any point as the force experienced by unit positive charge placed at that point. This is very clear as positive charge will repel the test charge.\( \newcommand\) is the rate of change in electric potential with distance in this direction. If you find the direction of electric field intensity at different points and plot it, you will notice that it is radially outward and emanating from the charge. The magnitude and direction of the electric field are expressed by the value of E, called electric field strength or electric field intensity or simply the. A uniform electric field is an ideal case in which the electric field lines are parallel with one another, for example between the plates of a large, parallel plate air capacitor. Electric Lines of Forces due to a Point ChargeĮlectric Field due to a single point positive charge can easily be calculated at different points in the space using Columb’s Law and the method explained. The electric field intensity (volts/meter) at any location is the force (Newtons) that would be experienced by unit test charge (Coulombs) placed at the location. It is also know as electric lines of forces.To draw electric field lines, we find the direction of electric field intensity vector at different points around the charge and make a plot. Electric Field lines are nothing but the graphical representation of electric field due to a charge in the space.
ELECTRIC FIELD INTENSITY HOW TO
We now know how to find the direction of electric field intensity vector at a particular point. Electric Field Lines and their Significance Thus the electric field intensity vector at point D has a magnitude of Q / (4πξa 2) and direction as shown in figure above. Net force on unit test charge at point D = R + F DB Now, resultant vector R and F DB are along the same along the same line making an angle of 45 degree from origin. R will beį DA + F DC = R = 2FCos(90/2) at an angle of 45°. Hence, here the resultant of F DA and F DC i.e. The direction of this resultant vector is at an angle of Ɵ/2 from either of the vector. We know that, resultant of two equal vectors at an angle Ɵ is 2FCos(Ɵ/2). Since F DA = F DC = Q / (4πξa 2) = F (say)
Now, we need to find the resultant of F DA, F DB and F DC. Step2: Find the resultant force on unit test charge.įorce on test charge at D due to charge at A, F DA = Q / (4πξa 2)įorce on test charge at D due to charge at C, F DC = Q / (4πξa 2)įorce on test charge at D due to charge at B, F DB = Q / (4πξ(√2a) 2) Step 1: Keep a unit test charge at point D. Let’s first draw the figure as shown below. Find the electric field intensity vector at fourth corner. The magnitude of resultant force is the Electric Field Intensity at that point and the direction of resultant force gives the direction of Electric Field Intensity at that point.Įxample: Four charges of equal magnitude +Q are kept at the three corners of a square of side ‘a’.Mind here that, if there are more than one charge then you need to find the resultant of individual forces.
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