Static Electricity review Flashcards
What are possible interactions between two charged objects?
- no attraction
- repulsion
- attraction
How does a charged object and neutral object interact?
they will attract
Explain the role of friction in creating a charged object
friction causes electrons to be come dislodged from one object and transferred to another object; this will cause one object to have a negative charge and the other positive
Would a negatively charged balloon stick to a metal wall as easily as to a wooden wall? Explain.
you want to check the electrostatic series; a larger distance between objects on the series will produce a stronger charge
wood and balloon (rubber) are closer than balloon and metal, therefore the balloon will more likely (easily stick to metal) than wood
You have an unknown material that becomes charged when you rub it with silk. You also have a negative ebonite rod and a positive glass rod. How can you determine the charge of the unknown object? how?
- if it is rubbed with silk, anything higher than it on the electrostatic series is positive, and anything below it is negative
- if it is attracted to ebonite (negative rod), then it must be positive
- if it is attracted to glass (positive rod), then it must be negative
- If lightning hits a car, the effect is minimal. Explain why.
- if it is attracted to ebonite (negative rod), then it must be positive
- if it is attracted to glass (positive rod), then it must be negative
A positively charged comb is brought near a negatively charged balloon. What will happen? Why?
- opposite charges attract; therefore the comb and balloon will attract one another
- How does a lightning rod prevent damage to a building hit by lightning?
a lightening rod provides grounding to the lightening
the rod (metal) is highly conductive and is put above the house/building so the lightening strikes it, directs the electricity (electrons) down it and into the ground to be distributed and neutralized
A cat rubs against a student’s rubber boot. The boot then touches the neutral pith ball of an electroscope. A piece of ebonite is brought near the pith ball electroscope, and the pith ball is observed to repel. What can you conclude about the type of charge on the ebonite? Explain
- If the cat (cat hair) rubs boot (rubber), the boot will have a negative charge (electrostatic series)
- When the boot touches the neutral pith ball, it transfers electrons to the pith ball (negative)
- If the ebonite rod repels, then it must be negative as well
Describe the difference between charging by friction and temporarily charging by induction
- Charging by friction – two neutral objects rub together and one transfers electrons to the other; one stays negative and the other is positive
- Charging by induction – two objects (one neutral, one charged) are brought close to each other, causing one (neutral) object to have a temporary positive or negative charge
. There are four pith balls. Pith ball #1 is repelled by pith ball #2. Pith ball #2 is attracted to pith ball #3 but repelled by pith ball #4. Pith ball #3 is attracted to pith ball #4. If pith ball #1 has a negative charge, what are the charges on pith balls #2, 3, & 4?
#1 – negative #2 - negative #3 – positive #4 - negative
. There are five pith balls. Ball # 3 attracts all other pith balls and is negative. Ball # 5 doesn’t repel # 1, #2 or #4. Balls # 1, #2 and #4 repel each other
#1 - positive #2 - positive #3 - negative #4 - positive #5 - neutral
. Which of these materials is the best insulator: aluminum, steel wool, salt water, glass
- An insulator is a poor conductor; glass is high on electrostatic series, rather be positive
What is static electricity?
It is a build up of charges
What is grounding?
“Grounding” an object means using a conductor to safely transfer electrons to the ground
