Sparks Flashcards
what does an atom consist of?
a small positively charged nucleus surrounded by an equal number of negatively charged electrons
what are electrostatic effects due to?
the movement of electrons
what do the same charged electrons do?
repel each other
give an example?
hair
what do unlike charges do?
attract
give an example?
a balloon stuck to the ceiling
what happens when a polythene rod is rubbed with a duster?
electrons are transferred from the duster to the polythene making the polythene rod negatively charged
what happens when an acetate rod is rubbed with a duster?
electrons are transferred from the acetate to the duster, leaving the acetate rod positively charged
why would an object either have a positive or negative charge? (2 separate points)
posotive- due to a lack of electrons
negative- due to an excess of electrons
what happens if a person touches something at a high voltage?
large amounts of electrical charge may flow through their body toward the centre of the earth
what are dust and dirt attracted to? and give an example?
insulators, such as television screens
what do clothes made from the same synthetic materials often cling to?`
each other and to the body
name 2 ways in which electrical shocks can be avoided n industry?
- shoes with insulated soles are worn by workers if there is a risk of charge building up so that charge cannot flow through them to earth
- fuel tankers are connected to an aircraft by a conducting cable during refuelling
what prevents a build up of charge in anti-static sprays, liquids and cloths?
they are made form a conducting material which carry away electric charge
what can cause ignition to gases or vapours which cause explosions?
when inflammable gases or vapours are present, or there is a high concentration of oxygen, a spark from static electricity could ignite
what are metals good at?
allowing electric charges to move through them (good conductors)
what do insulators not allow?
then do not allow electrical charges through them
how can an insulator be charged?
by friction
explain what is in a neutral atom?
there are the same number of positive and negative charges
what does a van de graaff generator do?
collects electric charge on a metal dome
explain what happens when a person places there hand on a van de graaff generator?
a person places there hand on the dome, the dome is switched on and the person becomes charged, all the persons hairs gain the same charge so repel each other and stick up
how can a person become charged by walking on vinyl?
because of the friction causes earthing
why are oil tankers first filled with inert gas such as nitrogen?
to avoid a spark that can cause an explosion
why cant mobile phones be used on petrol station forecourts?
to prevent sparks that cause explosions
