Can you find the mistake

Answer:Actually the mistake is not in the numbers.The mistake is in the 1st line.

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What is geostationary satellite?

What is geostationary satellite?

 

A geostationary satellite is an earth-orbiting satellite, placed at an altitude of approximately 35,800 kilometers (22,300 miles) directly over the equator, that revolves in the same direction the earth rotates (west to east). At this altitude, one orbit takes 24 hours, the same length of time as the earth requires to rotate once on its axis. The term geostationary comes from the fact that such a satellite appears nearly stationary in the sky as seen by a ground-based observer. BGAN, the new global mobile communications network, uses geostationary satellites.

A single geostationary satellite is on a line of sight with about 40 percent of the earth's surface. Three such satellites, each separated by 120 degrees of longitude, can provide coverage of the entire planet, with the exception of small circular regions centered at the north and south geographic poles. A geostationary satellite can be accessed using a directional antenna, usually a small dish, aimed at the spot in the sky where the satellite appears to hover. The principal advantage of this type of satellite is the fact that an earthbound directional antenna can be aimed and then left in position without further adjustment. Another advantage is the fact that because highly directional antennas can be used, interference from surface-based sources, and from other satellites, is minimized.

Geostationary satellites have two major limitations. First, because the orbital zone is an extremely narrow ring in the plane of the equator, the number of satellites that can be maintained in geostationary orbits without mutual conflict (or even collision) is limited. Second, the distance that an electromagnetic (EM) signal must travel to and from a geostationary satellite is a minimum of 71,600 kilometers or 44,600 miles. Thus, a latency of at least 240 milliseconds is introduced when an EM signal, traveling at 300,000 kilometers per second (186,000 miles per second), makes a round trip from the surface to the satellite and back.

There are two other, less serious, problems with geostationary satellites. First, the exact position of a geostationary satellite, relative to the surface, varies slightly over the course of each 24-hour period because of gravitational interaction among the satellite, the earth, the sun, the moon, and the non-terrestrial planets. As observed from the surface, the satellite wanders within a rectangular region in the sky called the box. The box is small, but it limits the sharpness of the directional pattern, and therefore the power gain, that earth-based antennas can be designed to have. Second, there is a dramatic increase in background EM noise when the satellite comes near the sun as observed from a receiving station on the surface, because the sun is a powerful source of EM energy. This effect, known as solar fade, is a problem only within a few days of the equinoxes in late March and late September. Even then, episodes last for only a few minutes and take place only once a day.

In recent years, low earth orbit (LEO) satellite systems have become popular. This type of system employs a fleet or swarm of satellites, each in a polar orbit at an altitude of a few hundred kilometers. Each revolution takes between 90 minutes and a few hours. Over the course of a day, such a satellite comes within range of every point on the earth's surface for a certain period of time. The satellites in a LEO swarm are strategically spaced so that, from any point on the surface, at least one satellite is always on a line of sight. The satellites thus act as moving repeaters in a global cellular network. A LEO satellite system allows the use of simple, non-directional antennas, offers reduced latency, and does not suffer from solar fade. These facts are touted as advantages of LEO systems over geostationary satellites.

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Does a fully charged battery weight more than when it's empty?

Does a fully charged battery weight more than when it's empty?

Yes because of E= mc*2
When you test the electrolite in a lead acid battery,as the battery charges the sulphuric acid becomes denser which gives it more mass so it "weighs" more.

Try it at home weigh a flat car battery on some reasonably accurate scales then charge it up and weigh it again.All you have added is potential energy.

The speed of light is constant,the energy has increased(it will start your car) so the only thing that can change is the mass.

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In the earth where the gravity of the earth becomes zero..?

In the earth where the gravity of the earth becomes zero..?

In a perfectly-shaped sphere, with a smooth surface, and composed of exactly the same substance with the same density throughout it, the force of gravity is zero at the exact center of the sphere. That does NOT mean that 'gravity becomes zero' at the center. It means that at the center, for every speck of mass pulling on you in any direction with any force, there's another speck of mass pulling you in exactly the opposite direction with exactly the same amount of force, so the whole thing adds up to zero. In the real Earth, we can't tell exactly where that point is, because the Earth is not a perfect sphere shape, It doesn't have a smooth surface, and we don't know every last little detail about the distribution of mass inside it.

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Which Came First, The Chicken Or The Egg?

Chickens, as a species, became chickens through a long, slow process of evolution. At some point, a chicken-like bird produced an offspring that, due to some mutation in its DNA, crossed the threshold from mere chicken likeness into chicken actuality. That is to say, a proto-chicken gave birth to a real-life official chicken. And since that real-life official chicken came out of its own egg, we can say that the egg came first.

Another way to look at the question would be to ask which came first in evolutionary history. Once again, the egg takes precedence. Many characteristics of the modern avian egg—namely an oblong, asymmetrical shape and a hardened shell—were in place before birds diverged from dinosaurs about 150 million years ago. "A lot of the traits that we see in bird eggs evolved prior to birds in theropod dinosaurs," says Darla Zelenitsky, of the University of Calgary.

Another key moment in the history of avian eggs occurred at least 150 million years before that, when a subset of four-limbed vertebrates evolved to produce amniotic eggs. The embryos within the eggs were surrounded by three fluid-filled membranes that provide nourishment, protection, and a way to breathe. The earliest amniotic eggs contained large amounts of yolk, says James R. Stewart, a reproductive physiologist at East Tennessee State University. "You still see that in birds, crocodilians, and snakes," he explains. Like other placental mammals, we humans lost our yolk somewhere along the line, but our eggs still come with a vestigial yolk sac.

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Why 0! is equal to 1 ..??

Why 0! is equal to 1 ..??

We Know ,

n! = n x (n-1)!

Dividing both sides by n , We get

n!/n = n x (n-1)!/n 

Or, n!/n = (n-1)!

Or, (n-1)! = n!/n

Now , Putting n=1 , We get

(1-1)! = 1!/1

i.e. 0! = 1 

  

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Are there any ways to pass through a laser sensor without being detected?

Are there any ways to pass through a laser sensor without being detected?

 

 As the question asked about "passing through" a laser sensor, the answer speaks to the breaking of the laser beam. And that's not something that you can do. Breaking the beam will trigger the sensor. If an investigator has an idea about the laser itself, it may be possible to "substitute" for the beam being used in the sensor, but most laser sensors will pick up any attempts to dump another beam in over the top of the extant one. Forget about mirrors and such. The "smart" laser sensors use a beam too small to "split" with mirrors. Rerouting with fiber optics is equally futile. What you've seen on those TV shows and in movies is pie in the sky - you can't do that. About all you can do is detect the beam and avoid it.

It might be worth noting that anyone using a laser may also be using infrared IR sensors. (I would.) These sensors are not lasers and are completely passive; they emit nothing at all and cannot be "seen" in any way. (See the link below "What is a PIR alarm system?" for more details). If something is worth protecting with a laser, an IR detector would be an easy "add on" to that system. In fact, given a choice, the IR would be a better first choice.

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Electric Field vs. Magnetic Field

Electric Field vs. Magnetic Field

The area around a magnet within which magnetic force is exerted, is called a magnetic field. It is produced by moving electric charges. The presence and strength of a magnetic field is denoted by “magnetic flux lines”. The direction of the magnetic field is also indicated by these lines. The closer the lines, the stronger the magnetic field and vice versa. When iron particles are placed over a magnet, the flux lines can be clearly seen. Magnetic fields also generate power in particles which come in contact with it. Electric fields are generated around particles that bear electric charge. Positive charges are drawn towards it, while negative charges are repelled.

A moving charge always has both a magnetic and an electric field, and that’s precisely the reason why they are associated with each other. They are two different fields with nearly the same characteristics. Therefore, they are inter-related in a field called the electromagnetic field. In this field, the electric field and the magnetic field move at right angles to each other. However, they are not dependant on each other. They may also exist independently. Without the electric field, the magnetic field exists in permanent magnets and electric fields exist in the form of static electricity, in absence of the magnetic field.

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Does a vacuum cleaner work in space?

Does a vacuum cleaner work in space?

 

No. First of all it wouldn't stay on the ground. and why would you need to vacuum?
A vacuum cleaner depends on a difference in air pressure to operate. With no air pressure in space, there could be no difference in air pressure and thus no operation.

Inside a manned spacecraft, which is usually pressurized a vacuum cleaner will obviously work just fine; especially for collecting and disposing of water globules. Also the standard NASA space toilet uses a modification of a vacuum cleaner for urine collection. 

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Would a magnet work in a vacuum or space?

Would a magnet work in a vacuum or space?

 

Magnets work because their atoms are aligned in certain orientation so that the magnetic field is not chaos but is organized as ripples around the matter. Such organized electromagnetic field of any nature can exist without any supporting media like air or water. If you think space is vacuum then you are wrong again. There is a lot of black or dark matter (invisible to current scientific equipment) in this universe and lots of particles like cosmic rays emitted by stars and galaxies. So magnets will work regardless of vacuum or space.  

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Would a magnetic compass be suitable to be used for space travel..?

Would a magnetic compass be suitable to be used for space travel..?

 

No. Magnetic compasses work based on the Earth's mantic field, in space there is no magnetic field for the compasses to work with. A different system, possibly similar to Global Positioning System (GPS) might work, call it the Universal Positioning System. On certain rocky planets it could work, but some planets don't have a magnetic field, like Mars. So a traditional magnetic compass wouldn't work in space, or at least it won't get you where you want to go.

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How compass apps can tell direction..??

 How compass apps can tell direction..??

If you were to go back in history and meet with the explorers and navigators of yesteryear, they would probably be wielding — at least one — magnetic compass. Whip out your compass app on your smartphone, and they’d probably be flabbergasted — well, with that and your time machine. But how has the compass worked to help everyone from ancient Chinese seafarers to today’s Boy Scouts of America? And how exactly does that timeworn technology work in your iPhone?

First, we’ll go over the magnetic compass. This trustworthy piece of equipment has been around since 200 BCE, according to William Lowrie, a professor emeritus at ETH Zurich. Navigators started using this compass regularly on land and sea closer to 1000 CE, in present-day China. The standard magnetic compass of the 20th century is made up of a magnetized needle in its heart with a face showing cardinal directions — north, south, east, and west. The needle is mounted on a surface with low friction so that it can easily turn; if held flat, one end of the needle will point toward magnetic north and one to magnetic south.

The compass is able to determine north and south due to the magnet’s interaction with the Earth’s magnetic field. The cause of the magnetic field is not completely known, but geologists have made hypotheses regarding the phenomenon by analyzing the layers of the Earth. The Earth is made up of an outer crust, followed by the upper mantle, the inner mantle, the outer core, and then finally the inner core at the very center. The inner core is made up mostly of molten iron, but the very center of the inner core is under so much pressure that the iron becomes solid, according to howstuffworks.com. It is believed that the rotation of the Earth and the immense heat from the core cause the iron to move in a rotational pattern. This rotational pattern may be the source of the magnetic field that we see on Earth. The field produced is very weak, however, which is why the needle on the compass needs to be very lightweight and on a surface with minimal friction.

As expected with any technology created over two millenniums ago, the compass has its issues. First, it has to be completely level to work — making it rather difficult to use on something like an airplane. Also, a magnetic compass can take a long time to correct itself. Another confusing thing is that the magnetic north pole is actually the geographical south pole (and vice-versa).

So if the traditional needle compass works because of a small magnet, how do the compass apps in phones work? As it turns out, the smartphones do have a small magnetometer, which can measure the Earth’s magnetic field. This information is combined with an accelerator inside the phone. The accelerator gets information regarding the phone’s position in space. It is able to pinpoint the phone’s position from solid-state sensors within the phone that can measure their tilt and movement. The information provided by these devices means that the compass app can display cardinal directions no matter which orientation the phone is in, according to the algorithmic software development company Sensor Platforms.

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Does light have mass?

Does light have mass?

 

The short answer is "no", but it is a qualified "no" because there are odd ways of interpreting the question which could justify the answer "yes".

Light is composed of photons, so we could ask if the photon has mass.  The answer is then definitely "no": the photon is a massless particle.  According to theory it has energy and momentum but no mass, and this is confirmed by experiment to within strict limits.  Even before it was known that light is composed of photons, it was known that light carries momentum and will exert pressure on a surface.  This is not evidence that it has mass since momentum can exist without mass.

Sometimes people like to say that the photon does have mass because a photon has energy E = hf where h is Planck's constant and f is the frequency of the photon.  Energy, they say, is equivalent to mass according to Einstein's famous formula E = mc².  They also say that a photon has momentum, and momentum p is related to mass m by p = mv.  What they are talking about is "relativistic mass", an old concept that can cause confusion. Relativistic mass is a measure of the energy E of a particle, which changes with velocity.  By convention, relativistic mass is not usually called the mass of a particle in contemporary physics so, at least semantically, it is wrong to say the photon has mass in this way.  But you can say that the photon has relativistic mass if you really want to.  In modern terminology the mass of an object is its invariant mass, which is zero for a photon.

If we now return to the question "Does light have mass?", this can be taken to mean different things if the light is moving freely or trapped in a container.  The definition of the invariant mass of an object is m = sqrt{E²/c⁴ - p²/c²}.  By this definition a beam of light is massless like the photons it is composed of.  However, if light is trapped in a box with perfect mirrors so the photons are continually reflected back and forth in both directions symmetrically in the box, then the total momentum is zero in the box's frame of reference but the energy is not.  Therefore the light adds a small contribution to the mass of the box.  This could be measured--in principle at least--either by the greater force required to accelerate the box, or by an increase in its gravitational pull.  You might say that the light in the box has mass, but it would be more correct to say that the light contributes to the total mass of the box of light.  You should not use this to justify the statement that light has mass in general.

Part of this discussion is only concerned with semantics.  It might be thought that it would be better to regard the mass of the photons to be their (nonzero) relativistic mass, as opposed to their (zero) invariant mass.  We could then consistently talk about the light having mass independently of whether or not it is contained.  If relativistic mass is used for all objects, then mass is conserved and the mass of an object is the sum of the masses of its parts.  However, modern usage defines mass as the invariant mass of an object mainly because the invariant mass is more useful when doing any kind of calculation.  In this case mass is not conserved and the mass of an object is not the sum of the masses of its parts.  Thus, the mass of a box of light is more than the mass of the box and the sum of the masses of the photons (the latter being zero).  Relativistic mass is equivalent to energy, which is why relativistic mass is not a commonly used term nowadays.  In the modern view "mass" is not equivalent to energy; mass is just that part of the energy of a body which is not kinetic energy.  Mass is independent of velocity whereas energy is not.

Let's try to phrase this another way.  What is the meaning of the equation E=mc²?  You can interpret it to mean that energy is the same thing as mass except for a conversion factor equal to the square of the speed of light.  Then wherever there is mass there is energy and wherever there is energy there is mass.  In that case photons have mass, but we call it relativistic mass.  Another way to use Einstein's equation would be to keep mass and energy as separate and use it as an equation which applies when mass is converted to energy or energy is converted to mass--usually in nuclear reactions.  The mass is then independent of velocity and is closer to the old Newtonian concept.  In that case, only the total of energy and mass would be conserved, but it seems better to try to keep the conservation of energy.  The interpretation most widely used is a compromise in which mass is invariant and always has energy so that total energy is conserved but kinetic energy and radiation does not have mass.  The distinction is purely a matter of semantic convention.

Sometimes people ask "If light has no mass how can it be deflected by the gravity of a star?".  One answer is that all particles, including photons, move along geodesics in general relativity and the path they follow is independent of their mass.  The deflection of starlight by the sun was first measured by Arthur Eddington in 1919.  The result was consistent with the predictions of general relativity and inconsistent with the newtonian theory.  Another answer is that the light has energy and momentum which couples to gravity.  The energy-momentum 4-vector of a particle, rather than its mass, is the gravitational analogue of electric charge.  (The corresponding analogue of electric current is the energy-momentum stress tensor which appears in the gravitational field equations of general relativity.)  A massless particle can have energy E and momentum p because mass is related to these by the equation m² = E²/c⁴ - p²/c², which is zero for a photon because E = pc for massless radiation.  The energy and momentum of light also generates curvature of spacetime, so general relativity predicts that light will attract objects gravitationally.  This effect is far too weak to have yet been measured.  The gravitational effect of photons does not have any cosmological effects either (except perhaps in the first instant after the Big Bang).  And there seem to be far too few with too little energy to make any noticeable contribution to dark matter.

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