Sunday 22 December 2013

SUBSTANCE : CONCEPT AND FAQs

Substance : CONCEPT & FAQs


SUBSTANCE : CONCEPT AND FAQs

Here are some important concepts in physics topic substance


Q: What is a substance in physics?

A: In physics, a substance is any material that has a specific set of physical and chemical properties. A substance can be an element, a compound, or a mixture.

Q: What are the physical properties of a substance?

A: The physical properties of a substance include its mass, volume, density, boiling point, melting point, specific heat, and thermal conductivity.

Q: What are the chemical properties of a substance?

A: The chemical properties of a substance include its reactivity, combustibility, acidity, and basicity.

Q: What is the difference between an element and a compound?

A: An element is a substance made up of only one type of atom, while a compound is a substance made up of two or more different types of atoms chemically bonded together.

Q: What is a mixture?

A: A mixture is a substance made up of two or more different substances that are physically combined and can be separated by physical means.

Q: What are the types of mixtures?

A: There are two types of mixtures: homogeneous and heterogeneous. Homogeneous mixtures have a uniform composition throughout, while heterogeneous mixtures have a non-uniform composition.

Q: What is a solution?

A: A solution is a homogeneous mixture of two or more substances that are evenly distributed at the molecular or ionic level.

Q: What is an alloy?

A: An alloy is a mixture of two or more metals, or a metal and a non-metal, that has properties different from those of the individual elements.

Q: What is density?

A: Density is the amount of mass per unit volume of a substance. It is usually expressed in units of grams per cubic centimeter (g/cm3) or kilograms per cubic meter (kg/m3).

Q: How is density measured?

A: Density is measured by dividing the mass of a substance by its volume.

Q: What is specific heat?

A: Specific heat is the amount of heat energy required to raise the temperature of one gram of a substance by one degree Celsius.

Q: What is thermal conductivity?

A: Thermal conductivity is the ability of a substance to conduct heat. It is usually expressed in units of watts per meter per degree Celsius (W/m·°C).

Q: What is the difference between heat and temperature?

A: Heat is the transfer of thermal energy from one object to another, while temperature is a measure of the average kinetic energy of the particles in a substance.

Q: What is a phase change?

A: A phase change is a physical change in which a substance changes from one phase (solid, liquid, or gas) to another phase.

Q: What is a phase diagram?

A: A phase diagram is a graph that shows the conditions of temperature and pressure at which different phases of a substance exist.

Q: What is a critical point?

A: A critical point is the point on a phase diagram where the liquid and gas phases of a substance have the same density and are indistinguishable from each other.

Q: What is sublimation?

A: Sublimation is the process in which a solid changes directly into a gas without passing through the liquid phase.

Q: What is fusion?

A: Fusion is the process in which a solid changes into a liquid.

Q: What is vaporization?

A: Vaporization is the process in which a liquid changes into a gas.

Q: What is condensation?

A: Condensation is the process in which a gas changes into a liquid.

Q: What is freezing?

A: Freezing is the process in which a liquid changes into a solid.


Q: What is melting?

A: Melting is the process in which a solid changes into a liquid.

Q: What is the law of conservation of mass?

A: The law of conservation of mass states that in a closed system, the mass of the system remains constant, regardless of any physical or chemical changes that may occur within the system.

Q: What is the law of conservation of energy?

A: The law of conservation of energy states that energy cannot be created or destroyed, but it can be transformed from one form to another.

Q: What is kinetic energy?

A: Kinetic energy is the energy that an object possesses due to its motion.

Q: What is potential energy?

A: Potential energy is the energy that an object possesses due to its position or configuration.

Q: What is thermal energy?

A: Thermal energy is the energy that is transferred between objects due to a temperature difference.

Q: What is a wave?

A: A wave is a disturbance that travels through a medium or space, transferring energy from one point to another.

Q: What is amplitude?

A: Amplitude is the maximum displacement of a wave from its equilibrium position.

Q: What is frequency?

A: Frequency is the number of waves that pass a point in a given amount of time. It is usually expressed in units of hertz (Hz), which is equal to one cycle per second.

Q: What is wavelength?

A: Wavelength is the distance between two consecutive points on a wave that are in phase.

Q: What is the speed of light?

A: The speed of light is approximately 299,792,458 meters per second in a vacuum.

Q: What is refraction?

A: Refraction is the bending of a wave as it passes through a medium with a different refractive index.

Q: What is reflection?

A: Reflection is the bouncing of a wave off a surface.

Q: What is diffraction?

A: Diffraction is the bending of a wave around an obstacle or through a narrow opening.

Q: What is interference?

A: Interference is the combination of two or more waves that results in a new wave pattern.

Q: What is a photon?

A: A photon is a particle of light or electromagnetic radiation.

Q: What is the photoelectric effect?

A: The photoelectric effect is the emission of electrons from a material when it is exposed to light or electromagnetic radiation.

Q: What is nuclear fusion?

A: Nuclear fusion is the process in which two atomic nuclei combine to form a heavier nucleus, releasing a large amount of energy in the process.

Q: What is nuclear fission?

A: Nuclear fission is the process in which the nucleus of an atom is split into two or more smaller nuclei, releasing a large amount of energy in the process.





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