Points to remember in Physics Part 6

Points to remember in Physics
Part 6

51. What is the best conductor of electricity?

Ans: salt water. 
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The best answer is:

Saltwater is a decent conductor of electricity compared to pure water, but it is not as good as most metals or conductive materials. 

The salt in saltwater dissociates into ions that are able to carry electrical charges through the water, making it a better conductor than pure water. 

However, it is still not as good as materials like copper or silver.

The conductivity of saltwater can also vary depending on the concentration of salt and temperature.

52. Which is used as a coolant in nuclear reactors?
– Liquid sodium

The best answer:

Liquid sodium is not commonly used as a coolant in nuclear reactors. 

The most commonly used coolants in nuclear reactors are water, heavy water, or a combination of water and boric acid. 

There are some specialized reactors that use other coolants such as liquid metal (e.g. liquid sodium or lead) or gas (e.g. helium). 

However, these types of reactors, use of liquid sodium, are less common and are typically used for specific purposes such as Research or Naval propulsion.

53. Optic fibres are mainly used for which purpose?
– Communication

True.

Yes, optic fibers are mainly used for communication purposes. 

They are used to transmit information over long distances by converting electrical signals into light signals, which are then sent through the fiber. 

Optic fibers can carry large amounts of data over long distances with very little signal loss or degradation. This makes them ideal for use in telecommunications, internet connectivity, cable television, and other applications that require high-speed data transmission over long distances.

54. Mesons are found in which rays?
– Cosmic rays

Yes, mesons are found in cosmic rays. Cosmic rays are high-energy particles that originate from outer space and collide with Earth's atmosphere. 

Mesons are a type of subatomic particle that are produced in these collisions. 

They are unstable particles and decay quickly, but their detection in cosmic rays has provided valuable insights into the nature of subatomic particles and the universe as a whole.

55. Old-written material, which cannot be read easily, how can it be read?
– By infrared rays

Yes, infrared rays can be used to read old-written material that cannot be easily read with the naked eye. 

This technique is called infrared reflectography or infrared imaging. 

Infrared rays are able to penetrate the surface of the material and reflect off the underlying layers, revealing the hidden text or image. 

This method is particularly useful for reading faded or obscured text on old manuscripts or documents without causing any damage to the original material. 

In addition, the use of infrared imaging has also allowed researchers to discover new insights into the history and culture of ancient civilizations.

56. In an atomic nucleus, by which force are neutrons and protons held together?
– Exchange forces

In an atomic nucleus, neutrons and protons are held together by the strong nuclear force. This force is also known as the strong interaction or strong force. It is a fundamental force of nature that acts between particles with quarks, such as protons and neutrons. 

The strong force is responsible for binding the nucleus together despite the repulsive electromagnetic force between positively charged protons. 

The strong force is mediated by the exchange of particles called gluons and is much stronger than the electromagnetic force or the weak force, which is responsible for radioactive decay. 

The strong force only acts over very short distances, but it is essential for understanding the structure and stability of atomic nuclei.

57. Which purified oil does Aviation fuel for jet aeroplanes consist of?
– Kerosene

Yes, aviation fuel for jet airplanes typically consists of a purified form of kerosene, which is a type of fuel oil that is derived from petroleum. 

Jet fuel is also known as aviation turbine fuel (ATF) and is a highly refined, clear liquid that is used to power gas turbine engines in aircraft. 

The most common type of jet fuel is Jet A-1, which is a kerosene-based fuel that has a flash point of 38°C (100°F) and a freezing point of -47°C (-53°F). 

Jet A-1 is used in commercial aviation and is also widely used in military aircraft. It is chosen as the fuel for jet airplanes because of its high energy density, stability, and reliability.

58. Who received Nobel Prize twice for the same subject?
– Marie Curie

Yes, Marie Curie is the only person to have received Nobel Prize twice for the same subject. She was awarded the Nobel Prize in Physics in 1903, along with her husband Pierre Curie and Henri Becquerel, for their work on radioactivity. 

Later, in 1911, she was awarded the Nobel Prize in Chemistry for her discovery of the elements radium and polonium, and for her pioneering work in the field of radioactivity. 

She is also the first woman to have been awarded a Nobel Prize and the only woman to have received two Nobel Prizes. 

Her contributions to science, particularly in the fields of radioactivity and nuclear physics, continue to inspire scientists and researchers to this day.

59. What does Every object at a temperature above absolute zero?
– Radiates energy

Yes, every object at a temperature above absolute zero radiates energy in the form of electromagnetic radiation, which includes visible light, infrared radiation, and ultraviolet radiation, among others. 

This phenomenon is known as thermal radiation, and it occurs because all objects contain charged particles, such as electrons and protons, which are in constant motion. 

As these particles move, they generate electromagnetic waves that radiate away from the object. The amount and frequency of the radiation emitted depend on the temperature and physical properties of the object. This is why hot objects, such as the sun or a light bulb, appear to emit more radiation than cooler objects, such as the human body or a rock. 

The study of thermal radiation and its properties is an important area of research in physics and engineering, with applications in areas such as thermodynamics, energy transfer, and materials science.

60. By whom was Electron first identified?
– J. J. Thomson

Yes, J. J. Thomson was the first scientist to identify the electron. 

In 1897, he conducted a series of experiments using a cathode ray tube, which is a sealed glass tube that contains a low-pressure gas and two electrodes. 

When an electric current is passed through the tube, it produces a beam of electrons that travel from the negative electrode (the cathode) to the positive electrode (the anode). 

Thomson observed that the cathode rays were deflected by an electric field and a magnetic field, indicating that the rays were composed of negatively charged particles. He called these particles "corpuscles," which later came to be known as electrons. 

Thomson's discovery of the electron revolutionized the field of physics and laid the foundation for the development of modern electronics.

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