Definition Flashcards
Define Scalar Quantity
Physical quantities that have magnitude only
Define Vector quantity
Physical quantities that have both magnitude and direction
Define Speed
Rate of change of distance
Define Velocity
Rate of change of displacement
Define acceleration
Rate of change of velocity
Define Uniform Acceleration
Constant Rate of Change of Velocity
Define Inertia
The mass of a body resists a change in the state of rest or motion of the body
Define Mass
The amount of substance in a body
Define Weight
Force of gravity acting on a body
Define Density
Mass per unit volume
Define Gravitational Field
A region in which a mass experiences a force due to gravitational attraction
Define Gravitational Field Strength
Gravitation Force per unit mass
Define Principle of moments
When a body is in equilibrium, the sum of clockwise moment about any pivot is equal to the sum of anti-clockwise moment about the same pivot
Define Centre of Gravity
Point about which the weight of the body seems to act
Define Pressure
Force acting per unit area
Define Principle of conservation of energy
Energy cannot be created nor destroyed, but can be converted from one form to another. Total energy in an isolated system is constant
Define Energy
Capacity to do work
Define Work Done
Product of Force and distance moved in the direction of the `force
Define Power
Rate of doing work or energy conversion
Define Conduction
The transfer of thermal energy through a medium without any flow of the medium
Define Convection
The transfer of thermal energy by means of convection current in a fluid (liquid or gas), due to a difference in density
Define Radiation
The transfer of thermal energy in the form of electromagnetic waves such as infrared radiation, without the aid of a medium
Define Wave speed
Distance moved by a wave in a second
Define Frequency
Number of completed waves produced per second
Define Wavelength
Distance between any two identical point on successive waves
Define Period
Time taken to produce one complete wave
Define amplitude
The maximum possible displacement of a point from its rest position
Define Wavefront
Line that joins all identical points on a wave
Define transverse wave
Wave that travels in a direction perpendicular to the direction of vibrations
Define longitudinal wave
Wave that travels in a direction parallel to the direction of vibration
Define Ultrasound
Sound with frequency exceeding the upper limit of human hearing of 20000Hz
Define current
Rate of flow of charge
Define Electromotive Force
Work Done by a source in driving a unit charge around a complete circuit
Define Potential Difference
Work Done to drive a unit charge through the component
Define Resistance
The ratio of the potential difference across a component to the current flowing through the component
Define Fuse
Prevent excessive current flow due to faults like short circuit, by melting and becomes an open circuit. Prevent fire and equipment damaged
Define fuse rating
The maximum allowable current to flow through a fuse before it blows
Define Circuit Breaker
Trip and switch off the electrical supply in a circuit when there is an excessive flow of current. Prevents fire and equipment damaged
Define live wire
- Live Wire is colour-coded brown
- Deliver electrical energy to the appliance, connected to a high potential (240V)
Define Neutral Wire
- Neutral Wire is colour-coded blue
- Completes the circuit by forming a path for current to flow back to the supply, connected to zero potential (0V)
Define Earth Wire
- Earth Wire is colour-coded green and yellow
- Is a safety device by allowing unusually large current to flow through it, instead of the user. Usually zero current. Prevents electric shocks.
