Educational Wealth: physics

old papers: aiou ,3404,2011

Abdullah 0 3404, aiou, old papers, physics Wednesday, May 28, 2014

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 Old Papers</h2>
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Physics </h3>
 
 
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg631E3T38WKi1W79dg5QQuomT_lo3ySCSL2VeLMtINqVYHOsJ3lZz6tlQ4K2Qxy9Jk2bmGBrx8mAxXfhqiu_Ql67g3Wqqo90qVL5n63vRka_4zCgqdVyDcq_zllACNrBxwsMky59sa8k8/s1600/allama.png" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" loading="lazy" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg631E3T38WKi1W79dg5QQuomT_lo3ySCSL2VeLMtINqVYHOsJ3lZz6tlQ4K2Qxy9Jk2bmGBrx8mAxXfhqiu_Ql67g3Wqqo90qVL5n63vRka_4zCgqdVyDcq_zllACNrBxwsMky59sa8k8/s1600-rw/allama.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">AIOU</td></tr>
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            </h3>
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                     ALLMA IQBAL OPEN UNIVERSITY </h3>
Level Bachelor               Code : 3404            Semester Spring 2011 
Note: ATTEMPT ANY FIVE QUESTIONS .ALL CARRY  
            EQUAL MARKS 
 
Questions
#1 
     a) Calculate the electric field due to an electric dipole.  
     b) A molecule of water vapor causes an electric field in the  
         surrounding space as if it
 
were an electric dipole like that  
        of figure below. Its dipole moment has a magnitude  
        P = 6.2 x 1030cm.what is the magnitude of electric field at a  
       distance z =1.1 nm from the molecule on its dipole axis? 
Question #2                                                                              (20) 
Discuss Gauss’s Law and apply it on  
    i)     Cylindrical symmetry  
    ii)     Planar symmetry  
    iii)    Spherical symmetry.  
Question #3 
a)     Give a complete account on electric potential energy, calculate    
        potential due to an electric dipole?  
b)   The potential at the centre of a uniformly charged circular disk 
      of radius R = 3.5cm is Vo = 550V.  
i) What is the total charge q on the disk?  
ii) What is the potential at a point on the axis of the disk at a  
     distance z = 5 OR from the centre of the disk? 
 a) Discuss Ohm’s law in detail. Define electric current also.  
b)   One end of an aluminium wire whose diameter is 2.5mm is  
    welded to one end of a copper wire whose diameter is 1.88mm. 
    the composite wire carries a steady current i of 17 mA. 
    what is the current density in each wire?  
a) Calculate the field due to the current interaction of magnetic  
    field with current.  
b) Explain Biot Savart Law. 
a) Calculate the magnetic fields of a solenoid .Also calculate the  
    magnetic field of a toroid.  
b) What is thermo electrical seedback?  
a) What is Pelter’s and ThomsoB. effeet? Calcu!ate total EMF in     
    thermocouple.  
b) What is Faraday’s law of electromagnetic induction and  it's  
    differential from?  
a) Calculate power in alternating current circuits 
b) A series RLC circuit driven with £rms = 120V at frequency  
   fd = 60.0 Hz contains a resistance R=200 Ohm an iinductance with  
   Xl = 80.0 Ohm and  capacitance with Xc = 150 Ohm. 
i) What are the power factor cos ф and phase constant ф of the  
   circuits  
ii) What is the average rate Pav at which energy is dissipated  
     in the resistance. 
 
<h2 style="text-align: left;">
Old Papers</h2>
<h3 style="text-align: left;">
Physics </h3>
 
 
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg631E3T38WKi1W79dg5QQuomT_lo3ySCSL2VeLMtINqVYHOsJ3lZz6tlQ4K2Qxy9Jk2bmGBrx8mAxXfhqiu_Ql67g3Wqqo90qVL5n63vRka_4zCgqdVyDcq_zllACNrBxwsMky59sa8k8/s1600/allama.png" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" loading="lazy" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg631E3T38WKi1W79dg5QQuomT_lo3ySCSL2VeLMtINqVYHOsJ3lZz6tlQ4K2Qxy9Jk2bmGBrx8mAxXfhqiu_Ql67g3Wqqo90qVL5n63vRka_4zCgqdVyDcq_zllACNrBxwsMky59sa8k8/s1600-rw/allama.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">AIOU</td></tr>
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            </h3>
<h3 style="text-align: left;">
                     ALLMA IQBAL OPEN UNIVERSITY </h3>
Level Bachelor               Code : 3404            Semester Autum 2011 
Note: ATTEMPT ANY FIVE QUESTIONS .ALL CARRY  
            EQUAL MARKS  
 
Q 1. a) Describe Coulomb’s law and its gravitational law. What  
             are the differences between both laws?  
          b) A particle of charge -q, is located at the origin of an x-axis  
              at what location should a second particle of charge -4qi be  
              placed so that the net electric field of two particles is zero  
              at x = 3.0mm.                                                              [10]  
Q2.a) Define and explain the flux of an  
              electric field. [10]
b) A Gaussian surface in the form of a  
               cylinder of radius R is immersed in a uniform electric  
               field E. with the Cylinder axis parallel to the field .What  
               is the flux cp of the electric field through this closed  
               surface.  
Q3.a)     Describe scries RLC circuit and derive the expression for  
              e.m.f. developed across each component and the impedance  
              of the circuit. C \
b) Define resonance frequency and derive   
              the expression 
Q4. a)  Explain the relationship between the current and voltage  
       b)  Write Biot Savarfs Law   
Q5.     Analyze tlhe travelling electromagnetic wave quantitatively  
           and qualitatively.  
Q 6. 
     a) Explain the diamagnetic, paramagnetic and fciTOtbagmitic 
           behavior in matter,  
     b) Explain hysteresis curve and its practical application.  
Q7. Write note on any two of the following. 
i)  Faraday's law 
ii) Mutual Induction  
iii)  Ampere's law  
Q:8  
(a)  Derive the expression for field build up due to solenoid  
       and toroid  
b) Why magnetization vector "M' lags behind magnetic intensity  
      vector ‘H’? Expalin.
</div>

old papers: aiou ,3404,2011

Old Papers Physics AIOU ALLMA IQBAL OPEN UNIVERSITY Level Bachelor ...

Matter

Abdullah 0 Article, physics Tuesday, January 07, 2014

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<h3>
Volume  of matter</h3>
The space occupied by a substance is called its volume. 
<h3 style="text-align: left;">
solids </h3>
  Solids have definite shape and occupy definite space. 
Your , table, chair, a plant or an animal are solids
.
Some solids can be poured e.g. sugar, salt and flour are all solids in 
this case. Each particie of solid keeps the same shape and occupies the 
same space 
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Liquids </h3>
 Liquids do not have any shape.

Instead they take the shape of the information container. However, liquids can be poured occupy definite space. Water, milk  
<h3 style="text-align: left;">
Gases </h3>
Gases do not have any shape and do

not occupy definite space e.g. air.  
<h3>
Arrangement of Particles  in matter</h3>
 In each state, the arrangement of particles of matter is very different. That is why, all states of matter have different properties. In the following paragraphs, you will see how the different arrangements of parties give different properties to solids, liquids, You know that anything which occupies space and has mass, called matter. You are also of the three states of matter. solids, liquids and gases of objects. You and your class fellows are sitting on chairs in your classroom. You are reading your books. Your bags and notebooks are kept in desks. Your teacher is writing on the blackboard. There are different kinds of pictures on the wall. Some indoor plants are placed at the corner of the room. There is a glass water at your teacher's table. All these objects and so many others are different forms of matter. Even the air around you is a form of matter.

The space occupied by substance is cailed its volume. 
 
<h3>
 Arrangement of particles in a liquid </h3>
The particles in a liquid are apart from each other, but are still held together. So the liquids occupy a definite space and cannot be compresed.

Unlike solids, the particles of a liquid are not fixed in regular posiions id they move short distances. That is why, a liquid has no definite shape.
Particles in a Gas

characteristics:

They are far apart.

They are arranged in irregular way.

They move quickly in all directions.

There are very weak forces of attractions among them.  
<h3>
Arrangement of particles in a gas</h3>
<h4>
 Ice melts into water</h4>
 Robert Hooke was an English scientist. In .1678, he explained the properties of different states of matter. He was the first who told that when we heat matter, it expands. He also discovered that air is made up of particles separated from each other by large spaces. 
<h3>
 Freezing of liquid</h3>
 Change of a liquid into a solid

Its particles loose energy. They start moving slowly.

The particles lose more and more energy and come closer to each other. Then they get closely packed and are in fixed positions.

You know ice cream is made by freezing milk. Air is the most important part in ice cream as it is needed to keep the ice cream soft. 
<h3>
 Boiling: </h3>
Change of a liquid into a gas What happens when you heata liquid?

Its particles gain energy. They start moving faster.

You know which state of matter has this type of particles arrangement. Yes! the liquid has changed into a solid. This process is called freezing. 
<h3>
 What happens when you continue heating? </h3>
The particles become free from one another. They move quickly in all directions. Now they are irregularly arranged and are far apart.

You know these are the characteristics of the particles of a gas.

Yes! the liquid has changed into gas state. The process by which a liquid gets heat and changes to gas is called boiling. Many liquids can be changed into gases when we boil them with different amounts of heat.

You know that tap water contains many disease causing microorganisms. Boiling water is the best way of killing all microorganisms present in water.  
<h3>
Evaporation:</h3>
 All particles of a liquid do not move with the same speed. Some particles have more energy than the others. The high energy particles come to the surface of liquid and then escape from there. They move into air, as a gas.

Evaporation is the process by which a liquid changes into gas at a temperature which is below the <a href="http://educational-wealth.blogspot.com/2014/02/temprature-of-earth.html" target="_blank">temperature</a> at which it boils. If you leave water in a pan, it evaporates until no water is left there.  
<h3>
 Surface of liquid </h3>
 Low energy particles remain as liquid

High energy particles escape from surface

Evaporation occurs only at the surface of liquid while boiling occurs in the whole liquid. Evaporation occurs at all temperatures but if we provide heat to a liquid, its evaporation becomes fast.  
<h3>
Condensation: </h3>
 Condensation is the process by which a gas (vapours) changes into a liquid, by the effect of cooling. If we cool water vapours (a gas), they are converted into water (a liquid) again. This is an example of condensation.

From what small drops of water on the outer walls of cold water bottle come.

There are many water vapours in air (in the form of moisture). When these vapours touch the cold walls of bottle, they change into liquid water. This water makes small drops on the walls of bottle.

We use natural gas in our homes in its gas state. When we take it to other countries by ocean, it is converted to liquid state (called liquid natural gas: LNG) to save space. </div>

Matter

Volume of matter The space occupied by a substance is called its volume. solids Solids have definite shape and occupy definite spa...

Safe use of electricity in Homes

Abdullah 0 Article, physics Saturday, January 04, 2014

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Safe Use</h3>
 In a city the electric energy is distributed to various house and factories from a power station, by means of two wires (usually). One wire is earthed at power station. Its electrical potential is zero. Its is called “neutral wire”. The tester shows no glow at this wire. The electric potential of the other wire changes sinusoidally . This wire is called “live wire” and tester shows glow at this wire.

Human body is conducting, so electric current can pass through it. 
 How a person may be electrocuted  
When person touches the live wire, then potential difference is created between touching point of body and feet of the person (on earth). Due to which electric current flows through body of the person. This is how a person may be electrocuted; it may prove fatal for him. To avoid this the supply lines, in houses are covered with insulating material.

“An insulation covered wire is called cable”.  
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Why a cable be dangerous</h3>
 Due to heavy current the cable is heated up and its insulating cover is burnt, and it becomes dangerous.

The electric wiring in houses is made such that each household appliance is connected in parallel to the supplied voltage. In figure below a typical electrical circuit is shown. Each appliance has a switch which can be made ON or OFF. When switch is made ON then current passes through the appliance and when it is made off, then no current passes through it. The switch gets heated if electric current exceeds the rated, value. Hence it should be ascertained that maximum current that would pass through the switch is within its rated value. It is dangerous to connect the electrical appliance directed between live and neutral wires. This should be avoided.

The connections should be made through sockets and plug.  
<h3 style="text-align: left;">
Fuse wire</h3>
A small wire connected in series with the live wire. It is known as fuse wire of Fuse.

To avoid damage to an electrical appliance or to an electric circuit a thin wire of low melting point conductor is connected in series with live wire. It is known as fuse wire(or fuse).

When electric current exceeds the limit of rated value, then the fuse wire is heated up due to dissipation of electrical energy into heat. And temperature of fuse wire goes to its melting point. This results the fuse wire to fuse or melt. Due to which this wire breaks and the electric circuit automatically breaks. This avoids heavy damage of electric circuit or of electrical appliance.

“Never use thick fuse wire of conductor of high melting point”.

The fuse wire is useful when electric circuit becomes short due to some fault in it.  
Let us suppose that we want to insert a fuse along with air conditioner or heater of power 30000 W. If voltage supplied is equal to 240 V, then according to the available fuses in the market are usually rating 5A, 10A, 13A, 30A etc. Hence suitable fuse for the above is of 13A . 
<h3>
Circuit breaker </h3>
 A safety device used in place of fuse is called “Circuit breaker”. It breaks the electric circuit if current increases beyond the given rating.

Due to any fault or by switching many appliances simultaneously the value of current may increase the rating value (It may be due to sudden decrease (fluctuation) of voltages. Then the switch of circuit breaker becomes OFF automatically (moves down) due to which circuit breaks and flow of current is stopped. After removing the fault in the circuit, the switch of the circuit breaker is again made ON manually.

connected to earth in the house.  
Such an electric circuit has three wires  
(1) live wire  
(2) neutral wire 
 (3) earth wire. This circuit requires three-pin socket, and three-pin plug.

So that circuit breaks down. This avoids electric shock to the person touching the metal casing of electrical appliance.

A circuit breaker has a coil in which electric current flows when circuit is ON. This coil behaves like electromagnet. The strength of this electromagnet depends upon the value of electric current passing through it. When current exceeds a limit (rating value), the magnetic force of attraction is increased so much that it becomes able to attract the iron strip “A”; and its contact with the electric circuit is broken. It makes the electric circuit OFF. If the current flowing in the circuit (and hence in the coil of circuit breaker) remains within rating value then iron strip . 
A remains in position due to low attractive force of electromagnet and circuit remains ON. 
Most of electrical appliances like electric iron, electric kettle, refrigerators and motor pump motors, etc are such that their outer part is made up of conducting material. This part must be separated from the electric circuit inside. So that no current can flow through the outer part.  
<h3 style="text-align: left;">
Earth wire </h3>
Sometime between, due to some fault, this insulation between outer body and the inner circuit is damaged. Then it is quite dangerous to touch the outer body of the appliance.It may result in electric shock.

In order to avoid this risk an additional wire is used, along with live wire, and neutral wire. This is known as “earth wire”. Its one end is directly connected to earth in the house. Such an electric circuit has three wires  
(1) live wire 
 (2) neutral wire  
(3) earth wire.  
This circuit requires three-pin socket, and three-pin plug.

When ever metal conducting casing of electrical appliance gets connected to the live wire, then due to short circuit large current flows to the ground (earth) and causes the fuse wire to become hot and ultimately fuse or melt So that circuit breaks down. This avoids electric shock to the person touching the metal casing of electrical appliance.

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Safe use of electricity in Homes

Safe Use In a city the electric energy is distributed to various house and factories from a power station, by means of two wires (usuall...

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old papers: aiou ,3404,2011

Matter

Safe use of electricity in Homes

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