Answer Happy

Lab: Electrostatics PHY 221 B. Now imagine repeating this experim nagine repeating this experiment with the knife touching the top of the electroscope, as shown. Treating the electroscope and knife as Top of electroscope a single object, would you expect Foil-covered them (collectively) to have a net Charged rod knife charge that is positive, negative, or zero? Collectively, they have a net charce of 20ro On the diagram, sketch how the charges are distributed on the electroscope and knife while the charged rod is held near. WALA Finally, suppose that the knife was carefully moved away from the electroscope, and then the charged rod was removed. Do you think that the electroscope would now be charged? If so, what would be the sign of the net charge? Explain. C. Here you will test your answers in part B experimentally, except that you will use your finger in place of the foil-covered knife, as described below. Finger First, touch the ball of the electroscope with your finger, then bring a charged rod near (but not touching the electroscope). Carefully remove your finger first, then remove the charged rod. Charged rod (Note: If you observe "sparking" at any time, repeat the process from the beginning.) Top of electroscope 1. The electroscope should now be charged. How can you tell whether or not it is, in fact, charged? 2. Predict whether the sign of the net charge on the electroscope is positive, negative, or zero. Explain your reasoning. To support your prediction, use the diagram above to show how the charges are distributed on the electroscope and on your finger.