Physics Dictionary with definitions of all most important physical meaning with physics terms. All of the short questions, MCQs and True False Physics MCQs physics words with solve all questions.
Waves: Transfer energy in the direction they are traveling.
Amplitude: The maximum displacement of a point on the wave from this undisturbed position.
Wavelength: The distance between the same point on two adjacent waves (between the trough of one wave and the trough of the wave next to it, applies the same way with the crest,).
Frequency: Is the number of complete waves passing a certain point per second. Frequency is measured in Hertz (Hz), where 1 wave is 1 Hertz.
Period: From the frequency, you can find a period of a wave using the formula 1÷frequency.
Transverse waves: Waves were in which the oscillation (vibrations) are perpendicular (90 degrees) to the direction of energy transfer. Some of these waves include All electromagnetic wave (light)Ripples and waves in watera wave on a string.
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Amplitude: The maximum displacement of a point on the wave from this undisturbed position.
Wavelength: The distance between the same point on two adjacent waves (between the trough of one wave and the trough of the wave next to it, applies the same way with the crest,).
Frequency: Is the number of complete waves passing a certain point per second. Frequency is measured in Hertz (Hz), where 1 wave is 1 Hertz.
Period: From the frequency, you can find a period of a wave using the formula 1÷frequency.
Transverse waves: Waves were in which the oscillation (vibrations) are perpendicular (90 degrees) to the direction of energy transfer. Some of these waves include All electromagnetic wave (light)Ripples and waves in watera wave on a string.
Longitudinal waves: Waves were the oscillation (vibrations) are parallel to the direction of energy transfer. Some of these waves include Sound wave in air, ultrasound: Shock waves, some seismic waves.
Wave speed formula: Wave speed (v)=Frequency(Hz)x Wave length (ƛ).
Absorbed waves: Where waves are absorbed by the material that it is trying to cross into, this transfers the energy to the material where it gets stored in.
Transmitted waves: Where the waves carry on traveling through the material. This often leads to refraction.
Ray diagrams for reflection: When you make a ray diagram for reflection you need to remember that Angle of incidence=Angle of reflection: The angle of reflection is the angle between the incoming wave and the normal: The angle of reflection is the angle between the normal wave and the reflective wave : The normal wave is an imaginary line that perpendicular to the surface at the point
of incidence, shown at a dotted line.
Specular reflection: When a wave is reflected in a single direction by a smooth surface.
Diffuse reflection: When a wave is reflected by a rough surface and the reflected rays are scattered in lots of different directions.
Electromagnetic waves: Are transverse waves that transfer energy from a source to an absorber. They travel through air or vacuum at the same speed. There are a variety that increase in frequency overtime.
Refracted waves: When a wave changes direction between materials.
Radio waves: These are electromagnetic waves that are made by using an electrical circuit. The object in which charges the (electrons) oscillating to create the radio waves. This object is called a transmitter. When radio waves reach a receiver, the radio waves are absorbed. The energy carried by the waves is transferred to the electrons in the material of the receiver. This energy causes the electrons in the circuit, if the receiver is part of a complete electrical circuit, to generate an alternating current which is of the same frequency of the radio waves.
Long radio waves: Wave lengths (1-10km) these can be transmitted from one place on the planet to the other side of the world. This is because these wavelengths can also diffract around hills, into tunnels etc. This makes it possible for radio signals to be received even if the receiver isn't in in the line of sight of the receiver.
Short radio waves: Wave lengths (1-10m) can like long radio waves be received at long distances from the transmitter. That's because they are reflected from the ionosphere-an electrically charged layer in the earths upper atmosphere.
Bluetooth: These use short radio waves to send data over short distances between devices without wires (e.g. Wireless headsets so you can use your phone while driving a car.
Medium radio waves: These wave signals (the shorter version) can also reflect from the ionosphere, depending on atmospheric conditions and the time of day.
TV and FM radio: Low frequency electromagnetic radiation used to transmit information such as television and radio programmed. To connect to to the TV or FM transmitting have to have very short wavelengths. To get reception, you must be in direct sight of the transmitter-the signal doesn't bend or travel far through buildings.
Microwaves and satellites: Communication to and from satellites (including satellite TV signals and satellite phones) uses microwaves. But you need to use microwaves which can pass easily through the earths watery atmosphere. For satellites TV, the signal from a transmitter is transmitted into space where it picked up by the satellite receiver dish is orbiting thousands of kilometres above the earth. The satellites transmits signals the signal back in a to earth in a different direction where it's received by a satellite dish on the ground. There is a slight time delay between it being completed because of the long distances the signal has to travel.
Microwave oven: Electromagnetic radiation with a frequency between that of visible light and radio waves. In the microwave ovens the microwaves need to be absorbed by water molecules and food-so they use a different wave length to those used in satellite communications. The microwaves penetrate up to a few centimeters into food before being absorbed and transferring the energy they are carrying to the water molecules in the food, causing the water heating up. The water molecules then transfer this energy to the rest of the molecules in the food by heating-which quickly cooks the food.
Infrared Waves: Radiation which transfers heat energy. Part of the electromagnetic spectrum with a longer wavelength than light waves but a shorter wavelength than radio waves.
Fibre Optic Cables: They are cables made up of thin glass or plastic fibers that can carry data (.e.g. From telephones and computers) over a long distance using light. The light bonces off the sides of the wires wall meaning it always goes in one direction.
Ultraviolet Waves: Ultraviolet light is a form of radiation which is not visible to the human eye. It's in an invisible part of the "electromagnetic spectrum". Radiated energy, or radiation, is given off by many objects a light bulb, a crackling fire, and stars are some examples of objects which emit radiation.
X-Rays: X-rays are a very energetic form of electromagnetic radiation that can be used to take images of the human body. It can look through things such as flesh and wood, but not metal.
Sound waves: These are caused by vibrating objects. These are passed through the surrounding area as a series of compression's an rarefaction's. These travel faster in more solid states of matter as it is more easier to vibrate the particles to make sound if there close together, rather than far apart. This is why in a vacuum, where there are no particle's there is no sound.
Ultrasound: These are sounds that are at a higher frequency than 20,000 Hz. This is called ultrasound as its at a higher frequency than humans can here. It can be useful in things such as scanning of the foetus as the timings and distribution of the sound waves are processed by the computer who uses the echo's that follow to find the foetus.
P-Waves: These are longitudinal waves tat travel through solids and liquids. They have the have the capabilities to travel through the earths core.
S-Waves: These are transverse waves and cannot travel through liquids, such as the earths core. They are made by earthquake and it is easy to see where from as they leave a shadow on one side meaning on the opposite side of the earth to the shadow there has been a earthquake.
Magnets: Magnets are materials such as iron, nickel, and cobalt that can experience a non-contact force similar to forces on an electric field. They have a North Pole and South Pole.
Magnetic feild: The magnetic field goes from north to south you can show this by drawing arrows on your lines going south. The closer together the lines are, the stronger the magnetic field.
Compasses and magnets: Inside a compass is a tiny magnet, with the North Pole being attracted to any other magnet that it is near. You can place compasses around a magnet to build a picture of the magnetic field. When there is no magnet near the compass uses the earths magnetic field and points north.
Permanent magnets: Magnets that produce there own magnetic field.
Induced magnets: Magnets that are magnetic when placed in the area of a magnetic field.
Wire and there magnetic field: When a wire gains electricity it grow a magnetic field perpendicular to the wire.
Solenoid: A solenoid is when you increase the magnetic field by making coils of of wires around it.
Electromagnets: Electromagnets are magnets that turn or off when an electric current is passed through it. They are used to lift things up or down and can be used with other circuit as a switch.
Size of force equation: Force=Magnetic flux density(B)xcurrent(I)Xlenght(l).
Fleming's left hand rule: Fleming's left hand rule is were your left hand first finger = the direction of field Your second finger = which ways the current is going: And your thumb = the force the magnet going in.
The motor effect: The motor effect is where a current carrying wire (or any other conductors) is put between magnetic poles, the magnetic field around the wire interacts with magnetic field it has been placed in. This causes the magnet and the conductor to exert forces on each other causing the wire to move either up or down.
Convex lens: These lens bulge outwards. It causes the rays to converge parallel to the axis at the principle focus.
Concave lens: These lens cave in on itself. This causes parallel waves of light to spread out.
Axis of a lens: The line passing through the middle of the lens.
Principle focus of a convex lens: The principle focus of a convex lens is after all the light hits the the lens and hits each other at axis.
Principle of a concave lens: The principle focus of a concave lens is before the lens were it appears all the light comes from.
Focal length: The distance of the central focus to the principle focus.
Real image: A real image is a image where the light of an object comes together to form an image on the 'screen'.
Virtual image: A virtual image is where the rays diverge so it the light comes from a completely different place.
Infrared radiation: All objects take in infrared radiation and emit it. When an object is hot it emits more infrared and when it's cold it absorbs more.
Types of energy: Some types of energy are : Kinetic energy: Gravity potential energy: Heat energy: Light energy Thermal energy: Geothermal energy: Nuclear energy: Chemical potential energy.
Law of Conservation of Energy: The law of conservation of energy is the rule that energy cannot be created or destroyed.
Wasted energy: Energy is often wasted as heat but can also be things such as sound etc.
Insulation: Insulation is material that are used in things like buildings to reduce heat transfer and keep as much heat inside.
Energy changes: Energy changes is when energy transitions between different types of energy, for example gravity potential energy changing into kinetic energy.
U-value: The U-value is the amount of heat that can be lost from a building. The lower the U-value in this the better heat efficiency there is.
Thermal flask: A thermal glass has a Plastic lid that dose not become hot with conduction and convection A vacuum layer so no energy can get through Plastic base easy to hold because it has little heat conduction Outer layer is mirrored to reflect the heat back in.
Capacity: Capacity is the amount needed to lift 1kg by 1 degree.
Physics Figures For Short Questions, MCQs Test Preparations.
Now I Will Explain here the figs. of Most Important Physics For test preparations Cell, Battery, Switch open, Switch closed, Filament bulb, Fuse, L.E.D, Resistor, Variable Resistor, Ammeter, Volts, Diode, Light Dependent (L.D.R), Thermistor etc.
Electric Current (Amps): The flow of an electric charge. The unit of this is ampere (A).
Potential difference (Voltage: Is the driving force that pushes the charge around. Measured in volts (V).
Resistance: Anything that slows down the flow of the current. Measured in ohms (Picture).
Rate of the flow of charge: When current flows part a ceartin pointfor a ceartin lenght and time. Measured in coulombs (Q).: In the equation Q=current(I)xtime(t) in secounds.
Potential difference (Voltage): Voltage=Current X Resistance.
Ammeter: Measures the current in Amps. Must always be in the series of the circuit current is the same everywhere.
Voltmeter: Measures the voltage in volts. Only able to measure the voltage when placed in a parallel circuit. Voltage is shared in all parts of a circuit.
Resistance: The longer the length of wire the higher the resistance goes up in solid line. Resistance all adds up.
Filament light bulb: The higher the temperate the higher the resistance.
Diode: Flows fine in one way but has a very high resistance in the other.
Light Dependent Resistor (L.D.R): Dependent on the intensity of light. In bright light the resistance fall. In darkness the resistance increases.
Thermistor: A temperature dependent resistor. In hot conditions, the resistance drops. In cool conditions the resistance rises. Useful in car engine sensors to turn the engine off if it reaches a certain point.
Static Electricity: When certain insulating materials rub together, negatively charged electrons a rubbed onto each other leaving materials electrically charged.
Vector quantity forces: Vector quantity forces have a magnitude (power) and a direction. These are forces such as: velocity, displacement, acceleration and momentum. Vector forces are usually represented by an arrow with the length of the arrow showing the magnitude of the force as well as the direction it is going in.
Scaler quantity forces: Scaler quantity forces are forces with magnitude but no direction. These are things such as: speed, distance, mass, temperature and time.
Contact forces: Contact forces work when two or more objects are touching. Some examples of this are: friction, air resistance, tension in ropes and normal contact force. When these two or more objects interact there is a force on both of them and is equal or opposite of the other object.
Non-contact forces: Non-contact forces happen when two or more objects exert a force on each other but are not touching. Some examples of these are: magnetic force, gravitational force, electrostatic force. When these two or more objects interact with each other there is a force produced on all of them that is equal or opposite.
Using scale drawings to find resultant forces: To find a resultant force you can draw a scale drawing. You can do this by:: Drawing all the forces on the object to scale, 'tip-to-tail': Then draw a straight line from the start of the first force to the end of the last force, this is a resultant force.: Measure the length of the resultant force on the diagram to find the magnitude and the angle to find the direction of the force.
How to show forces in equilibrium by a scaled drawing: If all forces acting in a object combine to make zero the object is in equilibrium. You can show this by a scaled drawing. You do this by:: Drawing the tip of the last force you drawn where the tail of the first begins. They should both be the same length. And if there is more than one force on one of the sides they should equal to be the same size as the lone force.
Elastic objects: Elastic objects are objects that when more than one force is applied to them and the object is elastically Deformed, it can go back to its original shape and length once the force has been removed. Work is done when the forces that were used to stretch or compress an object have been transferred to form elastic potential energy.
Extension and force: The extension of a stretched spring (or other elastic object) is directionally proportional to force applied. The equation is:: Force(newtons) = Extension(meters) Or F(newtons)=Ke(meters) This equation also works for compression where e is the difference between the natural and compressed lengths.
Limit of extension: However there is a limit to o the amount of force you apply and the extension to go up proportionally. It can be well shown on a graph where the graph curves and the numbers of the extension and the force are no longer the same. This is known as the limit of proportionality and is shown usually with a point marked p at that point.
Moments of force: A moment of force is the turning or rotation of a force around a pivot. This can be shown by the equation : Moment of a force(newton meters) = Force(newtons) X Distance from the pivot(meters): To increase the moment you need to increase the force applied or or the distance from the pivot. The opposite should be done if you want to make the moment smaller.
Using a leaver: A leaver can be used to increase the distance from the pivot at which the distance is applied. Since M=Fd this means less force is needed to make the same moment meaning a leaver is easier.
Pressure: Pressure is the amount of force applied over a certain area (the concentration/density of particles applying force in a certain area). This can be shown in the equation Pressure in pascals(Pa) = force normal to a surface (newtons) ---------------------------------------: Area of that surface (m2).
Pressure of a liquid: Pressure has the ability to exist in a liquid. This particular amount of pressure is dependent on the depth and density of the liquid. The density of a liquid is compactness of that substance, how close all of the particles are. The more dense a liquid is, the more particles it has in a certain space meaning a higher amount of collisions between the particle increasing the pressure. As the depth of the liquid increases, it means the amount of particle above that particular point increases. You can calculate pressure in a liquid through the equation Pressure(Pascals)=height of color of liquid(m) X the density of liquid (kg/m3) X gravitation field strength(9.8 N/kg).
Upthrust: When a liquid is submerged in water pressure is exerted on it in every direction. The pressure increases with depth, so the force at the bottom is greater than the force at the top. This causes a resultant force upwards called upthrust. This upthrust is equal to the weight of that particular object. However if the object is denser than the liquid it will sink.
Atmospheric pressure: Atmospheric pressure is created on the surface of air molecules colliding with the surface. As the altitude (height above earth) increases the air pressure deacreases. This is because the higher the altitude there are less air molecules to collide with each other reducing the pressure.
Density: Density is how much mass fit in an objects volume and is measured in kg/m3.
Measuring the density of a solid or liquid: To measure the density of a solid or liquid you measuring its volume of the solid or liquid and then divide that by its mass which you can find on a weighing scale.
Finding the density of a regular shaped solid: To find the density of a regular shaped object you measure its volume and divide it by its mass which you can find when using a weighing scale.
Finding the density of a irregular shaped object: To find the density of a irregular shaped object you find the volume by placing the object inside a eureka can and then finding the volume of the water displaced, and then dividing this by the mass that you can find on a weighing scale.
The density of water: The density of water is 1000kg/m3, if an objects density is less than that then it will float in water.
Properties of a solid: The particles of a solid are held together next to each other in fixed positions. This leads to the, being the least energetic of the 3 states of matter. To change a solid to any others of the states of matter, energy through anything must be provided to break the particles up. (Include picture).
The properties of a liquid: At least half of the particles in a liquid are touching in a liquid and are able to move over each other and form irregular arrangement. However liquids are able due to this to move a bit at random and are more energetic then solids. In order to fully break down the particles energy must be provided in some way for this to happen.
The properties of a gas: Gas particles are not held together and are allowed to move around freely to roam around. These particles are much more energetic than liquid and solid particles. To put these particle back into a somewhat structured state energy must be released from the particles in some way.
A change of state converse mass: (Put picture here).
Internal energy and change in state: Inside the state of an object the particles in the object bounce into each other and anything around them. This total energy in an object is known as internal energy. Increasing something, such as the temperature of an object can have an impact on the object, what happens is the particles inside the object speed up vibrating more. This can cause a change in state if the particles then begin to break up going up into a liquid or gas. This is the same going the opposite way round.
Specific latent heat: Specific latent heat is the energy needed to for a substance to change its state without the temperature changing. For cooling, specific latent heat is the energy released by a change in state.
Particle motion in a gas: The pressure in a gas is caused by the random collisions of gas molecules on surfaces that are in contact with the gas. This can be increased if you decrease the volume, increase the amount of gas particles, use a more denser gas or increase the heat/temperature.
Isotopes: Isotopes are atoms from the periodic table that are slightly different. They will have the same amount of electrons and protons as a regular atom but with more neutrons in the atoms nucleus. These isotopes of normal atoms are often unstable and tend to decay into other atoms and give off radiation as they attempt to become more stable.
Radioactive decay: When an isotope of an atom from the periodic table is formed it is often unstable. These isotopes, due to this, begin to decay in a bid to become stable. Radioactive substances begin to then spit out these are gamma, beta and alpha radiation, they can also release neutrons to re balance there atomic and mass number.
Ionizing radiation: Ionizing radiation is radiation that knocks electrons off atoms, creating positive ions. The ionizing power of a radiation source is how easily it can do this.
Alpha particle: Alpha radiation is when an alpha particle (symbol is picture) is emitted from the nucleus.an app particle is 2 neutrons and protons (like a helium nucleus). They don't penetrate very far into materials and are stopped quickly. Because of their size they are strongly ionizing and can be absorbed by just a Piece of paper.
Beta particle: A beta particle (symbol is picture) is just a fast moving electron released from the nucleus. Beta particles have virtually no mass and have a -1 charge. They are moderately ionizing. They penetrate moderately far into materials before colliding and have a range of a few meters in air. They are absorbed by a sheet of aluminium around 5mm. For every beta particle emitted, a neutron in the nucleus has turned into a proton.
Gamma rays: Gamma rays (symbol in picture) are waves of electromagnetic radiation released by the nucleus. They penetrate far into materials without being stopped and will travel long distances in air. This means they are weak at ionizing because they tend to pass through air rather then colliding with atoms eventually they will hit something and do damage. They can be absorbed by thick sheets of lead or metres of concrete.
