• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

charging a capacitor at a constant rate(C08)

Extracts from this document...

Introduction

School True Light Girls' College Mark Name Tam Teresa (???) Class (Class No.) 6S (22) /10 Group No. 3 Date (dd-mm-yy) 20-05-2009 ============================================================= AL Physics TAS - Experimental Worksheet C08 - Charging a capacitor at a constant rate Time Allowed 2 periods Objective To investigate how the charge on a capacitor is related to the potential difference applied across it by charging the capacitor at a constant rate. Apparatus * Capacitor (electrolytic type) 500�F * Microammeter 100�A * Potentiometer 100k? * Clip component holder * Stop-watch * CRO (Cathode Ray Oscillator) * Connecting leads Theory From definition, the capacitance C of a capacitor is found from C=Q/V where Q is the charge stored on the capacitor and V is the potential difference across it. ==> Q = CV ==> = C If a capacitor is charged up at a constant rate, i.e. = I , where I is a constant , then is also constant. Hence the potential difference across the capacitor increases linearly with time. Procedure 1. Connect up the circuit as shown in Fig. ...read more.

Middle

across the capacitor is directly proportional to time (V?t). Analysis For a constant current, the charge delivered to the capacitor is directly proportional to time. Q?t (Q = It) From the result of the experiment, the p.d. across the capacitor is directly proportional to time. V?t As a result, the charge delivered to the capacitor is directly proportional to the p.d. across it. Q?V Assumptions 1. The capacitor has been fully discharged before every charging. 2. The charging current is constant when the capacitor is charging. 3. The reading of times taken by the observer is exactly the same as the times for the p.d. across the capacitor to reach 1V, 2V, 3V, etc. Precautions of the experiment 1. A correct scale of ammeter should be chosen. The measured value of current may be out of range of ammeter if inappropriate ammeter is chosen. 2. As we use the stop-watch to take the times for the p.d. across the capacitor to reach 1V, 2V, 3V,etc, the reaction time of the observer plays large part. Therefore, we should have the same person for timing to prevent great time lag within same p.d. across capacitor. 3. ...read more.

Conclusion

across the capacitor to reach 1V, 2V, 3V, etc. 3. The capacitor may not fully discharged before charging, thus affect the results of times for the p.d. across the capacitor to reach 1V, 2V, 3V, etc. 4. It is too difficult to observe both stop-watch and reading of CRO trace. Thus, there may exist time lag and affects the results. Improvements 1. "Dry Runs" before actual measurement. 2. Use advance stop-watch which can take several readings at once. 3. Use video camera to capture the position of horizontal CRO trace against time. Thus, the reaction time of observer does not play a part in the experiment. The results of times are much more accurate. Limitations 1. The laboratory does not have advance stop-watch. 2. We do not have enough time to do several more times to take the average value of time to make the reaction time less significant. Comments This experiment has errors that make our experimental results inaccurate. Fortunately, I and my partner do cooperate well to minimize the error. Also, we conduct the experiment safely and the process is holistically fluent. Conclusion The charge on a capacitor is directly proportional to the potential difference applied across it by charging the capacitor at a constant rate. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Fields & Forces section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Fields & Forces essays

  1. Measuring The Constant g; The Acceleration Due To Gravity

    angle no higher than 30( from the normal, and then timing the period of four back and forth oscillations using the stopwatch, with maximum response time and alertness for pressing start and stop as the smallest deviations make a huge impact on the results.

  2. What Affects the Strength of Magnetism Exerted By an Electromagnet?

    The strength is defined as the range of the effective magnetic field and the concentration of the lines of flux emitted. However, the strength exerted will not be directly proportional to the coils of wire or the voltage. I believe that the magnetic strength emitted will be related to the voltage squared, as explained in my voltage theory.

  1. Investigating a factor affecting the voltage output of a transformer.

    in mind whilst carrying out my practical; * The power supply mustn't be on whilst I change the nominal voltage. * The power supply mustn't be switched on until the circuits are fully connected. * I will limit the size of the nominal voltage.

  2. Einstein's theory of relativity.

    It was believed to occupy the spaces between the atoms that made up matter. It offered no resistance to the earth's movement. Among the many experiments which helped destroy the ether theory, the most famous is that of Michelson and Morley in 1887.

  1. Investigating the Mechanics of the 100 Metre Sprint.

    abidzaman, please do not redistribute this hypothesis. We work very hard to create this website, and we trust our visitors to respect it for the good of other students. Please, do not circulate this hypothesis elsewhere on the internet. Anybody found doing so will be permanently banned.

  2. Aurora- Light of Mystery.

    everyday environment because most of the materials we encounter in everyday life are electrically neutral. In fact this field has been protecting the earth's atmosphere by stopping the solar wind in a magnetic shock wave. Without this magnetic field, the atmosphere will be exposed to the high-energy solar wind and the solar particles will strip the air of the earth.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work