definitions Flashcards
Precision
- determined of the range in the values
Accuracy
- determined by the closeness of the values to the true value
High Precision
- measurements have a small range
Low Precision
- measurements have large range
Low accuracy
- the average of the measurements are not close to the
true value
Systematic Error
- constant error in all readings
- cannot be eliminated by averaging
- eg: zero error of measuring apparatus
Randon Error
- readings scatter equally about the true value
- errors can be eliminated by averaging
- eg: readings taken from different angles
Mass of a body
- mass is the quantity of matter in a body
weight
The force due to the gravitational field
Displacement
Distance from a fixed point in a specific direction
Linear momentum
mass x velocity
Torque of a couple
Product of force and perpendicular distance between 2 forces
Principle of moments
for a body in rotational equilibrium, sum of clockwise moment about a point is equal to sum of anti-clockwise moment about the same point
Pressure
Force acting perpendicularly to unit of surface area
Elastic limit
Elastic limit is a point beyond which the spring does not return to its original length when the load is removed
Ultimate Tensile Stress
The maximum value of the ratio force to the original cross-sectional area where the wire is able to support
Elastic Deformation
Change of shape or dimension and returns to original shape or size when the force applied is removed
Plastic Deformation
When the load is removed, the body does not return to original shape/length
Internal Energy
Sum of random kinetic energy and potential energy of the atom
Potential Energy
Stored energy available to do work
Elastic Potential Energy / Strain Energy
Energy stored in body due to deformation
Interference
When 2 or more waves meet at a point, the resultant displacement is equal to the vector sum of displacement of individual waves
Superposition
Constant phase difference between each of the waves
Progressive wave
Transfer of propagation of energy as a result of vibration
Polarisation
Vibration of particle in one normal to the direction of propagation of wave
Speed of progressive wave
Speed at which energy is transferred
Field line in an electric field
Path in which a free positive charge will move
Electric Field
Region where a charge experiences a force
Electric Field Strength
Force per unit positive small test charge
Electric Potential Energy
Energy converted from electrical energy to other forms of energy per unit charge
Electric current
rate of flow of charged particles
Charge
current x time
Random nature
The curve is not smooth
Spontaneous nature
The curve has the same shape with constant half life
Radioactive decay of a nucleus
Spontaneous and random decay of unstable nucleus become more stable by emitting alpha/beta particles /gamma rays
Spontaneous radioactive decay
Decay is not affected by the environmental changes such as temperature, pressure
Random decay
Constant probability of decay per unit time of nucleus and cannot predict which particular nucleus will deacy next
Random
the observations of the count rate shows variations
Alpha particle
Helium nucleus with 2 protons and 2 neutrons
Beta particle
High-speed electron
Gamma Radiation
Electromagnetic photon
what do the symbols represent in I=nave
A - cross-sectional area
N - number density of free electrons
v - drift velocity of free electrons
