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10 electric dipoles, each of dipole moment 10Cm, are located symmetrically inside a closed Gaussian surface. Calculate the electric flux of the surface.

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A student measures the time period of 100 oscillations of a simple pendulum four times. The data set is 90s,91s,92s & 95s. If the mimimum division in the measuring clock is 1s, then find the reported mean time ?

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Let’s first find the mean value of time:
{tex}t_{mean}={t_1+t_2+t_3+t_4\over 4}{/tex}
= {tex}{90+91+95+92\over 4}= 92 {/tex}
Then, we can find the absolute error for each measurement:
{tex}\Delta t_1=t_{mean}t_1= 9290=2{/tex}
{tex}\Delta t_2=t_{mean}t_2= 9291=1{/tex}
{tex}\Delta t_3=t_{mean}t_3= 9292=0{/tex}
{tex}\Delta t_4=t_{mean}t_4= 9295=3{/tex}
Let’s calculate the mean absolute error:
{tex}\Delta t_{mean}={ \Delta t_1+ \Delta t_2+ \Delta t_3+ \Delta t_4\over 4}{/tex}
= {tex}{2+1+0+3\over 4}= 1.5{/tex}{tex}\approx 2{/tex}
Therefore, the reported mean time should be 92 ± 2s
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Two metallic balls are charged and suspended by threads from the same point. The whole set up is taken to space where ther is no gravity. What is the angle between the threads and the tension in the string?
Plsss reply asap........

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An electric charge A of strength 'q' exerts a force'F' on another similar charge B of strength 'q' separated by a distance 'r' in air.
(a) If a third charge C of strength '2q' is placed midway between the charges A and B, what is the force exerted by A on B?
(b) If the magnitude of each charge A and B is doubled and the charges are placed in a medium of relative permitivity 16, at a distance 1/2r, determine the force exerted by A on B?
Plzz reply asap......

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What are the dimensions of permitivity of a medium?

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Dimensions of {tex}\in{/tex} electrical permittivity of medium is {tex}[M^{1}L^{3}T^4A^2].{/tex}
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a 100w buld and 500w bulb are joined in parellel to mains which will draw more current.

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500w bulb will draw more current.
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Is the glass is amorphous?

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The molecules then have a disordered arrangement, but sufficient cohesion to maintain some rigidity. In this state it is often called an amorphous solid or glass.
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Is the concept of electric flux varies for a plane object and ring?
How?

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Is the concept of electric flux varies for a plane object and a ring ?
How?

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Derive an expression for the electric field E due to a system of chages q_{1 }and q_{2} with position vector r_{1 }and r_{2 }at a distance r with respect to common origin.

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a current i flows through a uniform wire of diameter d when the mean electron drift velocity is v .the same current flows through a wire of length d/2 made of same material if the mean drift velocity is________

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Prove Gauss theorm for closed surface of asymmetrical shape?

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How along non zero component unit test charge move

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What is capacitance of a conductor?

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The measure of the ability of a conductor to store electric charge or energy is known as capacitance of a conductor.
OR
Capacitance of a conductor is the amount of charge that a capacitor can store per unit of potential difference.
C = q/V
Where, C stands for Capacitance
q stands for charge on a conductor
V stands for potential of the conductor
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Why two equipotential surface are not interested?

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because two different equipotential surface have different electric potential, so if they intersect then the point of intersection will have two different potentials at the same point which is not possible.
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'automobiles ignition failure occurs in damp weather.' explain, why??

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The insulating porcelain of the spark plugs accumulates a film of dirt. The surface dirt is hygroscopic and picks up moisture from the air. Therefore, in humid weather, the insulating porcelain of the plugs becomes quasiconductor. This allows an appreciable proportion of the Spark to leak across the surface of the plug instead of discharging across the gap.
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In filling the gasoline tank of an aeroplane, the metal nozzle of the hose from the gasoline truck is always carefully connected to the metal of the aeroplane by a wire, before the nozzle is inserted in the tank. explain why??

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The aeroplane and the gasoline truck usually have wheels with rubber tyres, they are insulated from the ground. Further, the service ramps are usually made of concrete and are not necessarily good conductors to the earth. Therefore, inspite of grounding metallic ropes, the aeroplane and the truck could remain charged.A spark may jump and ignite the explosive gasoline, when the metal nozzle is brought near the aeroplane. The connection of metal of the aeroplane and the nozzle of the hose with a wire avoids any unbalance of charge and hence the risk of gasoline.
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A pendulum bob of mass 80mg carrying a charge of 2 * 10^{8 C} is at rest in a horizontal uniform electric field of 2*10^{4 }Vm^{1}.Find the tension in the thread of the pendulum and the angle it makes with the vertical.

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Given: mass = 80 mg = 80 × 10^{6} Kg
Charge q = 2 × 10^{8} C
E = 2 × 10^{4} Vm^{1}
Let T is tension in string and {tex}\theta{/tex}
is angle of string with vertical.
In equilibrium
{tex}Tsin\theta = qE \ ....(1){/tex}
{tex}Tcos\theta = mg \ ....(2){/tex}
Divide (1) by (2), we get
{tex}tan\theta = {qE\over mg}{/tex}
=> {tex}tan \theta = {2\times 10^{8}\times 2\times 10^4\over 80\times 10^{6}\times 10}{/tex}
=> {tex}tan \theta = 0.5{/tex}
=> {tex}\theta = 27^°{/tex}
Now Tension T = {tex}qE\over sin \theta{/tex}= {tex}{2\times 10^{8}\times 2\times 10^4\over sin 27^°}{/tex}
= 8.8 × 10^{4} N
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what is drift velocity

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The drift velocity is the average velocity that a particle, such as an electron, attains in a material due to an electric field. It can also be referred to as axial drift velocity.
In general, an electron will propagate randomly in a conductor at the Fermi velocity
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Name the dielectric whose molecules have zero and non zero dipole moment.

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(i) The dielectric having non zero dipole moment is water.
(ii) The dipole having zero dipole moment is diamond (or silicon).
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Two charges of 2microC but opposite in sign are placed 1pcm apart.Calculate the electric field at a point distance 10cm from the midpoint on the axial line of dipole.

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Ans. Given :
Charge q = 2 mC = {tex}2 \times 10 ^{6} C{/tex}
Distance b/w them (2a) = 10 cm = 10^{1} m
Distance from midpoint on axial line r = 10 cm = 10^{1 } m
We Know
p = {tex}q \times 2a{/tex} = {tex}2 \times 10 ^{6} \times 10^{1} = 2 \times 10 ^{7} {/tex}
Electric field due tp dipole on Axial line E = {tex}{1\over 4\pi \in } \times {2p\over r^2}{/tex}
= {tex}9\times 10 ^ 9 \times 2 \times 2 \times 10^{7}\over 10^{2} {/tex} = {tex}36 \times 10 ^ 7 \ N/C{/tex}
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Using Gauss Law, show that electric field inside a conductor is zero.

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Is there some method of charging a conductor without rubbing it with another object and without bringing it into contact with a charged body?

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Yes method of induction.
Just bring the charged body closer to another uncharged body,
Induction charging is a method used to charge an object without actually touching the object to any other charged object.
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Equal charges each of 20 meucoulumb are placed at x=0,2,4,8,16cm on X axis . find the force experienced by the charge at x=2cm?

but the ans given in the book is 1.2 X 10^{3 }N
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Solution:
Let q_{1},q_{2 },q_{3 },q_{4 }and q_{5 } be the charges at x = 0,2,4,8,16 on xaxis.
Let F be the resultant force.
F_{1}  Force on q_{2} due to q_{1}
F_{3}  Force on q_{2} due to q_{3}
F_{4}  Force on q_{2} due to q_{4}
F_{5}  Force on q_{2} due to q_{5}
F = F_{1}+F_{3}+ F_{4}+ F_{5}
F = {tex}k {q_1q_2\over (r_{21})^2} + k {q_3q_2\over (r_{23})^2}+ k {q_1q_4\over (r_{24})^2}+ k {q_1q_5\over (r_{25})^2}{/tex}
{tex}F = k {qq\over (r_{21})^2} + k {qq\over (r_{23})^2}+ k {qq\over (r_{24})^2}+ k {qq\over (r_{25})^2}{/tex}
[q_{1=}q_{2 =}q_{3 =}q_{4 = }q_{5 } = q = {tex}20\times 10^{6} C{/tex}]
{tex}F = k {q^2\over (r_{21})^2} + k {q^2\over (r_{23})^2}+ k {q^2\over (r_{24})^2}+ k {q^2\over (r_{25})^2}{/tex}
{tex}F = k q^2\left[{1\over (r_{21})^2} + {1\over (r_{23})^2}+ {1\over (r_{24})^2}+ {1\over (r_{25})^2}\right]{/tex}
{tex}r_{21} = 2cm = 2\times 10 ^{3}m\\ r_{23} = 2cm = 2\times 10 ^{3}m \\ r_{24} = 6cm = 6\times 10 ^{3}m\\ r_{25} = 14cm = 14\times 10 ^{3}m{/tex}
Putting values of all, we get
{tex}F = 9\times10^9 \times 20\times 10^{6}\left[{1\over (2\times 10^{2})^2} + {1\over (2\times 10^{2})^2}+ {1\over (6\times 10^{2})^2}+ {1\over (14\times 10^{2})^2}\right]{/tex}
F = {tex}1.92\times 10^4 N{/tex}
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Two charges +q and q are kept at (x2,0) and (x6,0) respectively in the xy plane. Fond magnitude and direction of net electric field at organ (0,0)

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The RMS value of the electric field of the light comimg from the sun is 720N/C. The average total energy density of electomagnetic wave is

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What are the combinations of NOR & NAND gate

no , I am asking their combinations like
2 NAND gate makes
3 NAND gate makes which gate
same as NOR
2NOR , 3 NOR

what their combinations are called
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They themselves are the combinations
NOR GATEOR GATE + NOT GATE
NAND GATE AND GATE + NOT GATE
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What is POYNTING VECTOR ? &
What does it represent ?

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In physics, the Poynting vector represents the directional energy flux density (the rate of energy transfer per unit area) of an electromagnetic field. The SI unit of the Poynting vector is the watt per square metre (W/m^{2}).
The Poynting vector is defined as
<dl> <dd></dd> </dl>where
 E is the electric field vector;
 H is the magnetic field's auxiliary field vector.
 S is Poynting vector
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When a wire of resistance R is streched and its radius becomes r/2 , then new resistance is ?

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Ans. Let the Initial Length of Wire = l
Final length of Wire = L
Intial Radius of wire = r
FInal Radius of Wire r_{1} = {tex}r\over 2{/tex}
So, Initial Volume of Wire = Final Volume of Wire
{tex}=> \pi r^2 l = \pi r_1^2L{/tex}
{tex}=> r^2 l = ({r\over 2})^2L{/tex}
{tex}=> r^2 l = {r^2\over 4}L{/tex}
{tex}=> L = 4l{/tex}
Initial Area of Cross Section of wire (A) = {tex}\pi r^2{/tex}
Final area of Cross section of wire (A') = {tex}\pi r_1^2 = \pi{r^2\over 4}{/tex}
Initial Resistance of Wire (R)= {tex}\rho {l\over A} = \rho {l\over \pi r^2}{/tex}
Final Resistance of Wire (R') = {tex}\rho {L\over A'} = \rho {4l\over {\pi r^2\over 4}} ={ \rho 4\times 4l\over\pi r^2}{/tex}
= {tex}16\rho{l\over \pi r^2} = 16R{/tex}
So new Resistance ll be 16 times of initial Resistance.
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