F4 Flashcards
Specific latent heat of vapourisation
The quantity of heat absorbed during boiling or released during condensation of 1kg of a substance without any change in temperature
Specific latent heat
The quantity of heat absorbed or released during the change in phase of 1kg mass of a substance without any changes in its temperature
Specific latent heat of fusion
The quantity of heat absorbed during melting or released during freezing of 1kg of a substance without any change in temperature
Physical quantity
A quantity that can be measured
Base quantity
A physical quantity which cannot be derived from other physical quantities
Derived quantity
A quantity which can be obtained by combination of base quantities by mean of multiplication, division or both
Scalar quantity
Physical quantity that have magnitude only
Vector quantity
Physical quantity that have both magnitude and direction
Linear motion
Motion in a straight line
Speed
The rate of change of distance
Velocity
The rate of change of displacement
Acceleration
The rate of change of velocity
Free fall motion
Motion of an object which is affected by gravitational force only
Inertia
The tendency of an object to remain at rest or continue its uniform motion in a straight line at uniform velocity
Newton’s First Law of Motion
An object will remain at rest or move at uniform velocity unless acted upon by an external force
Momentum
The product of mass and velocity
Principle of Conservation of Momentum
The total amount of momentum before a collision is equal to the total amount of momentum after a collision provided there is no external force acting on the system
Force
A push or pull
Newton’s Second Law of Motion
The rate of change of momentum is directly proportional to the force and acts in the direction of the applied force
Impulse
The change in momentum
Impulsive force
The rate of change in momentum
Newton’s Third Law of Motion
For every action, there is a reaction with equal amplitude but opposite direction
Weight
The gravitational force acting on an object
Newton’s Universal Law of Gravitation
The gravitational force between two bodies is directly proportional to the product of masses of both bodies but inversely proportional to the square of the distance between the centre of the two bodies
Centripetal force
The force acting on an object in circular motion which acts in the direction towards the centre of the circle
Kepler’s First Law
All planets move in elliptical orbits with the Sun at one focus (Law of Orbits)
Kepler’s Second Law
A line that connects a planet to the Sun sweeps out equal areas in equal time (Law of Areas)
Kepler’s Third Law
The square of the orbital period of any planet is directly proportional to the cube of the radius of its orbit (Law of Periods)
Orbital radius
Average value of the distance between the planet and the Sun
Escape velocity
The minimum velocity needed by an object on the surface of the Earth in order to overcome the gravitational force and escape to outer space
Temperature
A measure of the degree of hotness or coldness of an object
Heat
The total amount of thermal energy that can be transferred from one object to another
Thermal equilibrium
The condition where the net heat transfer between two objects becomes zero
Heat capacity
The quantity of heat needed to raise the temperature of a substance by 1⁰C
Specific heat capacity
The quantity of heat energy needed to raise the temperature of 1kg mass of a substance by 1⁰C
Boyle’s Law
Pressure is inversely proportional to volume of a fixed mass of gas at constant temperature
Charles’ Law
Volume is directly proportional to absolute temperature of a fixed mass of gas at constant pressure
Gay-Lussac’s Law
Pressure is directly proportional to absolute temperature of a fixed mass of gas at constant volume
Oscilation, vibration
Repetitive motion about an equilibrium position in a closed path
Amplitude
Maximum displacement from its equilibrium position
Transverse wave
A wave which the vibration of particle in the medium is perpendicular to the direction of propagation of the wave
Longitudinal wave
A wave which the vibration of particle in the medium is parallel to the direction of propagation of the wave
Coherent sources
Source that produce waves which have the same frequency and constant phase difference
Period
The time taken by a particle to make one complete oscillation or by one source to produce one cycle of wave
Frequency
Number of oscillations made by a particle or number of cycles of waves produced by one source in one second
Wavelength
Distance between two consecutive points in phase
Wave speed
Distance travelled by a wave profile per second
The principle of superposition of waves
When two waves overlap, the resultant displacement is the sum of the two individual displacements of the two waves
External damping
Oscillating system loses energy to overcome air resistance or friction
Internal damping
Oscillating system loses energy because of the stretching and compression of the vibrating particles in the system
Damping
Reduction in amplitude in an oscillating system due to loss of energy
Resonance
When a periodic force is applied to an oscillating system at its natural frequency
Describe resonance in 4 sentences (pendulum)
- Pendulum X transfer energy to all pendulums
- Pendulum A has the same length as pendulum X
- Pendulum X forces pendulum A to oscillate in resonance with pendulum X
- pendulum A oscillates with max amplitude
Wavefront
Lines joining all points of the same phase
Refraction of waves
The change in direction of propagation of waves caused by the change of velocity of waves when the waves propagate from one medium to another
Diffraction of waves
The spreading of waves when the waves propagate through a slit or side of a barrier
Interference of waves
The superposition of two of more waves from a coherent source of waves
Constructive interference
occurs when two crests or troughs are in superposition to produce maximum amplitude
Destructive interference
Occurs when a crest and a trough are in superposition to produce zero combined ampltiude
Electromagnetic spectrum
7 types of electromagnetic waves that forms a continuous spectrum
Electromagnetic wave
Wave that is made up of an electric field and a magnetic field that oscillate perpendicularly to one another (E = horizontal, M = vertical)
Distance
Length of route covered by an object
Displacement
Shortest distance between the initial position and the final position in a specific direction
Refraction of light
A phenomenon when light changes direction when it travels from one medium to another medium of different densities
Refractive index
The ratio of speed of light in vacuum to the speed of light in medium
One law of refraction of light
When light travels from one medium to another medium, the incident ray, refracted ray and normal meet at one point and are in the same plane
Total internal reflection
The complete reflection of light ray at the boundary of two mediums with different optical densities when the angle of incidence in the higher optical density medium is greater than the criticla angle
Critical angle
Angle of i in higher optical density medium when the angle or r in lower optical density medium is equal to 90 degrees
Optical centre
Point at the centre of the lens
Principle axis (lens)
Straight line which passes through the optical centre of a lens and the centre of curvature for both surfaces of the lens
Axis of lens
Straight line through the optical centre and perpendicular to the principle axis
Focal point (lens)
Point located on the principle axis where :
- for convex lens, light parallel to the principal axis will converge at this point after passing through the lens
- for concave lens, light parallel to the principal axis will appear to diverge from this point after passing through the lens
Object distance (lens)
Distance between an object and optical centre of the lens
Image distance (lens)
Distance between an image and the optical centre of the lens
Focal length (lens)
Distance between the focal point and the optical centre
Principal axis (mirror)
Straight line through the centre of curvature and pole of spherical mirror
Centre of curvature
Centre of a sphere which produces a concave or convex mirror
Radius of curvature of mirror
Distance between the pole of spherical mirror and the centre of curvature
Focal point (mirror)
A point on the principal axis of the spherical mirror where :
- for convex mirror, light parallel to the principal axis will appear to diverge from this point
- for concave mirror, light parallel to the principal axis will converge at this point
Object distance (mirror)
Distance between object and pole of spherical mirror
Image distance (mirror)
Distance between image and the pole of spherical mirror
Focal length
Distance between focal point and the pole of spherical mirror
