Force between charged and uncharged objects:
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Ellie rubs a polythene rod on a woollen cloth.
The rod gains a negative charge and the cloth get positively charged.
She scatters some tiny pieces of paper on a bench.
First, she brings the rod next to the paper pieces.
The paper pieces are attracted to the rod.
Then she brings the charged cloth close to the paper pieces.
She observes that the paper pieces are attracted to the cloth as well.
Ellie is confused why is it getting attracted even though the paper is not charged.
How would you explain this to Ellie?
So, when the negatively charged rod is brought next to the paper, the electrons in the paper are
repelled away. They may not move very far, but the effect is enough to give the surface of the
paper next to the rod, a positive charge. We say that a positive charge has been induced on the
paper.
The same process occurs when the positively charged cloth is brought next to the paper. The
electrons of the paper are attracted by the cloth. Hence the paper pieces gain a negative charge
on the surface.
Check out the force between charged and uncharged objects in the simulation:
https://phet.colorado.edu/sims/html/balloons-and-static-electricity/latest/balloons-and-static-elect
ricity_en.html
Q1: It’s your younger sister’s birthday tomorrow. You need to give her a surprise party at home.
The shops are closed due to lockdown. You quickly search for some decoration items, as she
sleeps in her room. What you get is only a leftover packet of balloons. Use the idea of static
electricity and think of an idea to decorate the walls with balloons, before your sister gets up.
Q2.
Good and bad conductors of electricity
Good conductors
Bad conductors (insulators)
A substance which allows electric current
to flow through it
A substance that does not allow electric
current to flow through it
All metals are good conductors of
electricity
Insulators are usually non metals.
Eg. aluminium, copper, silver
Eg : glass, wood, plastic