4
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4.1.1. If Germanium had not been properly purified, it would not have suited for transistors.
4.1.2. They will be able to charge an object by induction unless they bring a charged body near it.
4.1.3. If the contact opens and closes very quickly, the amount of arcing will be greatly reduced.
4.1.4. If the whole expansion were performed in one cylinder this cylinder would have sufficient strength to withstand the high initial steam pressure.
4.1.5. If the members of the expedition used the camera for underwater photography, they might obtain valuable data.
䳺 , . .
4.2.1. If the ice in the Atlantic (to be) to be melted, it would raise ocean level by 50 meters.
4.2.2. Had I had this information before, I (to act) differently.
4.2.3. Unless you can deliver the machines by the 15th of July, we (to be compelled) to cancel the order.
4.2.4. I the weather (to be) so hot last month, the goods would not have gone bad during transportation.
4.2.5. Were he here, I (to know) it at once.
, 䳺 (The Absolute Participle Complex).
4.3.1. Alloying elements for making steel are nickel, chromium, manganese, nickel increasing strength and hardness of the steel..
4.3.2. No special cooling arrangements are necessary for small transformers, natural cooling being sufficient.
4.3.3. All drills are flame-proof constructions, the motor, the starting switch and the cable entry having separate flame-proof enclosures.
4.3.4. With the experiments having been carried out, we started new investigations.
4.3.5. The forces imposed upon the bridge being determined, it is possible to take into account the bearing capacity of stratum..
, , 䳺 (The Absolute Participle Complex).
4.4.1. , .
4.4.2. , .
4.4.3. , ..
, ᒺ (Complex Object).
4.5.1. We know them to have had an interesting report.
4.5.2. I saw the threading tools put into the box.
4.5.3. I did not see him inspect the engine when I came into the lab.
4.5.4. He likes people to tell truth.
4.5.5. She noticed him closing the bonnet.
, ᒺ (Complex Subject). .
4.6.1. The above mentioned reactions were certain to proceed violently.
4.6.2. The goods are unlikely to be unloaded today.
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4.6.3. Passenger traffic is expected to continue increasing.
4.6.4. The UNO can be said to have been founded to maintain international peace and security.
4.6.5. The idea of space flight appears to have been attracting the attention of the people since the remotest times.
, ᒺ (Complex Object) ᒺ (Complex Subject).
4.7.1.1. , .
4.7.1.2. , .
4.7.1.3. , , .
4.7.1.4. ³, .
4.7.1.5. , .
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Batteries
An electrical battery is a combination of one or more electrochemical cells used to convert stored chemical energy into electrical energy. Since the invention of the first voltaic pile in 1800 by Alessandro Volta, the battery has become a common power source for many household and industrial applications.
A battery is a device that converts chemical energy directly to electrical energy. It consists of a number of voltaic cells; each voltaic cell consists of two half cells connected in series by a conductive electrolyte containing anions and cations. One half-cell includes electrolyte and the electrode to which anions (negatively charged ions) migrate, i.e., the anode or negative electrode; the other half-cell includes electrolyte and the electrode to which cations (positively charged ions) migrate, i.e., the cathode or positive electrode. The electrodes do not touch each other but are electrically connected by the electrolyte.
There are two types of batteries: primary batteries (disposable batteries), which are designed to be used once and discarded when they are exhausted, and secondary batteries (rechargeable batteries), which are designed to be recharged and used multiple times. Miniature cells are used to power devices such as hearing aids and wristwatches; larger batteries provide standby power for telephone exchanges or computer data centers. Primary batteries can produce current immediately on assembly. Disposable batteries are intended to be used once and discarded. These are most commonly used in portable devices that have low current drain, are only used intermittently, or are used well away from an alternative power source, such as in alarm and communication circuits where other electric power is only intermittently available. Secondary batteries must be charged before use; they are usually assembled with active materials in the discharged state. Rechargeable batteries or secondary cells can be recharged by applying electrical current, which reverses the chemical reactions that occur during its use.
The oldest form of rechargeable battery is the lead-acid battery. This battery is notable in that it contains a liquid in an unsealed container, requiring that the battery be kept upright and the area be well ventilated to ensure safe dispersal of the hydrogen gas produced by these batteries during overcharging. The lead-acid battery is also very heavy for the amount of electrical energy it can supply. Despite this, its low manufacturing cost and its high surge current levels make its use common where a large capacity (over approximately 10Ah) is required or where the weight and ease of handling are not concerns.
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1. Who invented the first batteries?
2. How many types of batteries are there?
3. What is the oldest type of the secondary batteries?
4. Can you name advantages and disadvantages of lead-acid batteries?
5. How is the battery constructed?
