The demonstration electroscopes used at lectures on physics have conditional graduation. At implementation of calculations it is necessary to know the value of a charge on the electroscope expressed in pendants. To transfer a charge on the electroscope to pendants, it is necessary to calculate special coefficient in the beginning.
It is required to you
- Electrometer, electroscope, microampermeter, mobile phone.
Instruction
1. Take the most sensitive magnetoelectric microampermeter what you have (for example, on 30 microamperes). Turn on it between an exit of a source of high voltage (in several kilovolt and it is obligatory with restriction of current to 0.1 ma) and the entrance terminal of the electroscope in such polarity that the terminal attached to a source had the same sign, as polarity of tension developed by a source.
2. Ask the assistant who is at safe distance from devices to film the events by means of the mobile phone. On video indications of the microampermeter have to be looked through accurately (indications of the electroscope after the termination of charging will remain invariable).
3. Include a source of high voltage, wait until his shooter deviates exactly to one of divisions then disconnect a source. Remember on what division the arrow stopped then a zamykatel with well isolated handle discharge the electroscope. Now installation can be investigated.
4. Track on video what current showed the microampermeter. Using time counter which is built in the player, calculate how many seconds the source was included. Transfer current from microamperes to amperes, having divided indications of the microampermeter into one million.
5. One pendant represents the charge corresponding to passing of current to one ampere within one second. So that to learn an electrometer charge, divide the current shown microampermeters (transferred to amperes) into the electrometer charging duration expressed in seconds. Very small number will turn out therefore it should be transferred to more convenient units (depending on the electrometer sizes, it can be millikulona, micropendants or pikokulona).
6. Divide an electroscope charge into the number of divisions on which the arrow after the end of experience deviated. So you learn the price of division of the electrometer.
7. Sometimes there is a task to learn the sign of a charge on the electrometer. For this purpose manufacture adaptation with the isolated handle, similar to a zamykatel, but consisting of a neon lamp and the resistor on several megaohm. Discharge the electrometer on this device - to that electrode of a neon lamp which at the same time will be lit, there corresponds the negative pole.