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• Users: logearav
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1. ### Properties of electric lines of force

i understood about lines of force not traveling inside the conductor. but i can't understand lateral pressure and longitudinal contraction,sir? could u elaborate? also thanks for the reply.
2. ### Applications of Vandegraff generator

Homework Statement Vande Graff generator is used to generate potential difference to the order of 107 volts to accelerate charged particles. Homework Equations My question is, " Will this voltage can be used to accelerate electrons or it is merely confined to accelerating positive...
3. ### Properties of electric lines of force

Homework Statement my textbook mentions the following as properties of lines of forces among other things They do not pass through a conductor. They contract longitudinally. They exert a lateral pressure on each other. I want clarification on these points i) Why lines of force do...
4. ### Free electron gas model or classical theory

Homework Statement In Drude - Lorentz' FREE ELECTRON GAS MODEL , it has been said " since the conduction electrons move in a uniform electrostatic field of ion cores, their potential energy remains constant and is normally taken as zero, i.e., the existence of ion cores is ignored." I don't...
5. ### Conduction electrons?

Homework Statement Electrons present in the outermost orbit are valence electrons. If we supply sufficient energy to these electrons they make their transition from valence band to conduction band and electrons in conduction band are termed as conduction electrons. My question is, take for...
6. ### Photoelectric effect

Beautiful explanation mr. gogobeid. I got it now. Thanks a lot
7. ### Electric dipole in a uniform electric field

Mr. tiny-tim, thanks a lot for the explanation.
8. ### Electric dipole in a uniform electric field

Homework Statement An electric dipole placed in a uniform electric field experiences a torque which tends to align the dipole parallel to the field. At the same time, due to two equal and unlike parallel forces Eq and -Eq acting at q and -q, the net force is zero. When the net force is zero...
9. ### Photoelectric effect

Homework Statement Lenard's experiment on photoelectric effect concluded mvm2/2 = eVs where vm is the highest velocity of photo electrons and Vs is the stopping potential. From this he concluded maximum velocity of photo electrons depends only on the wavelength of light used and not on the...
10. ### Binding energy

Homework Statement the lesser amount of binding energy for lighter and heavier nuclei explains fusion and fission. It has been mentioned large amount of energy is released during fusion and fission due to this low binding energy. i can't understand the concept. binding energy is the the...
11. ### Bohr's atom model. some doubts

Homework Statement revered members, one limitation of bohr atom model is that it could not account for distribution and arrangement of electrons. i could not understand this statement, that is, according to bohr , electrons revolve around the nucleus in circular orbits and the necessary...
12. ### Line of action of force?

Homework Statement what is meant by line of action of force? how to understand this concept? suppose i kick a ball and the ball moves in east. then can i say the line of action of force is along the movement of the ball, that is towards the east. i find this concept of line of action of...
13. ### Vidicon television camera

Homework Statement my textbook material on vidicon television camera is inadequate and i would like to know some web links from revered members which could provide some exhaustive coverage of vidicon. could members provide the link? Homework Equations The Attempt at a Solution
14. ### Site that clearly explains transistors

dear mr. mindscrape, thanks a ton for the link.
15. ### Site that clearly explains transistors

both from base to emitter and also from collector to emitter. i am confused which is the starting point and the path. for example, which is positive and which is negative when i find Vbe and Vce.
16. ### Site that clearly explains transistors

Homework Statement friends, i have difficulty in applying KIRCHOFF VOLTAGE LAW in transistors. i am confused because it is totally different from circuits with batteries and resistances where finding the path of closed loop is easy say wheatstone's bridge. but in transistor i cannot...
17. ### Pnp and npn transistor

in pnp circuit, current flows from emitter to base and it reaches the collector. but in npn circuit current flows from base to emitter and to ground. where is the starting point for current in npn circuit. that is the problem for me
18. ### Pnp and npn transistor

Homework Statement revered members, in the following attachment, i could work out the path of current in pnp transistor, that is, from base through RB AND THE output is taken across RL. but i can't figure out the path of current in npn transistor. could u please help? Homework Equations...
19. ### Zener diode as voltage regulator

beautiful explanation sir. i understood fully. thanks for sparing your time in educating novices like me. thanks a lot sir.
20. ### Zener diode as voltage regulator

many thanks mr. mindscrape. you have explained beautifully. but still have one doubt. IN APPLYING KVL, regarding voltage source, when we go from positive to negative, there is fall in potential, so we give -V and when we go from negative to positive, there is a rise in potential so we give + V...
21. ### Zener diode as voltage regulator

Homework Statement revered members, this circuit i have attached is for voltage regulation using zener diode. applying kirchhoffs current law i get current through resistance R is IR=IZ+ IL And the voltage drop across the resistance R is V-VOUT HOW this equation of voltage drop is...
22. ### Voltage regulation using zener diode

Homework Statement when zener diode is used for voltage regulation, voltage source is connected in series to zener diode and load resistance is connected parallel to zener diode. when zener diode is reverse biased, it will enter zener breakdown region. when input voltage increases zener...
23. ### Logic gates using diodes

thanks for the reply. in OR GATE if any input is 1 either of the diodes is forward biased and start to conduct and if both the inputs are 1 then both the diodes start to conduct and the current flows thro the load resistance and we get the output high that is logic 1. but in AND gate, going by...
24. ### Logic gates using diodes

Homework Statement http://www.play-hookey.com/digital/electronics/dl_gates.html [Broken] revered members, in the above link, for OR GATE, when either of the diodes are forward biased we get the output voltage as logic HIGH. but for AND GATE, when when either of the diodes are forward...
25. ### Regarding current sensitivity of galvanometer

Homework Statement a galvanometer with 50 divisions on the scale requires a current sensitivity of 0.1 m A/division. find the galvanometer current? Homework Equations IS= \theta/I TO find the galvanometer current, i multiplied 50 with 0.1 to get the galvanometer current, as instructed...
26. ### Joule's law of heating

Homework Statement in verifying joule's law of heating namely the first law that is law of CURRENT " HEAT IS PROPORTIONAL TO SQUARE OF CURRENT" MY TEXTBOOK MENTIONS THE FOLLOWING LINE the initial temperature of water is measured as THETA1. let W be the heat capacity of the calorimeter and...
27. ### Super conductors

Homework Statement folks, in my textbook it has mentioned 1)superconducting magnetic propulsion system plays a role in launching satellites without the help of rocket 2) superconductors are used to levitate trains above the rails and the example is bullet train i know superconductors are...
28. ### Spectrometer problem

Homework Statement folks, while i do spectrometer experiment to find the angle of the prism and angle of minimum deviation, i encounter the following problems. please let me know how to overcome that 1) i first do the initial adjustment with telescope pointing towards the distant object so...
29. ### Iinterference in thin films due to reflected light

thanks you sir. but on what basis they are equal? adjacent angles? alternate angles? or something else.
30. ### Iinterference in thin films due to reflected light

sir, i understood the concept. but, in my attachment SA is incident ray and NA is the normal, so <SAN is angle of incidence. but, NC is normal to AT and CQ. <i is between AC and CN. how can it be termed as angle of incidence. because both AT and CQ, according to my attachment are reflected rays...
31. ### Iinterference in thin films due to reflected light

Homework Statement dear revered members, please find the attached image for the topic interference in thin films due to relection. Homework Equations my questions are 1) angle between the incident ray or reflected ray or refracted ray is called angle of incidence, angle of reflection...
32. ### Electrostatics problem

Thanks sir. i understood now
33. ### Electrostatics problem

sir, it has already been mentioned about the charge possessed by each individual ball. When they come in contact some redistribution of charge occurs. if they are separated won't they get their initial charges?
34. ### Electrostatics problem

Homework Statement three small identical balls have charges -3C,8C and 4C respectively. they are brought in contact and separated. calculate charge on each ball? Homework Equations q=(q1+q2+q3)/3 The Attempt at a Solution what is the need for dividing by 3. why not simply add the...
35. ### Field due to two parallel sheets of charge

Thanks a lot sir. I understood now
36. ### Gaussian surface

Thanks a lot mr.kuruman and mr. cyosis. now i understood the concept. thanks for sparing your valuable time.
37. ### Field due to two parallel sheets of charge

sir, the sheet on the left side has positive charge so field points away but the sheet on the right has negative charge, then how E1- points away? it should point inwards, shouldn't it? apologize me if my query is silly. just i want to know the concept, sir.
38. ### Field due to two parallel sheets of charge

Homework Statement friends, in the given attachment, how the directions of E1 and E2 are drawn? i mean what is the procedure to draw the directions. help will be greatly appreciated. thanks in advance Homework Equations The Attempt at a Solution
39. ### Gaussian surface

but sir, if i draw a cylinder the plance face is elliptical in shape. dA should be perpendicular to the surface. i can draw dA in top direction, right direction and left direction. all these directions are perpendicular to the surface. what is the correct choice of direction.
40. ### Gaussian surface

Homework Statement In the case of calculating electric field due to an infinitely long line charge, we assume cylinder to be a gaussian surface and electric field and small area element of the cylinder acts along the same direction at the curved surface and they act perpendicular direction at...