To find electric field strength, bring in it the known trial charge. Measure force which affects it from the field and calculate value of tension. If electric field is created by a dot charge or the condenser, calculate it by special formulas.
It is required to you
- electrometer, dynamometer, voltmeter, ruler and protractor.
Instruction
1. Definition of tension of any electric field Take a charged body which sizes are insignificant in comparison by the sizes of the body generating electric field. Well the loaded metal ball with a small weight will approach. Measure the size of its charge by the electrometer and bring in electric field. Counterbalance force operating on a charge from electric field with a dynamometer and take readings from it in newtons. After that value of force, divide into charge size in Pendants (E=F/q). The electric field strength in volts on meter will be result.
2. Determination of strength of electric field of a dot charge If electric field is generated by a charge which size is known, for definition of his tension in some point of space remote from it, measure this distance between the chosen point and a charge in meters. After that charge size in Pendants, divide into the measured distance built in the second degree (q/r²). Increase the received result by coefficient 9*10^9.
3. Determination of strength of electric field of the condenser Measure potential difference (tension) between condenser plates. For this purpose parallel to them attach the voltmeter, record result in volts. Then measure distance between these plates in meters. Divide value of tension into distance between plates, the electric field strength will be result. If not air is located between plates, define dielectric permeability of this environment and divide result not its value.
4. Definition of the electric field created by several fields If the field in this point is result of imposing of several electric fields, find the vector sum of values of this field, taking into account their direction (principle of superposition of fields). If it is necessary to find the electric field formed by two fields construct their vectors in this point, measure a corner between them. Then square each of their values, find their sum. Calculate the work of values of tension of fields, increase it by a cosine of the angle which is equal 180º minus a corner between vectors of tensions, and increase result by 2. After that from the sum of squares of tensions take away the received number (E=E1²+E2²-2E1E2*Cos(180º-α)). At creation of fields consider that power lines leave positive charges and are included into negative.