please help answer the questions from 7-12 (the ones that I bolded). I am super
ID: 3307728 • Letter: P
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please help answer the questions from 7-12 (the ones that I bolded). I am super confused
Build an electroscope (device to check for the presence of electric charges in its vicinity) as shown in Fig. 1, by taping a straw onto the side of a Styrofoam cup and attaching a piece of tinsel to the end of the straw with some aluminum foil wrapped around the end. Ensure the tinsel is free to move about.
1. Build an electroscope (device to check for the presence of electric charges in its vicinity) as shown in Fig. 1, by taping a straw onto the side of a Styrofoam cup and attaching a piece of tinsel to the end of the straw with some aluminum foil wrapped around the end. Ensure the tinsel is free to move about.
2. Rub a styrofoam plate with fur or your hair. This gives the styrofoam plate a negative charge. Bring the plate toward (but not touching) the electroscope, approaching from the tinsel side. Repeat approaching from the opposite direction. (A) What happens in each case? (B) Why? (Explain using the rules above, in detail, using words and diagrams here and in other questions.) [Note: The electroscope might occasionally not return to its original state; in that case it will need to be discharged. Do this by putting it into contact with the (grounded) metal casing of an electrical outlet.]
3. Build the electrophorus as shown in Fig. 2, by taping the Styrofoam cup to the pie plate. [Electrophorus is a Greek-origin compound word literally meaning that which bears or produces (phorus) charge (electro).) To use it, rub the styrofoam plate with fur, and place the plate upside down on the table. Holding the coffee cup handle, place the aluminum pie plate on the charged styrofoam plate. If you watch closely, you will see that the styrofoam plate is attracted to the pie plate. (C) Why?
4. Without touching the metal, take the pie plate away and see if it is charged by using the electroscope. (D) Is it? [This is the single most important question; be sure you check your answer.] (E) Why or why not?
5. Place the pie plate on the styrofoam plate (again don’t touch the metal while placing it). Now touch the edge of the pie plate. You should hear a click. (F) What happened to produce this click?
6. Next, pick up the pie plate (via the handle) and bring pie plate near the electroscope as before. (G) Is it charged? (H) Why is this the case?
7. Now bring the pie plate in toward the electroscope from the side opposite the tinsel, touch the pie plate to the electroscope, and remove the pie plate. (J) What do you observe about the electroscope? (K) Why does this happen? Fig. 1. An electroscope. Fig. 2. An electrophorus.
8. Make a plume by tying three pieces of tinsel to a paper clip, as shown in Fig. 3. Attach the clip to the side of the pie plate. Discharge the pie plate by holding it in your hand and discharging yourself. Place it on the charged styrofoam plate as before, and charge it by touching the edge of it as before. (L) What happens to the plume as you remove the pie plate from the styrofoam? (M) Why does it do this?
9. Place the pie plate back on the styrofoam plate. (N) What happens to the plume? (O) Why?
10. Remove the pie plate again. The plume should again spread out. Now touch the metal pie plate. (P) What happens to the plume? (Q) Why?
11. Discharge the pie plate again, and place it on the charged electrophorus. Put a small ball of aluminum foil at the end of a thread and attach to a straw as shown in Fig. 4. Very slowly and carefully, bring the aluminum ball quite near the edge of the pie plate. (R) What happens? (S) Why?
12. Hold the straw so that the ball is about one centimeter from the edge of the pie plate as shown in Fig. 5. Bring your finger close to the aluminum ball. If done correctly, the aluminum ball will jump several (or very many!) times between the pie plate and your finger. (T) Why?
Plashic Fig. 1. Arn electroscope Fig. 2. An electrophorus.Explanation / Answer
7) By touching the electroscope from opposite side to the tinsel, the aluminium foil part of the electroscope gets charged.
j) So the tinsel gets attracted towards the foil. Touches it and moves away from it.
k) First, the foil is charged and the tinsel is not. So tinsels gets attracted and it touches the foil. After touching, the tinsel also acquires same charge as the foil so it repels.
8)
L) The tinsels move apart from each other.
M)As the plume is attached to the pie plate it has same charge as the pie plate which is positive. As all the tinsels are of positive charge, they repel and move apart.
9)
N) The plume gets attracted to the styrofoam plate.
O) This is because the styrofoam is - charged and the plume is + chrarged.
10)
p) The plumes just hang freely without attraction or repulsion.
Q) Upon touching the + charged pie plate, the electrons from our body flows into the pie plate thus discharging it.
11)
R) the foil ball touches the pie plate and then gets repelled.
S) the pie plate is + charged and the foil ball is neutral. So the ball gets attracted to the plate and touches it. then it gets the same charge as the pie plate and gets repelled.
12)
T) the pie plate has +ve charge and the finger is almost always neutral. So when the finger is brought close, the ball which is + after touching the pie plate gets attracted to the finger. Upon touchin the finger it gets discharged and is again attracted by the + pie plate. So this chraging and discharging cycle of the ball repeats.
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