Corrections Nov 2009 Flashcards
What is meant by the term half life?
Amount of time for half a radioactive atom to decay?
Name an example of electrical heating used in the home
Toaster or oven or kettle
What does an alpha particle consist of?
Helium atom; 2 protons and 2 neutrons
What is work done?
The force times distance moved in the direction of the force
What’s the equation for power?
Power= work done/time taken
What 3 things do magnetic field lines show?
Direction is from North to South
They show the shape of a mag field
They can show the strength of a mag field
What does equilibrium mean?
Forces are equal, total anti-clockwise moment is equal to total clockwise moment
FLHR - what does first finger show?
Direction of mag field from North to South
FLHR - what does thumb show?
Direction of force
FLHR - what does second finger show?
Direction of current from positive to negative
Name 2 devices which use an electromagnetic force acting on a wire which carries a current in a mag field
Electric motor
Loudspeaker
How can a wire carry a current in a mag field but no electromagnetic force act on it?
Wire/current is parallel to mag field
State the equation which relates acceleration, mass and unbalanced force?
Unbalanced force= mass x acceleration
F=mxa
What is voltage?
Voltage is the energy transferred per unit charge passed
What is in a pair of binoculars to pass the ray of light?
Prism
