Question – 02
(A) On 7th April 2012, an Avalanche hit a Pakistan military base in the Gayari sector trapping 140 soldiers and civilians under deep snow. What is Avalanche; describe its four types with a focus on the most dangerous type?
Answer:
Define Avalanche:
Sliding down large or small size ice pieces due to gravity from snow-capped mountains or hills is called an avalanche. It usually takes place in the winter or spring season. However, the glacier movements may cause avalanches at any time. The primary causes of it are snowfall, metaphoric changes in snowpack, earthquakes, and rain.
Types of Avalanche:
There are four types of Avalanches.
1- Loose Snow Avalanche
Such avalanches originate from a single point from where they spread downhill in an inverted ‘V’ pattern, collecting more snow. They are common on steep slopes and are seen after a fresh snowfall, thus are not very solid.
2- Slab Avalanche: The Most Dangerous Avalanche
Slab avalanches occur when a large block of ice falls down a slope. This happens when the weak layers of ice lying lower down in the snowpack are triggered; it falls down pulling all the layers on the top like a giant slab of snow.
Why are Slab Avalanches so Dangerous
a. Slab avalanches account for around 90% of avalanche-related fatalities in the countries.
b. They reach a high speed in a very short period of time. Even small slab avalanches are capable of destroying forests and small villages in the area.
c. They have a distinct fracture line. If there is a bonded layer of snow (the slab) on top of a weak layer, they occur.
3- Wet Snow Avalanche
Wet snow avalanches are comprised of snow and water at the beginning. Due to friction, they travel slowly but can pick up speed with ease. They are powerful and can scour boulders, earth, trees, and other vegetation, leaving exposed and often scored ground in the avalanche track.
4- Powder Snow Avalanche
A combination of loose snow and slab avalanches is termed a powder snow avalanche. The bottom half consists of a slab, ice, and air; while the upper half has a cloud of powdered snow. The speed attained by it can cross 190 miles per hour.
(B) What do you understand by Global Wind and Pressure patterns? Also, explain wind and pressure features at higher altitudes.
Wind:
The natural movement of air or other gases relative to a planet’s surface is caused by differences in air pressure within our atmosphere-from high-pressure areas to low-pressure areas.
Global Wind Patterns:
Based on the uneven heating of the Earth’s surface-The warm temperature at the equator and cold temperature at the poles, there are four major types of global wind systems.
1- Polar Easterlies:
Polar Easterlies are cold and dry because they are located at high latitudes of 60-90 degrees in the southern and northern hemispheres. They blow from high-pressure areas of polar highs towards low-pressure areas- that is, sink towards the equator.
2- Prevailing Westerlies:
Prevailing Westerlies blow from west to east. They are located at 30-60 degrees latitude in the northern and southern hemispheres. These are steady winds that blow from the high-pressure area in the horse latitude- Regions located at about 30 degrees north and south of the equator- toward the poles
3- Tropical Easterlies:
Tropical Easterlies are located at 0-30 degrees latitude in both hemispheres. They flow from east to west due to the Coriolis Effect- the deviation of wind direction due to the rotation of the earth. The warmer air rises up from the equator and sinks back when it cools down.
4- Inter-tropical Convergence Zone (ITCZ):
Intertropical Convergence Zone- also called Equatorial Convergence Zone- is an area near the equator where the easterly trade winds of both hemispheres converge producing a narrow band of clouds and thunderstorms. The storms are short; however, aI large amount of rain I produced from them.
Pressure:
The weight of the column of air above a particular location per unit area is called Air Pressure.
Global Pressure Patterns:
Following are the four pressure belts of the earth’s globe
1- Equatorial Low-Pressure Belts:
An equatorial low-pressure belt exists between 0 to 5 degrees north and south of the Equator. It is called doldrums because there is little and no wind in this belt. It is very hot since sun rays direct hit the region, and the warm air from the equator rises up causing low pressure to develop here.
2- Subtropical High-Pressure Belts:
Subtropical high-pressure belts lie between 30 to 35 degrees North and South of the Equator. The weather is warm and moderate with stable and calm winds. Here, the pressure is high because the air gets cool in the Subtropical region.
3- Sub-polar Low-Pressure Belts:
Sub-polar low-pressure belts exist at about 45 to 60 degrees North and South of the Equator. They are associated with the polar front; thus, the temperature here is low making the zone less distinguishable. Moreover, it is the belt where extratropical cyclonic storms are produced.
4- Polar High-Pressure Belts:
Polar high-pressure belts exist at about 70 to 90 degrees North and South of the Equator-the small region extending to the poles. Here, the cold descending air gives rise to high pressures over the Poles.
Winds and Pressure Features at High Altitudes:
The atmospheric pressure and altitude are inversely proportional to each other. As the altitude-the distance above sea level- rises, air pressure drops because of two reasons: earth’s gravity and density (the air at heights becomes less dense than air nearer to sea level). Further, the less dense air at higher altitudes makes the wind more powerful with the high speed of air particles.
(C) World’s largest earthquake was assigned a magnitude of 9.5 by the United States Geological Survey on 22 May 1960 in southern Chile Valdivia. What do you know about earthquakes? Also, explain shallow-focus and deep-focus earthquakes.
Answer:
Earthquake:
Intense shaking and trembling of the Earth’s surface caused by sudden forces or movements in its outermost layer are known as an earthquake, a natural disaster.
Formation of Earthquake:
When stress in the crust, the outermost layer of the earth, exceeds the strength of the rock, it breaks along the lines of weakness, either a pre-existing or new fault plane.
1- The starting point of an earthquake is termed the hypocenter or focus may maybe hundreds of meters deep within the earth.
2- Similarly, the point at the earth’s surface directly above the focus is called the earthquake epicentre.
Causes of Earthquake:
The most common causes of earthquakes are
1- Fault zones
2- Plate tectonics
3- Volcanic activity
4- Human activities.
Measurement of earthquake:
Since earthquake is exhibited in the form of seismic waves, experts use seismometers to record the seismic waves produced by earthquakes.
Shallow Focus and Deep Focus Earthquakes:
Shallow-Focus Earthquakes:
1- Earthquakes that occur anywhere less than 70 kilometres from the Earth’s surface are called Shallow Focus Earthquakes.
2- They are called crustal earthquakes.
3- They occur quite frequently and at random.
4- The majority of such earthquakes are of smaller magnitude. Therefore, they are often not felt.
5- Though smaller in magnitude, shallow-focus earthquakes pose a greater threat at the surface, as all energy is directed towards a small area.
Deep-Focus Earthquakes:
1- Earthquakes that are deeper than 70kilometerss from the earth’s surface are called deep-focus earthquakes
2- They are often triggered by the collision between plates, hence, they are also known as intraplate earthquakes.
3- They, usually, have high magnitudes like 6 or above.
4- deep-focus earthquakes do not cause much damage as the foci of the quakes to lie at great depths and the energy of the quakes dissipates over a wide area.
5- The strongest deep-focus earthquake ever recorded is of magnitude 8.3, whereas the deepest earthquake is 735.8 km.
(D) Differentiate between renewable and non-renewable energy sources. Briefly explain Geothermal Energy and Hydro Electricity.
Difference between renewable and non-renewable energy sources:
|
|
Renewable Energy |
Non- Renewable Energy |
|
Definition |
The sources of energy which on usage
can’t be lost forever, but can be recycled and replenished. |
The sources of energy which on used are lost forever, and can’t be recycled and replenished. |
|
Biodegradable renewable renewable |
Renewable energy sources are
eco-friendly and do not cause much pollution in the atmosphere. |
Non-renewable energy sources are not
eco-friendly and cause a lot of pollution in the atmosphere due to the
emission of excessive carbon. |
|
Reused and Recycled |
These energy sources can easily be
reused and recycled. |
One cannot reuse and recycle these
types of energy resources. |
|
Sustainability |
These resources are s ustainable. |
These energy resources are not
sustainable instead exhaustible. |
|
Cost |
The overall cost of these energy
sources is high. It required high capital to install and maintain these
sources of energy. |
The overall cost of these energy
sources is not very high, because they can be found naturally. |
|
Examples |
The five major sources of renewable
energy are; solar, wind, hydro, geothermal, nd biomas . |
The non-renewable resources are;
coal, nuclear elements, oil, natural gas, and fossil fuel. |
Geothermal Energy:
✓ Define:
Geothermal energy is a form of renewable energy in which hot water and steam underground the earth are used to drive the turbines to generate electricity.
✓ Occurrence:
Since geothermal energy is produced when the heat is absorbed by water and rocks coming from the highest temperature magma deep down the earth, it is primarily found along major tectonic plate boundaries where most volcanoes are located.
✓ Example:
One of the most active geothermal areas in the world is called the Ring of Fire, which encircles the Pacific Ocean
✓ Process:
To harness geothermal energy, a hydrothermal convection system is used. In this process, a hole is drilled deep under the earth, through which a pipe is inserted. The steam trapped in the rocks is routed through this pipe to the surface of the earth. This steam is then used to turn the blades of a turbine of an electric generator. In another method, the steam is used to heat water from an external source which is then used to rotate the turbine.
Hydro-Electricity:
✓ Define:
Hydroelectricity or hydropower is a source of renewable energy, which uses moving water to generate electricity.
✓ Occurrence:
Hydroelectricity is produced where water is freely available or where water can be utilized via dams. Tidal power is also considered a form of hydropower that is used to generate electricity by using tidal energy, but not widely in use.
✓ Example:
Three Gorges Dam is the biggest hydroelectric power plant in the world.
✓ Process:
For producing power by hydro plants there must be a water reservoir, dam, gate, or valve to control the flow of the water. Because the highest the head from where water flows, the higher potential energy water gains before flowing downwards. During the process of flowing from a higher point to downward water converted its high potential energy into kinetic energy. This water then hits the turbines, which are attached to a generator to produce power.
Question – 03
(A) What are Pesticides? Explain their different types; why persistent pesticides are more lethal for mankind?
Answer:
Pesticides:
A pesticide is used to control, repel, or kill certain forms of plant or animal life that are considered to be pests- destructive insect or other animals that attacks crops, food, livestock, etc.
Types of Pesticides:
Pesticides are grouped according to the types of pests which they kill:
Based on the types of Pests They Kill
- Insecticides – insects
- Herbicides – plants
- Rodenticides – rodents (rats & mice)
- Bactericides – bacteria
- Fungicides – fungi
- Larvicides – larvae
Based on how biodegradable they are:
• Biodegradable Pesticides:
Biodegradable pesticides are those kinds of pesticides which be broken down by microbes and other living beings into harmless compounds.
• Persistent Pesticides:
Persistent pesticides are those pesticides that may take months or years to break down.
Why are persistent pesticides more lethal for mankind?
Persistent pesticides are called persistent because they cannot be degraded by biological systems and environments. They finally reach humans from plants directly or from animals and cause damage to the nervous system, causing tingling, seizures, tremor, and numbness. Pesticides can accumulate in a person’s body over time, but the health effects associated with such exposure are not well defined. People who work with persistent pesticides for a long time have also shown biochemical changes consistent with liver injury.
(B) What are carbohydrates? Classify and give detail of each class along with examples.
Answer:
Carbohydrates:
Carbohydrates are organic compounds that contain carbon and hydrogen in them. They are also called ‘sugars’ and are the most abundant molecules on the surface of the earth.
General Formula:
Their empirical formula is Cx (H2O)y.
Formation:
Moreover, they are prepared by the photosynthesis process in plants.
6CO2+6H2 O → C6H12 O6+6O2
The process is taken place in the presence of sunlight and chlorophyll. Glucose is obtained as a byproduct.
Classification:
Carbohydrates are classified into three types.
1- Monosaccharides:
These are the simplest sugars that cannot be further hydrolyzed. They contain 3 to 9 carbon atoms. Hence, their classification is based on the number of carbon atoms e.g. trioses, tetroses, hexoses, pentoses etc.
For example:
Glucose and fructose are examples of Monosaccharides.
2- Oligosaccharides:
Oligosaccharides contain 2 to 9 units of Monosaccharides that can be further hydrolyzed. Hence, their classification is based on the number of units on hydrolysis e.g. disaccharides, trisaccharides, tetra-saccharides, etc.
For example:
Sucrose is an example of of oligosaccharides in the presence of dilute HCL and by providing the heat sucrose is converted into glucose and fructose on hydrolysis.
3- Polysaccharides:
Polysaccharides are macromolecules that consist of hundreds and thousands of monosaccharides.
For example:
Starch and cellulose are examples of polysaccharides.
(C) Discuss different methods of food preservation.
Answer:
Food Preservation:
Food preservation is the technique that is used to prevent food from spoilage, poisoning, and microbial contamination for a long time.
Methods of Food Preservation:
Some methods for the preservation of food are
1- Freezing:
In this method, the temperature of the food items is lowered by placing them in cold storage which helps in preventing the growth of micro-organisms, like bacteria and fungi. Fish is usually transported from Karachi to other cities by placing ice cubes in their storage.
2- Vacuum Packing:
In this method, food items are placed in a plastic bag. And the vacuum is created in the bag by removing the air containing oxygen and co2- the essential requirements for the growth of Bacteria. It results in the death of microorganisms. This method is usually used for the preservation of dry fruits- the best source of food for astronauts.
3- Salting:
The method implies the use of edible salt thrown over the food items. It, not only slowdowns the nourishment of Bacteria but also deactivates the enzyme present in the tissues. Meat in farsighted areas where there is no light and other techniques of preserving food is not applicable.
4- Canning and bottling:
In this method, the, already, cooked food items are restored in cans and bottles made sterile by burning or washing them with different sterling agents. The food items are safe till the cans and bottles are sealed. The partially cooked pulses are, usually, stored with the help of this method.
5- Burying in the ground:
Food items are buried in the ground with no light, oxygen, and Carbon dioxide. This hampers the growth of microorganisms. It is commonly used to preserve vegetables, like potatoes.
(D) Where and how Fiber Optics is used? Also, write down their advantages and disadvantages.
Answer:
Define:
Fibre optics is a bundle of thin strands made of glass or plastic, which uses light (photon particles) to transmit signals. Therefore, the transmission capacity of fiber optics is far greater than other modes of communication, such as copper wire and metallic wires. As a result, it is used in the form of different cables and is being utilized in numerous fields of life.
How does Fiber-Optics work?
The propagation of light in an optical fiber requires that light should be totally confined within the fibre and not escape from it. This can be done by
✓ Total internal reflection
✓ Continuous Refraction
Since light rays travel in straight lines, optical cables are designed in a way that they bend all the light rays inwards. Light rays travel continuously, bouncing off the optical fiber walls and transmitting end-to-end data. Although light signals do degrade over progressing distances, depending on the purity of the material used, the loss is much less compared to using metal cables.
Uses of Optical Fibres:
Following are a few uses of optical Fibre:
✓ Used for Telecommunication for transmitting and receiving purposes
✓ Used in medical devices to view internal body parts
✓ Used to transmit images
✓ Used in wirings in aircraft, hydrophones for SONARs, and seismic applications.
Advantages and Disadvantages of Optical Fibers
The advantages of optical fiber are as follows.
a. The bandwidth of optical fibers is higher than copper wires.
b. Optical fibers have fewer power losses, and data can be transmitted for much longer distances.
c. The optical fiber cables are resistant to electromagnetic interference.
d. Since the weight of optical fibre cables is less, their Installation is relatively easy.
e. Fibre optic cables are very flexible and oppose most acidic elements that hit the copper wire.
The disadvantages of optical fiber include
1. Optical fiber cables are expensive to install.
2. The optical fiber cables are very difficult to merge, and there will be a loss of the beam within the cable while scattering.
3. The Optical fiber cables require special test equipment before installation.
4. Since fiber optic cables are compact, they are more vulnerable than copper wires.
5. In optical fibers, transmission requires repeating at distant intervals.
Question – 04
(A) Briefly describe the various segments of the atmosphere. How these segments are maintaining the Earth Radiation Balance?
Answer:
What is Atmosphere?
The layers of gases around the earth are called the Atmosphere. In other words, an atmosphere contains the air that we breathe and is a blanket of gases that surrounds Earth. Moreover, it is held near the surface of the planet by Earth’s gravitational attraction.
Based on its temperature, the atmosphere can be categorized into 6 segments.
1- Troposphere:
The bottom-most layer of the atmosphere where we live is iisthe troposphere. It extends upward to about 10km above sea level starting from the ground level. It comprises 75% of all air in the atmosphere; its lowest part is known as the boundary layer while the topmost layer is called the tropopause.
2- Stratosphere:
Above the troposphere lies the stratosphere. Its distance from the surface of the earth is 12 -50 Km. The ozone layer lies in the stratosphere; the stratosphere is the layer where aeroplanes fly.
3- Mesosphere:
The layer of ions is Mesosphere. It extends to a height of about 85km from the ground level.
4- Thermosphere:
The topmost layer of the strata of the atmosphere is the thermosphere. Its distance from the earth’s surface is 80-320 Km. Satellites orbit Earth within the thermosphere.
5- Exosphere:
The pseudo or false atmosphere above 500 km is the exosphere. It is the final frontier of the Earth’s gaseous envelope. The exosphere is 10, 000 km from the earth’s surface. However, there’s no clear-cut upper boundary where it finally fades away from the space.
6- Ionosphere:
The ionosphere is an abundant layer of electrons and ionized atoms and molecules that stretches from about 48 kilometres (30 miles) above the surface to the edge of space at about 965 km (600 mi), overlapping the mesosphere and thermosphere. This region is what makes radio communications possible.
How these segments are maintaining Earth’s radiation balance?
To understand this part of the question, it is pertinent to first know what is meant by EartEarth'siation balance? The radiation balance of Earth is the algebraic sum of the incoming and outgoing components of radiation. The energy which is released as shortwave light and UV radiation from the Sun rereflectsack to space in a shorter portion as much of this energy is absorbed by the surface of Earth and some of it is absorbed in the clouds.
Moreover, the atmospheric segments (layers) play a crucial role in maintaining the heat balance on Earth because the ozone molecules present in the stratosphere absorb high-energy ultraviolet radiations (UVB & UVC) coming from the sun and they convert it into both atomic and diatomic oxygen. That is why the temperature starts increasing gradually in this layer with the increasing altitude. Also, atomic oxygen is found in a huge amount in the upper part of the stratosphere due to the breakdown of ultraviolet radiations and also the destruction of diatomic oxygen. It is when these two forms of oxygen recombine and form the ozone molecules, there releases a prevalent amount of heat because of which the temperature is high in this layer. In other words, it would be sound to say that the Earth is protected from UV rays and IR reradiation to the ozone layer present in the stratosphere.
(B) How the organic particulate matter enters the atmosphere. Also, describe the sources?
Answer:
Organic Particulate Matter:
Organic particulate matter is particulate matter that is composed of carbonaceous and other organic substances. It is basically a complex mixture of some liquid droplets present in the air, consisting of a variety of components such as metals, acids, and organic compounds. Organic particulate matter is a major cause of air pollution.
Sources of organic particulate matter:
1- Diesel engines
2- Wood smoke
3- Gasoline engines
4- Paved road dust
5- Gaseous precursors
How does it enter the atmosphere?
There are two ways in which organic particulate matter enters the atmosphere:
a. Direct way or Primary Source
b. Indirect way or Secondary Source
Primary source or direct way:
The organic particulates enter the atmosphere directly through:
✓ It directly emits carbonaceous compounds in the air and the organic particulate matter gets into the atmosphere.
✓ The release of certain gases from solid waste also results in the emission of organic matter into the atmosphere.
✓ The release of chlorofluorocarbons (CFCs) into the air
✓ The release of carbon dioxide (CO2),sulfurr dioxide (SO2), carbon monoxide (CO), and nitrogen oxide (NO2) in the air
Secondary Source or Indirect way:
The already suspended harmful gases and substances in the air when combined with each other or other air pollutants of organic nature they form organic particulate matter in the atmosphere. Moreover, the condensation of oxidation products of certain volatile organic compounds also forms organic particulates in the air.
For example:
✓ Acid Rain is a combination of CO2 and H2O forming carbonic compounds in the air.
✓ The formation of smog when smoke (having carbon particles) combines with fog.
✓ Volatile organic compounds are those compounds that catch fire and result in fumes. These fumes when combined with oxides of nitrogen, they release chemical compounds and molecules of ozone.
(C) What is natural radioactivity? How is it different from artificial radioactivity?
Answer:
Natural Radioactivity:
Certain substances are having unstable nuclei, called radioactive elements, such as uranium. It is a process in which the nucleus of an atom of radioactive elements undergoes spontaneous and uncontrollable disintegration (or decay) and emits alpha, beta, and gamma rays. The process of emitting these rays is called radioactivity of the elements and rays emitting are called radioactive rays. Therefore, natural radioactivity is the spontaneous disintegration of the nuclei of heavy (radioactive) elements with the emission of radiation.
Artificial Radioactivity:
Induced radioactivity, man-made or artificial radioactivity, is a process that converts stable elements to unstable elements by bombarding them with appropriate atomic projections like alpha, beta, and gamma.
Example: alpha = helium nucleus whose mass number is 4 and nuclear charge (atomic number) is +2.
|
Characteristics |
Natural radioactivity |
Artificial radioactivity |
|
Definition |
Nuclear reactions occur
spontaneously and emit radioactive rays, called natural radioactivity. |
It’s man-made radioactivity that is
used to convert stable elements to unstable elements by bombarding alpha beta
gamma rays. |
|
Reactants |
Single reactant |
Involve a chemical element and an
initiating particle |
|
Reactant type |
Fusion reaction |
Fission reaction |
|
Example |
Fusion in the core of the sun |
Fission in heavy machinery |
(D) What are the Fossils? Discuss the importance of paleontology.
Answer:
Fossils:
Fossils are the preserved remains, or traces of remains, of ancient organisms. Fossils are not the remains of the organism itself: they are rocks. A fossil can preserve an entire organism or just part of one. Bones, shells, feathers, and leaves can all become fossils.
Importance of Paleontology:
While many people write off palaeontology as just another branch of science, few realize its true significance.
a. The information provided by papaleontologistsan offer clues about the modern climate. This data may prove vital in the efforts to undo the damage caused by human actions.
b. Palaeontology helps us to track the changes to the ecosystems around us. Further, it helps us to better understand exactly what elements are changing in our ecosystems and what leads to those changes.
c. Conservation of modern life requires understanding the life forms of the past.
d. In fact, no other branch of science can offer the amount of data regarding change over time.
e. Palaeontology is foundational to dozens of other scientific fields. PPaleontologyis a gateway science.
f. Children that take an early interest in learning often go on to exhibit intellect later in life.
Question – 05
(A) What do you know about Hepatitis? Describe its types and write down preventive measures.
Answer:
Hepatitis:
Hepatitis refers to an inflammatory condition of the liver.
Causes of Hepatitis:
Primarily, it is a viral disease. However, sometimes medication, drugs, toxins, and alcohol are also responsible for autoimmune hepatitis-a disease that occurs when a human body makes antibodies against liver tissues.
Symptoms of Hepatitis:
Some of the common symptoms of hepatitis are fatigue, loss of appetite, high fever, nausea, vomiting, and, abdominal pain.
Types of Hepatitis
Hepatitis is mainly classified into five categories Hepatitis A, Hepatitis B, Hepatitis C, Hepatitis D, and Hepatitis E, among which the first three are better known.
1- Hepatitis A:
a. Hepatitis A was formerly called Infectious Hepatitis.
b. Hepatitis A is a mild viral liver disease caused by a non-enveloped RNA virus.
c. It is transmitted through ingestion of contaminated food and water or through direct contact with an infected person.
d. Its epidemics can be explosive and cause substantial human and economic loss.
e. Almost everyone infected with hepatitis A recovers fully with lifelong immunity. However, a very small proportion of hepatitis A patients die from it.
–Preventive Measures for Hepatitis A:
Vaccines for hepatitis A are available. Moreover, safe water supply, food safety, improved sanitation, and regular washing of ds are the most effective ways to combat the disease.
2- Hepatitis B:
a. Hepatitis B virus was formerly called serum Hepatitis.
b. Hepatitis B varies from acute to chronic liver disease and is caused by a DNA virus.
c. The virus is mostly transmitted to a person through contact with the blood or other body fluid of an infected person.
d. An estimated 240 million people are chronically infected with hepatitis B. More than 700,000 people die every year due to complications of hepatitis B. Besides, it also causes cirrhosis (liver fibrosis or dysfunctional liver) and liver cancer.
e. It is a major occupational hazard for health workers.
–Preventive Measures for Hepatitis B:
It can be prevented by currently available vaccines. Moreover, avoiding using syringes, safe sex practices, and implementing blood safety strategies can help in the prevention of Hepatitis B.
3- Hepatitis C:
a. Hepatitis C was formerly called non-A non-B Hepatitis.
b. Like hepatitis B, the hepatitis C virus is also an acute to chronic hepatitis infection caused by RNA enveloped virus.
c. It is a blood-borne disease that is mostly transmitted through unsafe injection practice, inadequate sterilization of medical equipment, the transfusion of unscreened blood and blood products, unsafe sex, and from an infected mother to her baby.
d. A significant number of those who are chronically infected will develop liver cirrhosis or liver cancer.
e. Globally, between 130-150million people, have chronic hepatitis C infection, and approximately 700,000 people die from hepatitis C-related liver diseases.
–Preventive Measures for Hepatitis C:
Currently, there is no vaccine available for hepatitis C. However, implementing blood safety strategies, such asaquality-assured-ureded screening of all donated blood, can help prevent the transmission of hepatitis C. Similarly, safe sex practices and proper disposal of used syringes can be effective strategies to protect against transmission.
(B) Differentiate between Middle Latitude Cyclones and Tornadoes.
Answer:
|
Characteristics |
Mid-latitude Cyclones |
Tornadoes |
|
Define |
Middle latitude cyclone is a type of
storm, formed in middle latitude, characterized by rapidly swirling air
masses around a low-pressure core, which results in stormy and often
destructive weather |
A tornado is a small but intense
vortex of a spinning column of air that extends between the earth’s surface
and a cloud. |
|
Formation |
Middle-latitude cyclones are the
result of the dynamic interaction of warm tropical and cold polar air masses
at the polar front. |
Tornadoes form when warm, humid air
collides with cold, dry air. |
|
Rotation |
Clockwise in the southern hemisphere
and counterclockwise in the northern hemisphere. |
It also has the same rotation in
both the hemispheres. |
|
Measuring Scale |
The scale for measuring
cyclones is called the Beaufort Scale and Saffir-Simpson scale. |
The scale used for rating the
strength of tornadoes is called the Fujita (F) and Enhanced Fujita (EF)
Scale. |
|
Circumference |
They have a wide circumference. |
They have a small circumference. |
|
Diameter |
Diameter 200km |
Diameter 300_400 yards |
|
Duration |
They last for 3 to 10 Days. |
They last for less than 10 minutes. |
(C) What is Open System Interconnections (OSI) and describe its layers?
Answer:
Open System Interconnections- OSI:
Open system interconnection is a reference model for how applications communicate over a network. The model focuses on providing a visual design of each communication layer built on top of the other, starting with the physical cabling, all the way to the application that’s trying to communicate with other devices on a network.
Layers of OSI:
According to the standard OSI Model, there are seven layers. Each layer is dependent upon the layers below it to function.
Layer 7: Application layer:
The application layer enables the user- human or software- to interact with the application or network whenever the user elects to read messages, transfer files or perform other network-related tasks. Web browsers and other internet-connected apps such as Outlook and Skype use Layer 7 application protocols.
Layer 6: Presentation layer:
The presentation layer is responsible for the proper translation to interpret a message sent through the network properly. The layer is also responsible for the encryption and decryption that the application layer requires.
Layer 5: Session layer:
The session layer is responsible for request or response communication. When required, a session is started with authentication, and then a request is sent. The response is a signal that the session might end, or a new request may be sent. This is the first layer where a client/server concept is introduced.
Layer 4: Transport layer
The Transport Layer ensures the reliability and quality of a system. The layer also controls traffic flow via the network layer and checks errors guaranteeing the quality of service by resending data after data has been corrupted.
Layer 3: Network layer
The Network Layer ensures the coordination of related parts of a data conversation so that large files can be transferred. Stating differently, the network layer organizes the data for transfer and reassembly that is transferred using the data link layer method. This layer also handles aspects of Routing Protocols, finding the available [best] path(s) from one network to another to ensure delivery of the data.
Layer 2: Data link layer
Data Layer the dadatainks information from the network to the physical layer by breaking data into frames. Some error detection and correction are also done in this layer.
Layer 1: Physical layer
The physical layer deals with the physical as well as an electal portion of devices that explains how a device sends or receives signals via copper wires or optical fibres. Additionally, the layer converts signals into a compatible form that the next layer can use-a bit- and adjusts them to allow multiple users to use the same connections.
For Example:
-Ethernet or fibfibertic cables
-Phone cords used for dial-up or DSL services
-Coaxial cable is used to provide broadband internet etc.
(D) What is GPS? How does it work?
Answer:
Global Positioning System:
Geo Positioning System, GPS, is a space-based navigation technology that provides the pinpoint location, velocity, and time-24 hours a day- of anything on the earth with ultra-high accuracy. Although the GPS project has been started by the US Defense Department in 1973 for military operations, it has not been in the mainstream until 2007.
Working of GPS:
Mainly, the GPS has three fundamental segments:
-Satellites
-Receivers
-Control systems
Almost 31 satellites orbit around the earth at different angles collecting data from all over the earth, they continuously emit radio signals. In response to the approaching signals, the portable receivers, for instance, your mobile phones become active and measure the time and location of the satellites. The distance is then measured by triangulation, tri referring to three, as three minimum satellites are always required to produce accurate signals. Meanwhile, the control systems are responsible for the proper functioning of the entire GPS by tracking, controlling, and communicating with the satellites.