Q. & A.s SCIENCE & TECH. – 8

Q. &  A.s  ‑‑‑  SCIENCE  & TECH. – 8

221Q. What do you mean by electricity?

Electricity is the flow of electrons through a conductor.

222Q. Why fuse is blown out if phase and neutral are joined?

If phase and neutral are joined the resistance becomes zero.

V=ir ohm’s law

I = v/r

If r= 0

I becomes infinity. That is why the fuse is blown off.

223Q. When you switch on fan, why doesn’t it rotate in another direction?

It is Maxwell’s rule. If thumb indicates the direction of the direction of the current, folded fingers indicate the direction of the magnetic field in which the fan rotates.

224Q. Why can’t we send current in dc form?

DC travels through the entire conductor. That is why it is very slow. Secondly there will be more losses.

225Q. Why a/c is called skin current?

A/C travels only on the surface of the conductor. That is why it is called skin current.

226Q. Why there are more strands in an a/c wire?

A/C travels only on the surface of the conductor. That is why it is called skin current. If there are more number of strands more conduction. That is why there are more stands in a/c wire.

227Q. Why there is only one wire in dc wire?

In DC electrons flow through the entire conductor. That is why if the diameter is more, more conduction takes place.

228Q. What is the velocity of electricity?

Electricity is the flow of electrons in a conductor. The velocity of electrons in  a conductor is equal to the velocity of light.

229Q. Why doen’t the lotus leaf get wer?

Cuticle, is a layer of was-like substance which is simple lipid. It contains one molecule of fatty acid esterified with one molecule of long chain of alcohols instead of glycerol. water does not stay on the leaf because of the wax like substance.

230Q. What is the difference between TV screen and computer monitor?

A         The computers are capable of accepting signals only from the central processing unit of computer but Tv receives signals from a broadcasting station.

2.         how many dots [pixel] are to be transmitted per second to form an image is generally 15 MHz in a computer but for TV it is only 6 MHz.

3.         The horizontal scanning frequency of these monitors varies from 15 KHz to 155 KHz but in TV its fixed range is 15.6 or 15.7 KHz.

4.         The pixel power is to be more because the operator sits within two feet from the monitor.

231Q. What is the temperature of the ice cream?

-          30^oc

-           

232Q. Why there is a meshed-wires system under heavy conducting wires?

The heavy transmission line can induce em energy. If there is no protection it can be induced into other things which can damage or create havoc. That is why there is a wired mesh under heavy lines.

233Q. Why can’t we make pakodi in boiling water?

Pakodi dough contains water which can evaporate at 100^oC. Water too boils at the same. Same temperature cannot remove water. Instead the dough becomes cream like. If it is edible oil generally it will higher than 200^oC. This can remove water from the dough and make pakodi eatable.

234Q. What is bullet proof fabric?

The textile contains 16 to 24 layers of nylon cloth of heavy weave. When these layers are woven or stitched together they can stop the bullet.

235Q. What is bullet proof glass?

High strength ceramics such as silicon nitride, dual hardness steel and layers of heavy nylon fabric make a bullet proof glass impervious to bullets. The hard ceramic stops the bullet abruptly, dissipates it energy as it destroys the first layers of the glass at the point of impact and entangles it in a coarse mesh.

236Q. Heavy sounds shatter glass. Why?

Aircraft sound, bomb sound etc. have different types of sounds. If the sound created has the frequency of the glass resonance is created. The frame of the glass window does not allow glass to resonate. That is why it breaks.

237Q. What is magnetor?

Magnetors are magnetic stars.

The amount of magnetic radiation liberated by the sun is liberated by a magnetor in one second.

The first magnetor is SGR 1806-20.

It is 40,000 L.Y.s from the earth.

Neutron stars are powerful than the ordinary stars.

Magnetors are 100 times more powerful than neutron stars.

Its magnetic power is 10¹⁵X g.

Its outer temperature is 10⁷ degrees C.

238Q. How can a pig save man?

The scientists of North Carolina, Duke University, have found out that pig’s heart, liver and kidneys can replace human parts.  The patients who were going to die were saved.

239Q. Who is computer Adam?

Joseph Paul Jernigton, Texas,  was a 39 years old murderer. As per his wish, after killing him, his body was cut into 1800 slices, and those slices were scanned from all the angles in Computed Tomography [CT], magnetic resonance imaging [MRI]. That digitalized information is converted into software. He is called computer Adam?

240Q. Who is Computer Eve?

A 59 years old housemaker died. As per her wish, her body was cut into 5000 slices, and those slices were scanned from all the angles in Computed Tomography [CT], magnetic resonance imaging [MRI]. That digitalized information is converted into software. She is called computer Eve?

241Q. What is space mirror?

A carrying this mirror went into geostationary orbit and opened. The sun’s light reflected by this mirror illuminated Siberia. It was launched by USSR. Because in this area nights are very long. It is also called artificial moon.

242Q. Bacteria is diminishing the power of chemicals. Why?

Soaps, lotions, and other chemicals are used in our houses to clean something. These chemicals contain a chemical – trycloson -that can prevent bacteria growth. But these chemicals are changing the genetic structure of bacteria.

243Q. Who are aghoras?

They live in Kasi. They eat dead human dead bodies. They get these dead bodies from the Ganga. People leave their dead people as they are so that they can get moksham. Some times they even eat dead dogs, pigs, crows, etc.

244Q. What planet has the lowest escape velocity?

Escape velocity depends on mass. The planet with the lowest mass is Mercury.

245Q. Does every planet have an escape velocity?

"Escape velocity" is defined as the velocity required in order to guarantee that the object will not fall back under the influence of the planet's gravitational attraction. If it's possible to escape...  the escape of velocity of each planet is different.

This relates to the speed, or how fast you must travel, in which an object must achieve to "break" free of any gravitational pull.

• Sun - 617.7 km/s - 55 x that of Earth
• Mercury - 4.25 km/s
• Venus - 10.46 km/s
• Earth - 11.186 km/s
• Moon - 2.38 km/s
• Mars - 5.027 km/s
• Jupiter - 59.5 km/s
• Saturn - 35.5 km/s
• Uranus - 21.3 km/s
• Neptune - 23.5 km/s
• Pluto - 1.27 km/s
• Ceres - 0.51 km/s

To escape the solar system - ~ 1,000 km/s