Category: Physics Notes PPT

An atom which consists of particles too small are known as subatomic particles. One of the subatomic particles is known as deuteron.

In , this comprehensive section of the Physics chapter explains about deuteron and its mass. The website provides easy downloadable pdfs to the students for them to understand the definition of deuteron mass, how to determine its value and note the important difference between deuteron and deuterium. 

What is a Deuteron?

The deuteron is a subatomic particle that contains a neutron and a proton. The atom is called deuterium, and the nucleus which exists in it is called a deuteron. It is one of the two stable isotopes of hydrogen. It is a stable particle due to the presence of the same number of neutrons and protons. Because of which, deuterium is positively charged. The free neutron of the deuterium atom is unstable and hence it usually undergoes beta decay with a half-life period of around 10.3 minutes.

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Binding energy is defined as the amount of energy needed to split a particle from a system of particles or to disperse the entire particles of the system. The binding energy of deuteron is approximately equal to 2.2 MeV. During the process of beta decay, change in energy occurs inside the atom. If the free neutron of the deuterium undergoes beta decay to form a proton, an electron, and an antineutrino, the total mass-energy of the constituent particles will be:

2(938.27 MeV) + 0.511 MeV = 1877.05 MeV

However, the energy of a deuteron particle is 1875.6 MeV, which means that it is stable against beta decay in terms of energy. During beta decay, the free neutron produces energy of 0.78 MeV, but the deuteron that has the binding energy of 2.2 MeV prevents the decay of the neutrons.

Deuterium Explained

Deuterium or hydrogen-2, symbol D, is also known as heavy hydrogen. There are two stable isotopes of hydrogen; one is protium or hydrogen-1 and the other is deuterium or hydrogen-2. The nucleus of deuterium is called a deuteron which contains a proton and a neutron, whereas the protium doesn’t contain any neutron in its nucleus. Deuterium is abundantly available in the oceans, one deuterium atom is found per 6420 atoms of hydrogen.

Did You know?

The stability of the deuterium atom has played a major role during the formation of the universe in the initial stage. In the Big Bang model it is assumed that the number of protons and neutrons are equal. In the early stages the available energies were much higher as compared to 0.78 MeV required to convert an electron and a proton into a neutron. When the temperature dropped, the neutrons were no longer generated from the protons. The decay of neutrons gradually decreased the number of neutrons. The neutrons which combined with the protons and formed the deuteron didn’t undergo any further decay. If all the neutrons had decayed, the universe wouldn’t be as we know it.

Deuteron Mass and Charge

Deuterium is a stable atomic particle containing a proton and neutron. It is denoted by D or 2H and is called Hydrogen-2. Mass of deuteron is expressed in terms of an atomic mass unit (amu) or electron volts (eV). The Charge of deuteron is +1e. This is due to the presence of protons.

1 Amu in Mev

The atomic mass unit (amu) is defined as the 1/12 mass of a carbon-12 atom. The carbon-12 or C-12 atom consists of 6 neutrons and 6 protons in its nucleus. Precisely, one amu is the average mass proton and neutron at rest.

If we want to convert the binding energy in terms of MeV (mega electron volt) per nucleon, will have to apply the conversion factor which is given by

1 MeV = 1.602 x 10-13 J

One amu is equivalent to energy of 931.5 MeV.

Amu Value

One AMU is the average of the rest mass of a neutron and the rest mass of a proton. This mass is approximately equal to 1.67377 x 10-27 kilogram (kg), or 1.67377 x 10-24 gram (g). The mass of an atomic particle in terms of amu is approximately equal to the number of protons and neutrons in its nucleus.

MeV Meaning

MeV is the abbreviation for mega- electron volt, and mev is the abbreviation for million electron volts.

A MeV or Mega electron-volt is 1 million times of an eV. One eV (electron-volt) is defined as the energy gained by an electron (or any other charged particle having a charge equal to that of an electron) when it passes through a potential difference of 1 volt. In SI unit 1eV is equal to 1.6*10-19 Joules.

Mass of a Deuteron

The exact formula applied to determine the mass of a deuteron is through atomic mass unit or mass electron volt is as follows:

To determine the mass of a deuteron, it is calculated by using the atomic mass unit (amu) or Mass electron volts (MeV). The one by twelfth part of the mass of a carbon 12 atom is defined as an atomic mass unit. Basically, there are equal amounts of neutrons and protons, six and six each, in the nucleus of the carbon 12 atom.

One atomic mass unit (amu) is the average of the proton and neutron rest mass. To calculate the atomic mass unit of any deuteron mass, the formula shown below is applicable to it. The equations differ with the amount of mass density in the atomic structure of the atom. Thus, the atomic mass value is defined in the following way.

The air conditioner and the refrigerator both work on the principles of heat sinks. Both the devices function to cool the temperature of a closed space while transferring the heat from a source which is usually the closed space to another place called a sink. This process consists of 4 thermodynamic stages which when combined together result in the transformation of electrical or mechanical energy into a thermal heat absorption system.

The working mechanisms of both the Air Conditioner and the Refrigerator involve the expansion of gases, adequately designed chemicals, and the conversion of gas to liquid. Also, there are several differences between air conditioning and refrigeration. Students will get more clarity about the concepts and differences between refrigeration and air conditioning by the table given below.

What are Air Conditioners and Refrigerators?

Air Conditioners are cooling devices that are generally used to cool large spaces like rooms or halls. The capacity of the air conditioner depends upon the requirement of the users and how much space does it need to cool. The AC is widely used now in almost every public utility space like conference halls, metros, trains and even buses. Temperatures soar to extreme levels during Indian summers and hence the AC have become an essential feature of all major events during this time period.  Domestic usage of AC during the summer season in homes is also very common. 

Refrigerators, on the other hand, are used to cool relatively small dimensions of space which are generally used for the preservation of food items and also in some cases medical equipment.  Refrigerators or fridges as they are more commonly known are an essential feature of every home as their usage for domestic purposes is very essential for a tropical country like India. Apart from homes, the fridge is also used in restaurants, storage of perishable food items and also for preserving medical items.

The Differences between a Refrigerator and AC in a Tabular Form

Earthing is a protection system for buildings through which all the electrical installations  are connected to the earth to prevent damage to the property and people due to any fault. This is achieved by driving conductive rods into the earth itself near where power enters the house. Connection to the ground also restricts the build-up of static electricity when handling flammable products or electrostatic-sensitive devices.

The purpose of earthing is to minimize the risk of incurring an electric shock on touching while there is a fault. Electrical circuits may be connected to earth (ground) for several reasons.

Earthing Serves as

• Personal protection

• Property/ operational protection

• Potential grading earthing

• Protection from electromagnetic pulses 

• Protection from lightning 

Why is Earthing Important?

Types of Earthing

The process of Earthing or electrical grounding can be done in various ways like wiring in factories, housing, other machines, and electrical equipment. There are different forms of earthing systems that are described below:

Plate Earthing System

In this type of system, a plate is made up of copper or galvanized iron that is placed vertically in the ground pit less than 3 meters from the earth. The electrode plate connects the electrical conductors to the earth. Moisture should be maintained around the plate earthing system for its better functioning.

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Pipe Earthing System

A galvanized steel-based pipe when positioned vertically inside a wet surface. Such a type of earthing system is known as pipe earthing. It is the most common type of earthing system used in houses. The pipe size mainly relies on the type of soil and the magnitude of the current.

Basically, for ordinary soil, the pipe dimension should be 1.5 inches in diameter and 9 feet in length and for rocky or dry soil, the pipe diameter should be greater than the ordinary soil pipe. The soil moisture decides the pipe’s length that is to be placed in the earth. 

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Rod Earthing System

Earth rods are made from copper and stainless steel or copper bonded steel. The best choice is copper bonded steel due to its combination of strength, resistance to corrosion, and lower cost. 

Their fittings are used to render the interface to the ground in all soil conditions in order to achieve satisfactory earthing systems. It deviates an electric current that might escape from a device to a metallic cable that ends with a rod buried in the ground.

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What is Grounding?

The grounding is actually a backup pathway that provides an alternating route or path for the current to flow back to the ground if there is a fault in the wiring system.

Difference between Earthing and Grounding

How to Prepare for Exams with this Topic?

Exam preparation is not complete without . One simply needs to register with or download the app. At one can find notes and other practice questions with solutions that are some of the best resources available to ace exams. The learning resources provide a thorough understanding of the topic.

A wave that generally is a disturbance that propagates the energy from one place to another without transporting any matter. For example,  stone hitting the surface of the water creates ripples that travel in a shape of concentric circles with its radius increasing until they strike the boundary of the pond. 

The brand new way to categorize waves is on the basis of the direction of movement of the individual particles of the medium which are basically relative to the direction that the waves travel. Here, we will discover more about the waves and their formats. The waves categorised on this basis leads to three notable categories that are the transverse waves and then the longitudinal waves and third is the surface waves.

• In a longitudinal wave, the medium or we can say that the channel moves in the direction which is the same with respect to the wave. Here we can say that the movement of the particles is from left to right and forces other particles to vibrate.

• In a wave which is transverse, the medium or we can say that the channel moves perpendicular to the direction of the wave. Here we can say that the particles move down and up as the waves move horizontally.

Difference Between Longitudinal Wave and Transverse Wave

A transverse wave is a wave in which particles of the medium move in a direction which is perpendicular to the direction that the wave moves. Suppose that we see a slinky that is stretched out in a horizontal direction across the classroom and a pulse is introduced into the slinky which is on the left end by vibrating the first coil down and up. The energy will begin to be transported through the slinky from the direction which is from left to right. As the energy is said to be transported from left to right we can see that the individual coils of the medium will be displaced upwards and downwards. In this case, the particles of the medium move in a direction which is perpendicular to the direction that the pulse moves. This type of wave is a transverse wave. 

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A wave which is said to be a longitudinal wave is a wave in which particles of the medium move in a direction which is parallel to the direction that the wave moves. In this case, the particles which are of the medium move parallel to the direction that the pulse moves. This type of wave is a longitudinal wave. The longitudinal waves are always said to be characterized by particles that are in motion parallel to wave motion. 

The speaker to the ear of a listener – the particles of air vibrate back and forth in the same direction and then we can say that in the direction which is opposite of energy transport. Each individual particle pushes on its neighbouring particle so as to push it forward. The collision of particle 1 with its neighbour serves to restore particle 1 to its position which is original and displace particle 2 in a direction which is forward. 

Longitudinal waves can always be quickly identified by the presence of such regions. This whole process continues along the particle chain until the waves of sound that reach the ear of the listener. 

Propagation of Longitudinal and Transverse Waves

The waves travelling through a medium which is solid can be either a wave which is transverse or longitudinal waves. Yet the waves that are travelling through the bulk of a fluid that is such as a gas or a liquid are always longitudinal waves. The waves which are transverse require relatively a medium which is rigid in order to transmit their own energy.

In a longitudinal wave propagation, one particle generally begins to move must be able to exert a pull on its nearest neighbour. If we notice here, the medium is not rigid as is the case with fluids, that is the particles will slide past each other. This sliding action is the characteristic of liquids and gases that generally prevents one particle from displacing its neighbour in a direction which is perpendicular to the energy transport. It is for this reason that only the waves which are longitudinal are observed moving through the bulk of liquids such as our oceans. 

The earthquakes or disasters are capable of producing both transverse and longitudinal waves that travel through the solid structures of the Earth. When the seismologists began to study the disaster or earthquake waves they noticed that only longitudinal waves were capable of travelling through the core of the Earth. For this reason, geologists believe that the earth’s core that basically consists of a liquid that is most likely molten iron.

We often find the terms speed and velocity as similar; however, practically, there’s a difference between them in terms of nature.

Let’s suppose I travelled 120 km in 5 hr, so obviously, my speed will be distance/time, i.e., 120/5 or 24 kmph. So this was the case for the speed, now if I ask which directions I took in my journey and from starting, in the middle, or while making turns and till the end, was my speed the same?  The answer will be clearly No; it’s because initially, the speed was 0 when my car was at rest when I started, it was slow, I also increased my speed, also decreased during the turns; on the whole, my speed wasn’t the same, which means I travelled with a velocity (varying speed) to cover 120 km distance in 5 hrs.

Overview of Speed and Velocity

Speed is defined as the distance travelled by an object in a unit of time. It doesn’t consider the direction of the object, i.e., it has only magnitude. This is how speed is called a scalar quantity. 

However, talking about velocity, velocity is defined as the rate of change of displacement. It is a vector quantity.

For example, I am planning to ride my vehicle on the hills of Himachal Pradesh at 65 kmph and on another trip, I plan to ride the same vehicle at 75 kmph in the West of Manali.

So, what difference do you find in both the trips?

Is it because of value or something else? Well! This page will help you acknowledge the difference in both the scenarios and also, why we consider speed and velocity as different parameters in Physics.

We often find the terms speed and velocity as similar; however, practically, there’s a difference between them in terms of nature. Here, we will look at some of the differences in speed and velocity in tabular form.

About Speed and its Types

Speed: According to Galileo, speed is defined as the distance covered per unit of time. For example, a man moving by car will cover a large distance as compared to a man moving by bicycle in the same time period. This is because a car can travel with more speed as compared to a bicycle. Speed is the magnitude part of the velocity in kinematics, thus it is a scalar quantity.

Speed = Distance/time

Its SI unit is metres per second. m/ s.

Instantaneous Speed: Instantaneous speed is the speed at any instant. For example, instantaneous speed can be seen on the speedometer of any vehicle. In mathematical terms, it is defined as the magnitude of the instantaneous velocity that is the derivative of the position concerning time. 

V=|v|= |dr/dt|

Average Speed: It is different from the instantaneous speed; average speed is the total distance travelled in a particular interval of time. In other words, the total covered distance divided by the total time interval is the average speed of the body.

  

Rotational Speed: It is a rotating speed. In other words, the rotational speed is the number of turns made by a body in unit time.

  

Tangential Speed: It is defined as the linear speed of a body travelling along a circular path. Mathematically, 

Tangential Speed= rotational speed x radial distance 

v = rω

Thus, tangential speed will be directly proportional to r when all parts of a system 

simultaneously have the same, as for a wheel, disk, or rigid wand.

Relative Speed: It is clear from its name that the speed of any body is relative to any other body that the speed of a body can be seen with reference to another body.

 

There are Two Types of Speed: 

Uniform Speed: When the distance travelled by a body is equal in equal interval of time then the speed is uniform. 

Non-uniform Speed: When the distance travelled by a body is unequal in an equal interval of time then the speed is known as non- uniform speed.

 

Velocity: Velocity is a physical vector quantity. It has a magnitude as well as direction. In calculus, velocity is the first derivative of the position with respect to time. Velocity, in other words, is the rate of change in the position of the body with reference to time. Its SI unit is metres per second. 

Velocity = displacement/time = (final position – initial position)/time

Relative Velocity: It is fundamental in both classical and physical physics. Relative velocity is a measurement of velocity between two objects as determined in a single coordinate system. 

Types of Velocity

Constant Velocity: A velocity that does not change with the direction and speed and moves along a straight line is called constant velocity.

 

Changing Velocity: A velocity that changes with the speed and direction or changes either speed or direction is called changing velocity. This is also called acceleration. 

Instant (Instantaneous) Velocity: When at a particular time, speed and direction change, then that phenomenon is called instantaneous velocity.

 

Terminal Velocity: When gravity takes over an object and results in the falling down of the object towards the earth through the atmosphere, then the constant velocity attained by the object is called terminal velocity.  

Differences Between Speed and Velocity

Now, let us understand the difference between speed and velocity in detail.

Speed vs Velocity

From the above text, we see that in velocity, we have a term called displacement. Displacement is the vector whose length is the shortest distance from the initial to the final position of a point P undergoing motion.

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Here, we see that there are two directions from the initial to the final position, and we choose the shortest direction, which means the velocity at which the object moves makes velocity a vector quantity.

From our text, we understand that speed considers the magnitude, while velocity considers both magnitude and direction.

Distinguish Between Speed and Velocity

• Difference between distance and displacement- Distance, which is a scalar quantity deals with the total area covered by an object, whereas, a displacement which is a vector quantity deals with the change in the position of the object. The distance can never be zero, whereas, displacement can become zero)

Density vs Volume

If we compare any two quantities, let’s say smog and emulsion; a smog is something like a low-liquid cloud formed of air pollutants, and emulsions are formed of two immiscible liquids viz: milk, hair cream. However, these two have differences in terms of density vs volume and let’s discuss how.

See here smog can spread very easily, and that’s why it has a greater volume, but the density is less, while emulsion takes lesser volume as compared to smog; however, its density is greater. 

Difference Between Volume and Density

A volume is something that a solid, liquid, or gas occupies. 

We define volume as the three-dimensional space enclosed by a  surface. For example, a space that a substance or shape occupies or contains is the volume.

We numerically quantify a volume by using the SI derived unit, i.e., the cubic meter.

If we compare the two quantities such as butter (a mixture of liquid and solid also called  Gel) and a whipping cream that we apply over the cake, then in the solid-state they both seem to remain stuck in one place while heating these, butter spreads quicker than the cream. 

On using the parameter of thermodynamics is temperature. On raising the temperature, butter has more volume than whipping cream. On the other hand, there is one parameter to distinguish between any two quantities, and it is density. So, let’s understand this term. 

Difference Between Density and Volume

If we say there are two bowls, in which one contains dust particles and another comprises yellow paint. 

Now, let’s take a weighing machine and measure their weights, what do we observe?

Well! Paint would be heavier than dust particles because dust particles would occupy around the container they are kept, while paint would contain the shape it is placed in and also remain stuck in one place.

So, what do we infer from the above statement?

See here the paint is denser than dust particles and that’s why we can say that density is the ability of a compound sticking at one place or something like solidness in itself.

Now, considering examples of comparison of the following quantities:

Whipping cream and the wall paint has more density but less volume; however, on the other hand, butter and dust particles occupy a large volume but less density.

There is one more difference that comes between two physical quantities and that is mass volume and density, so let’s understand what is the difference between density and mass volume in terms of mathematics.

What is the Difference Between Mass Volume and Density?  

From the above context, we clearly understand the inverse relationship of volume with the density; however, Physics relies more on mathematics and for this relationship also we have an equation and that is given by:

ρ = [frac{m}{V}]

Here, 

ρ = Density and it is measured in Kgm[^{-3}]

m = Mass and it is measured in Kg

V = Volume and it is measured in m[^{3}]

We can see that the volume of any quantity varies inversely with its density that we discussed in the above examples. 

There is one more thing and that is mass. So in the comparing example of butter and whipping cream, if we compare their masses by placing on a weighing scale, we observe that whipping cream measures more than the butter but spreads lesser than butter.

So, comparing on the basis of mass, volume, and density:

So, from the above table, we can easily find one more relation that a quantity bearing higher density also carries a larger mass but lesser volume. 

Here, density varies directly with the mass of the quantity but varies inversely with its volume.

Difference Between Mass and Volume

• Mass of a quantity does not depend on the state of matter viz: solid, liquid, gas, plasma,  or a Bose-Einstein Condensate (the fifth state of matter) but volume may change accordingly. 

• Mass can convert into another form while undergoing a chemical reaction, which is the law of conservation of mass in Chemistry; however, it is an impossible thing to do with volume.

• In mechanics, mass is a fundamental property that has a dimension of [M], while volume is a derived physical quantity and its dimension is also derived from some other quantity and that is the length. So, its dimension is [L[^{3}]].