Q1: |
The compact disc play head UV bulb if you put two together directly oppsitethe sensors will it burn a paperon sunlight rays like convergeing lens with out electricity? |
Uziel B'nai Noach O'shobek |
14/4/2010 |
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Q2: |
How do we protect moving parts from rusting? |
ZOYA |
23/10/2009 |
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Q3: |
effect of temperature on conductivity of materials |
hyde wiiliam |
26/2/2008 |
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Electrical conductivity is strongly dependent on temperature. In metals, electrical conductivity decreases with increasing temperature, whereas in semiconductors, electrical conductivity increases with increasing temperature. Current is the sum effect of electrons moving through the copper wire. When the wire heats up, for example, by a torch, it causes the electrons to collide around more than before. Therefore, flow is with less ease. This means that the copper wire now has a higher resistance. The general rule is "the higher in temperature the wire is, the higher the resistance to electrical flow. |
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Q4: |
Thank you for replying to our questions. |
abc |
10/2/2008 |
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You are welcome |
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Q5: |
I had asked a question earlier regarding the properties of an electron moving in a magnetic field.You have said that the direction changes. Can you please explain how. |
lyra |
10/2/2008 |
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It moves along a curved path in a magnetic field hence its direction changes continuously |
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Q6: |
Why is rubber a bad conductor of heat? Is it that the molecular structure is more dense? |
dreebabe |
9/2/2008 |
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No it is not due to density of molecules but the fact that it consists of long chains of monomers of isoprene molecules linked into loosely twisted chains. These chains do not have any free electrons. This makes rubber an insulator i.e. it does not conduct electricity. |
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Q7: |
Why have you stopped replying to our questions? |
abc |
8/2/2008 |
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We request you to wait for some days, sometimes the overload of questions becomes too much for our research team to answer and their is a delay in answering them. We will definitely reply within a few days time. |
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Q8: |
Which of the following properties of a proton can change while it moves freely in a magnetic field? (a)mass,(b)speed,(c)velocity,(d)momentum Give reason. |
lyra |
5/2/2008 |
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Even though for all-purpose a proton is made up of three quarks that can behave independently when subjected to force but for present we will consider them as one. The mass of the proton will not change due to the field as the effect of field has no bearing on mass, neither the speed will change but the velocity will change as the direction is changing and also momentum will change as it is related to velocity vector. |
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Q9: |
What is the difference between short circuiting and overloading? |
shreya |
5/2/2008 |
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A short circuit is an accidental low-resistance connection between two nodes of an electrical circuit that are meant to be at different voltages. In overloaded wires, larger than intended electrical current flows through a conductor, leading to excessive generation of heat. It can also overheat, sometimes causing damage to the wire's insulation thus creating a condition for short circuit |
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Q10: |
What happens if only a voltmeter is connected to a battery? |
pearl |
25/1/2008 |
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It will measure the voltage across the terminals |
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Q11: |
which is the most bad conductor of heat ,glass water or rubber |
shaukat |
26/5/2007 |
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Thermal conductivity in W/m K at given temperature of 293 K is highest for pyre glass is 1, next is liquid water at 0.598, wood is 0.14 (included from our side), sponge rubber is 0.05, so rubber is worst conductor. However Plastics are the worst with celluloid at 0.02, polystyrene foam at 0.033, mylar foil at 0.0001. Wool also has 0.04 index, making it better than rubber. |
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Q12: |
is wax a good conductor of heat? |
sardine |
1/3/2006 |
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Wax is a poor conductor of heat, Thermal conductivity @ 20°C, w/m °C lies between 0.170-0.190 |
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