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
Why would refraction not occur?
Angle of incidence is bigger than critical angle
Stage the equation which relates critical angle (c) and refractive index (n)
Sin c = 1/n
State the equation which relates frequency, speed and wavelength
Speed = frequency x wavelength
How is heat used to generate electricity in a nuclear reactor?
Steam produced in boiler
This drives the turbine
Which rotates the generator
