Hertz Pitch and frequency
A conductor is something which allows electricity to pass through it
an example is a coin
An insulator is something which cannot allow electricity to pass through it
an example is plastic (or plastic cotton reel, plastic container ect.)
Static electricity is when you rub two things together to create static
I'm not sure if i helped on the last question but i am definitely sure of the first ones
Hi , here are some examples:
An astronomical unit
A parsec
A meter
Sound level at distance of 15 m is given as 20 dB
so intensity at this distance is given as



now if we move closer to some some distance the sound level is now 50 dB
now the intensity is given as



now we know that



so now the distance from friend must be 47 cm