Amazing knowledge

Chapter 13 Electronic Genesis: If you can’t keep up with the changes, you’re an idiot
* Is mobile phone radiation as terrible as it is said in the legend?

Practicality: ★★★★★

Knowledge: ★★
Interesting: ★★★

Mobile phones have become an indispensable tool in our daily life, but mobile phones have radiation, and it is said that the radiation value is very high.Is mobile phone radiation really that scary?

Water pollution, air pollution, and noise pollution have always been the three major environmental pollutions that plague humans. However, with the widespread use of electronic products, electromagnetic radiation has become the fourth largest environmental pollution that humans need to face.

The mobile phones, computers, induction cookers, and microwave ovens that we can come into contact with in our daily life all have a certain amount of radiation. How to reduce the radiation in our lives and how to protect ourselves from heavy radiation has become a hot topic.

But in fact, these ionizing radiation is not so terrible, normal use will not affect the human body.

Even the ionizing radiation emitted by the mobile phones that we carry close to our bodies and almost never leave our bodies is within the safe range. As long as the mobile phones are used correctly and regulatedly, the radiation from mobile phones is only mediocre, so there is no need to worry about it.

But this "correct use" of mobile phones definitely does not include talking on the phone, especially when the signal is not good.

Our mobile phone has a self-adjusting function. When the environmental signal is not good, the mobile phone will automatically increase its own power in order to improve the signal quality.

In order to be able to better search for the signal emitted by the base station, the mobile phone will work harder. In this case, the power consumption of the mobile phone will increase greatly, and the radiation will also increase.

If the signal is not good, it is better to avoid making calls as much as possible. Although the radiation power of mobile phones produced by regular manufacturers is within the standard range, overloading the mobile phone for a long time is also a kind of harm to the mobile phone.

The final word: Although there is mobile phone radiation, it does not need to be so concerned by everyone.I just hope that everyone will buy mobile phones produced by regular manufacturers, and avoid talking on the phone when the signal is not good.

*Is it possible to eavesdrop on calls by copying the SIM card with the mobile phone number?
Practicality: ★★★★★

Knowledge: ★★★★
Interesting: ★★★

I heard that now that the technology is advanced, you only need to simply copy the SIM card with the mobile phone number to listen to other people's calls. Is eavesdropping really that simple?

If this is true, the first one not to agree is the three major operators!This is simply questioning the authority of operators and treating them as nothing. If SIM cards are so easy to copy, mobile phone communication standards cannot be used today!

Although the SIM card is small, there is still a lot of information stored in this small card. SIM card serial number, PIN password, PUK password, international mobile subscriber identification code, authentication key, SIM card can also store a small amount of text messages and contacts.With the advancement of SIM card technology, the memory of the SIM card is also expanding.

There are so many things stored in the SIM card, but there is no mobile phone number! From production to sale, the SIM card has nothing to do with the mobile phone number.The reason why we can use the SIM card to make calls and send text messages is that when we buy the SIM card, the operator will "bind" the mobile phone number we choose with the SIM card, and store the information stored in the SIM card with us in the database. The relevant number is registered and then stored.

When we make a call, the SIM card will initiate a request to the operator, and the operator will agree to our call request after passing a series of "identifications", and the call can be established.

It is very difficult to copy the SIM card, and even if the SIM card is copied, it is impossible for the two cards to be online at the same time, because the "authentication" behavior initiated by the operator cannot be copied. If there is a conflict between the two cards, you must If one party is forced to go offline, it is impossible to be online at the same time.

The final word: first of all, the SIM card cannot be copied by the mobile phone; and even if the SIM card is copied, it is impossible for the two cards to be online at the same time.Therefore, eavesdropping in this way will not work.

* Can I answer calls while the phone is charging?
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Knowledge: ★★★★
Interesting: ★★★

There is a news that someone answered the phone while the phone was charging, and was shocked to death in the end. Is it true that the phone cannot answer the phone while it is charging?

Actually, this is a misunderstanding.The standard voltage we use is 220V. This voltage value can indeed kill people instantly, but our charger does not simply transmit the 220V voltage to the mobile phone.

The mobile phone charger has a part with a standard voltage of 220V and a transformer part that can convert high voltage into low voltage. The transformed low voltage is the part that supplies power to the mobile phone.The current chargers in the market generally have an output voltage and current of "5V, 1A". Some chargers may use an output current of 2A in order to be able to charge quickly, but the output voltage will basically not change.

The voltage of 5V will not cause harm to the human body. Only when the voltage exceeds 36V, it is possible to overcharge the human body and cause certain damage.So even if the shell of the charger is damaged, causing leakage, what we can feel is only the output voltage of 5V, and will not directly contact the 220V high voltage.

Because the transformer in the charger is very close to the high-voltage part, it is almost impossible for the high-voltage part to leak electricity. The only possibility of causing high-voltage leakage is that the transformer is damaged, and the high-voltage and low-voltage parts are directly connected, but If this is the case, the first thing we can't bear is our mobile phone. We have no chance to answer the phone at all, because the mobile phone has been burned by high-voltage electricity.

The final word: If the quality of the charger or battery of the mobile phone is not good enough, it may indeed cause an explosion due to poor heat dissipation, but it is impossible to be electrocuted to death due to making and receiving calls while charging.

*Can't an iPhone be charged with an iPad charger?

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Knowledge: ★★
Interesting: ★★★

Every time a new Apple product comes out, it will cause "fruit fans" to go crazy, but some people say that iPhone and iPad chargers cannot be used together. Is there any "gap" between products of the same brand?What exactly is going on?

The reason why there are such rumors, in the final analysis, is because the chargers of iPhone and iPad are really different!The parameters of the two are slightly different. The rated current of the iPhone charger is 1A, while the rated current of the iPad charger is 2.1A. Because of this difference, many people have the above misunderstanding, thinking that if you use the iPad charger If the charger charges the iPhone, it may damage the iPhone due to the high current.

In fact, you really don’t have to worry, whether it’s a 1A charger or a 2.1A charger, the working principle is the same, they both convert the standard high voltage of 220V into a low voltage of 5V.

As for the amount of current flowing through the charger, this actually depends more on the load of the charger, that is, the device charged by the charger.

After the charger is connected to the load, it will determine how many amperes of current flow through the charger according to the needs of the load. The charger itself has an overload protection circuit, which is used to protect the load.Because the charger will try its best to meet the needs of the load, as long as the load needs it, the charger will try to provide current as much as possible, but if the charger provides the maximum current it can withstand, it still cannot meet the needs of the load, the charger will also It can only maintain the maximum current output all the time.If the output current is too large, the charger will activate the protection device and automatically cut off the power.

Therefore, if the wrong charger is used and the load is overloaded, the charger will first cut off the power in order to protect itself.

The final word: Whether it is an iPhone or an iPad, their chargers are universal, and the output current will not damage the phone.

*Is it true that surfing the Internet on a public network will endanger account security?
Practicality: ★★★★★

Knowledge: ★★★★
Interesting: ★★★

With the rise of wireless networks, Wi-Fi has gradually become an inseparable thing for us. Having a mobile phone without Wi-Fi is like eating without chopsticks. However, it is said that Internet accounts in public places are very insecure. Using public Internet accounts It is possible that your account will be stolen by others. Is the security of public network accounts strong?

To be honest, for network engineers, as long as everyone uses a public network account, it is really not difficult to steal other people's account names and passwords.

But what can be stolen is only some unencrypted information, such as our online banking and Alipay passwords, which are more important and have been encrypted multiple times, generally cannot be stolen through public network accounts.

The process of our surfing the Internet is actually the process of sending and receiving various data packets. When we log in to the account and enter the password, of course we also need to package and send this information to the server. As long as we "catch" them during the transmission of the data packets, we will Account information and passwords can now be easily obtained.

However, our bank accounts, Alipay accounts and other accounts involving money are heavily encrypted, and each bank has different authentication methods, some use electronic password cards, and some use USB shields. Account passwords are very difficult.

It is not easy for others to steal your bank account information, but the premise is that you do not fall into the trap of others. Some phishing websites specialize in stealing account names and passwords. If you enter your information on a phishing website, That would really be stolen.

The final word: The Internet is an open and interconnected environment. There is no absolute security and privacy here. Everything you do and every trace you leave on the Internet will be recorded and stored in the server. in a certain corner.

*Has the U disk really shrunk?
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Knowledge: ★★★★
Interesting: ★★★★
Many people may wonder, every time you buy a USB flash drive, plug it into your computer and see that it is always smaller than the capacity marked on the USB flash drive. What is the reason for this? Has the U disk shrunk?
This is not because the U disk has shrunk, but because the data is not equal due to the inconsistent measurement unit.

在计量单位的换算上面，我们比较熟悉的应该就是10倍或是100倍、1000倍这样的换算倍数，一般计量单位之间都是十进制的，比如说1分米=10厘米、1厘米=10毫米。

Therefore, in the international standard system of measurement units, 1K=1000, 1M=1000K, 1G=1000M, this is a relatively highly accepted conversion method.

But in the world of computers or USB flash drives, the conversion method has changed.Because the data storage in the computer is all 1 or 0, it is a pure binary world, each bit is called a bit, that is, bit, 1 byte = 8bit.

In our inertial thinking, 1 byte = 10bit makes more sense, but this is the difference between the binary world and the decimal world.

Manufacturers of U disks also follow the inertial thinking. The 1G capacity they mark is actually 1000M, which is 109byte=1 bytes.

But when the USB flash drive is plugged into the computer, the computer still operates according to the internal binary rules, so that the computer can process data at an optimal speed.

Therefore, in a computer, 1KB=210B, 1MB=210KB, 1GB=210MB=210B=1bytes.

Manufacturers and computers have different calculation methods for the capacity of the U disk. One uses the decimal system of international conventions, and the other uses the most efficient binary system in the calculation, so the U disk will "shrink" after it is inserted into the computer. The phenomenon is mainly due to the unequal information and the difference in unit conversion, not because the merchants are falsifying.

The final word: U disks produced by regular manufacturers are basically standard in capacity, but the unit conversion methods used by computers or manufacturers are different, so there will be "shrinkage".

*Is it true that computer viruses will invade human brains in the future?
Practicality: ★★★

Knowledge: ★★
Interesting: ★★★

With the super-high-speed development of computer technology, our life has been filled with all kinds of intelligence. Some scientists even predict that computer viruses will invade human brains in the future. Is this possibility really possible?
The British "Daily Mail" once published a report by relevant researchers from the Singularity University Research Institute in the United States. The report stated that with the development of synthetic biology, humans have been able to regulate the form of biological expression by controlling genes. If genetic engineering continues to develop, hackers are very likely to design new virus programs, implant them into DNA as living bacteria, infect genes, and thus control human thinking.

In the future, human DNA will also appear in a form of language, and we will be able to decode, reorganize, and transform it into what we want.

Does this sound scary? Our thinking may be completely out of our control. If this prophecy comes true, then this will be the biggest biochemical crisis in the history of human development.

However, this matter is still very far away from us. After all, so far, computer programs are just a bunch of codes, not biological viruses. According to the internal language of the computer, the two should be completely incompatible.

The final word: Maybe one day in the future, computer programs can be transformed into biological viruses, and biological viruses can be synthesized by code, then maybe humans will really be invaded by computers, but that day should be far away.

*Why are the earphone cables always tangled together?
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Knowledge: ★

Interesting: ★★★

When a person is lonely, taking out the earphones and listening to music quietly for a while may relieve our emotions, but every time the earphones are taken out, the messy look makes many people crazy. Why are the earphone cables always entangled? Like a mess?
First of all, the material of the headphone cable should be considered. Inside the headphone cable is a metal wire that can transmit signals, but the outside is wrapped in plastic, which is an elastic and thermoplastic material.The headphone cable is slender and slender, and the ratio of length to width is seriously out of balance. Such a structure itself is unstable and is very prone to bending.

Moreover, the bending of the plastic outside the earphone is only a case, and sometimes the earphone wire will move around the central axis around the wire inside the wire.

Another point is that the earphones not only have earphone cables, but also two earplugs and a socket. The quality of these three is much larger than that of the earphone cables, and the density is completely incomparable. When we put the earphones on the body, the three The relatively high-quality part will walk back and forth "willfully", but the movement of the headphone cable is very small. This contrast also makes the headphone cable always appear in a tangled state.

The final word: Whether it is the structure of the earphones or the material of the earphones, they are the reasons why the earphone wires are easy to get entangled. If you want the earphones to "stay still", the best way is to limit their range of motion. Pack them into smaller spaces.

*Why are computer keyboards not in alphabetical order?
Practicality: ★★★★★

Knowledge: ★★
Interesting: ★★★

With the popularity of computers, everyone should have seen the keyboard, but have you noticed that the keys on the keyboard are not arranged in the order of 26 letters, why is this?

In fact, when this keyboard arrangement first came out, the designer said that this keyboard typing speed is faster.But the fact is completely opposite, because people type too fast, the keyboards arranged in order are easy to get stuck, so they mess up the order of the keyboards, slow down people's typing speed, and let the keyboards have time to respond, so that The case of Caton appears a little less.

After the earliest keyboards were designed and manufactured, people quickly discovered a problem. Because of the backward technology, it took a long time for the keyboard to rebound after being pressed. If people type fast, the keys on the keyboard are very It is easy to twist together, causing the keyboard to "strike".

After the engineers discovered this problem, they also wanted to innovate the technology and improve this problem for a while.The engineers thought that if they completely separate the characters that people commonly use and make them "separate from each other", people will inadvertently slow down when typing, and the situation of stuck keys will be improved, so they messed up the order. And so the keyboard was born.

Nowadays, technology can completely solve the problem of slow button rebound, but people seem to have become accustomed to the disordered arrangement of keys, so until now, the keyboards we see and use are still arranged in random order.

The final word: The original intention of the out-of-order keyboard design is to slow down people's typing speed and buy some time for the rebound of the keys, but this keyboard arrangement has continued to this day.

* Is online shopping greener?

Practicality: ★★★★★

Knowledge: ★★
Interesting: ★★★★
With the development of Internet technology today, we can easily buy what we want without leaving home. Some people say that online shopping is not only convenient and simple, but also energy-saving and environmentally friendly. Let’s take a look at how environmentally friendly online shopping is.

People who think that online shopping is more environmentally friendly, their idea should be that online shopping saves time-consuming and laborious activities such as shopping in shopping malls. If everyone shops online, shopping malls that consume a lot of energy may be closed, and online shopping that does not require physical stores seems real. It is more energy-saving and environmentally friendly.

But everyone only considers that shopping malls consume a lot of energy. Have you ever thought that online shopping also requires many steps?We only need to browse the information of some products on the Internet, finally decide which product to buy, and then pay and wait for the goods to be received. However, the merchants need to deliver the goods to us from the place of delivery for thousands of miles.

In most cases, online shopping goods need to be transported farther than the distance we go to the mall to purchase, and the transportation cost along the way is roughly estimated to be not small.

Furthermore, we need servers to maintain our online shopping. Without the support of servers, data centers and network terminals, let alone online shopping, we can’t even access the Internet, and the maintenance of servers and data centers also consumes a lot of energy.

In Washington, USA, there is the largest data center in the world. The data center needs to pay 45 billion US dollars in electricity costs every year. The power consumption of such a data center even exceeds 1% of the United States. The combined power consumption of all TVs in the United States Nothing compares to the power consumed by this data center.

The final word: For us personally, online shopping is indeed environmentally friendly, but from a macro perspective, online shopping does not consume much less energy than traditional shopping models.

*Why is the password of the bank card six digits?

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Knowledge: ★★★

Interesting: ★★★

Regardless of whether it is the Industrial and Commercial Bank of China, the Agricultural Bank of China or the Bank of China, the bank card passwords are all six digits. Why is this?If you add a few more digits, isn't the security factor of the password higher?
Longer passwords are indeed more secure, but people's memory is limited, especially for some elderly people, too complex passwords may be a burden for them, and the security factor is so high that they can hold Cardholders themselves can't remember their passwords.In contrast, a six-digit password can achieve a balanced state. The difficulty of the password will not be too low, but the requirements for memory will not be too high.

When designing the password at the beginning, the designers combined various factors and chose six digits as the bank password. This habit has been used until now.

In this process, the bank may have also thought about increasing the length of the password and appropriately increasing the complexity of the password to increase the safety factor, but if this idea is really implemented, it will be very difficult for the bank. Huge and difficult to implement.

In the process of modification, a major mistake may occur if you are not careful, and if you modify the password in this way, it is likely to give criminals an opportunity, so the bank has not taken action for a long time. Still active in banking.

The final word: the six-digit password is designed after comprehensive consideration of security and memory difficulty. Although some people think that the six-digit password is too simple, the bank's security system is also very strict. As long as you are careful, we will Your bank account is still safe.

(End of this chapter)