T
Tangential
Tangent to a curve. In circular motion, used to mean tangent to the circle, perpendicular to the radial direction.
Temperature
A measure of the energy in a substance. The more heat energy in the substance, the higher the temperature.
Tensional stress
The opposite of compressional stress; occurs when one part of a plate moves away from another part that does not move.
Thermal Capacity
The quantity of heat required to raise the temperature of the whole body by one degree (1K or 1deg C) is called its thermal capacity.
Thermal energy
Thermal energy is used to mean the total amount of energy possessed by an object.
Thermal Equilibrium
When the two bodies in contact are at the same temperature and there is no flow of heat between them, these are said to be in thermal equilibrium. The common temperature of the bodies in thermal equilibrium is called the equilibrium temperature.
Thermal Expansion
The increase in the size of an object on heating is called thermal expansion.
Thermistor
A thermistor is a thermally sensitive resistor whose primary function is to exhibit a change in electrical resistance with a change in body temperature.
When subjected to low temperatures, the resistance of a thermistor is high.
When subjected to a high temperature, the resistance of a thermistor is low.
Thermocouple
When two different metals are joined together, they will convert heat energy into electrical energy. This is the basis of the thermocouple. Thermocouples are transducers.
Thermometer
It is a device used for numerical measurement of temperature. The commonly used thermometer is mercury thermometer.
Third law of motion
Whenever two objects interact, the force exerted on one object is equal in size and opposite in direction to the force exerted on the other object; forces always occur in matched pairs that are equal and opposite.
Time Period (of a wave)
The time taken by a wave to travel through a distance equal to its wavelength is called its time period. It is denoted by T. Time period of a wave=1/frequency of the wave.
Time Period (of an oscillation)
The time taken to complete one oscillation is called the time period of an oscillation. The time period of a pendulum does not depend upon the mass of the bob and amplitude of oscillation. The time period of a pendulum is directly proportional to the square root of the length and inversely proportional to the square root of the acceleration due to gravity.
Torque
The rate of change of angular momentum; a numerical measure of a force's ability to twist on an object.
Total Internal Reflection (TIR)
Total internal reflection occurs when light, instead of being refracted at a boundary between media of different densities, the light is totally reflected off the inside surface.
Tracer
Radioactive tracers are injected into a patient to examine the function of organs and blood supplies within the body. Technetium is often used as it emits gamma radiation which can be detected outside the patient's body.
Transducer
Any device which converts one form of energy into another. For example, a microphone, a TV, a car or a solar cell.
Transistor
A semiconductor device which can be used as an electronic switch.
Transformation
The mathematical relationship between the variables such as x and t, as observed in different frames of reference.
Transformer
A device used to increase or decrease electricity’s voltage and current, which consists of two separate coils. Transformers only work with a.c.
Transverse waves
A wave in which the particles of the medium oscillate in a direction perpendicular of the direction of propagation of wave is called the transverse wave. Water waves, light waves and radio waves are examples of transverse waves.
Trough
This refers to waves. The trough of a wave is simply the part of the wave with the least (most negative) amplitude.
Truth Table
A table showing the output logic states of a logic gate or logic system for all given combinations of input logic states.
Tuner (Radio or TV)
The tuner in a radio or TV allows the user to select one channel from the many channels which arrive at the aerial. The output signal from the tuner section is then passed to the decoder.
Two-stage Rocket
Essentially, two rockets one on top of the other. The top rocket will not ignite until the first rocket is finished and jettisoned. The advantage over a big single stage rocket is that all the dead weight of the empty first stage can be cut away and left to fall back to Earth. This can greatly reduce the total mass of fuel required to reach orbit.