Part of signal travelling along the ground is called the ground wave

1. 
   The speed of light very great, we cannot measure it by ordinary methods.
   
2. 
   Part of energy being changed into heat, is transformed into electrical energy.
   
3. 
   The size of the electrodes being increased, the current capacity also increases, the voltage output remaining the same.
   
4. 
   Thermostats are very sensitive to light, this property being very important.
   

1. 
   Testing a new receiver for the application in the system was the prime task of the laboratory.
   
2. 
   After investigating many materials engineers selected aluminum for constructing this device.
   
3. 
   I remember you having objected to the schedule.
   
4. 
   Charging by induction will be discussed in the next article.
   
5. 
   We know of all the substances consisting of atoms.
   

1. 
   The results obtained were of great importance.
   
2. 
   While compressing the gas we can turn it into liquid.
   
3. 
   The new building housing the laboratory will be located at some distance from the main building of the plant.
   
4. 
   This splitting of the hydrogen molecule is attended by the absorption of a large amount of energy.
   

Should the locomotive fail, it is easy to replace it with another. Failure of the motive power unit does not require taking the entire train out of service. Idle trains waste costly motive power resources. Separate locomotives enable costly motive power assets to be moved around as needed. Large locomotives can be substituted for small locomotives where the grades are steeper and more power is needed. Separating the motive power from payload-hauling cars enables one to be replaced without affecting the other. At times locomotives have become obsolete when their cars were not, and vice versa.

There are several advantages of multiple-unit trains compared to locomotives. Multiple-units are more energy efficient than locomotive-hauled trains and more nimble, especially on grades, as much more of the train’s weight is placed on driven wheels, rather than suffer the dead weight of unpowered coaches.

Many multiple-unit trains have cabs at both ends or arranged so that a set of cars has cabs at both ends, so that the train may be reversed without uncoupling/re-coupling the locomotive, giving quicker turnaround times, reducing crew costs, and enhancing safety. Multiple units normally have completely independent braking system on all cars, meaning the failure of the brakes on one car does not prevent the brakes throughout the train from operating safely.

1. 
   Without using superconducting materials it was impossible to perfect this system operation.
   
2. 
   He got a Capitol Hill having changed a tram for a bus.
   
3. 
   The new measuring instrument being developed in this laboratory will be tested by that engineer.
   
4. 
   Gagarin’s first space flight followed by many others was very important for the development astronautics.
   
5. 
   When heated, magnetized steel will lose its magnetism.
   

1. 
   Transistors being very sensitive to light, engineers use this property.
   
2. 
   The current distribution over the cross section of the conductor being non-uniform, the resistance increases.
   
3. 
   The condenser being placed in a direct currents circuit, the current will stop flowing.
   
4. 
   The fastest way to detect an artificial satellite is radio, largely used for that purpose.
   

1. 
   The new means of improving radio communication has been discovered by our engineers.
   
2. 
   Radiation is usually detected by measuring the amount of ionization.
   
3. 
   We knew of glass having been invented some hundreds years ago.
   
4. 
   He entered the room without noticing her.
   
5. 
   In making Bessemer steel, molten iron direct from the blast furnace is poured into the converter.
   

1. 
   We are proud of being students.
   
2. 
   The breaking of the circuit causes the magnetic field to disappear.
   
3. 
   Obtaining new data on the device sensitivity will be of great help for designers.
   
4. 
   There are several types of microphones being used, the most important of these being the dynamic microphone, the velocity microphone and the crystal microphone.
   

Вариант 4

1. 
   When produced in one tube, minimum grid voltage is produced in the other tube.
   
2. 
   The transmitter operating on the low frequencies was constructed by these students.
   
3. 
   The site of the city was chosen by G. Washington and was accepted by Congress in the act of 1790, establishing the Federal district of Columbia.
   
4. 
   New data being obtained are necessary for nature investigations.
   
5. 
   Negatively charged ions are attracted to the anode, positively charged ions are attracted to the cathode.
   

1. 
   Some radioactive materials have been found in nature, uranium being one of them.
   
2. 
   Chemistry and physics are interconnected sciences, any chemical change resulting in a physical change.
   
3. 
   The velocity, length and frequency of the wave are independent of each other, the frequency being equal to the velocity divided by the wavelength.
   
4. 
   The cyclotron may be regarded as a modification of the linear accelerator, the particles being transferred from one to the other at the proper instants by the action of a magnetic field.
   

1. 
   Iron and zinc plates are used for producing negative electrodes since these materials produce a high charge.
   
2. 
   He remembered once having read that at a very low temperature some metals become superconducting, having practically minimum specific resistance.
   
3. 
   He insisted on the question being reconsidered.
   
4. 
   The explanation lies in the product being more stable.
   
5. 
   Nothing could prevent Maria Curie from changing her course.
   

1. 
   Being built on the basis of transistors lasers are successfully used in technology.
   
2. 
   The energy of the body is its capacity for doing work.
   
3. 
   We know that the conversion of heat into chemical energy is reversed when the burning of coal converts chemical energy into heat.
   
4. 
   The charge of the electron being determined, it was easy to calculate its mass.
   

For the first years of the railroad industry freight was hauled on simple flatcars or early gondolas, which were essentially flatcars with short sides to keep the lading from rolling or falling off in transit (or in the case of bulk materials, to keep them confined). The early 1930s is when the true boxcar came to life (originally known as “house” cars), with one of its founders the Mohawk & Hudson Railroad (a very early subsidiary of the New York Central). By the latter part of that decade this new style of car was beginning to catch on across the rest of the industry as its versatility and value began to be realized.

1. 
   If arranged according to the atomic weights, elements show the periodicity of their properties.
   
2. 
   Being perfected the device operated successfully under all conditions.
   
3. 
   Building a network of transmitting stations in that region was of prime importance.
   
4. 
   The work of Rutherford followed by great help for understanding many natural phenomena.
   
5. 
   Some drawbacks of the reactor referred to in this article will be eliminated.
   

1. 
   The resistance of the body being high, small current flows through the body.
   
2. 
   Two bodies having potentials of 100 volts and 50 volts, a potential difference exists between them of 50 volts.
   
3. 
   A charge of one coulomb increasing the potential between plates by one volt, a capacitor had a capacity of one farad.
   
4. 
   The value of voltage was the same in all the elements of a parallel circuit, the value of current being different.
   

1. 
   Important results on the ionization were obtained by measuring those particles.
   
2. 
   The transistors are successfully used for transforming heat energy into electrical energy by means of thermal elements.
   
3. 
   Every student knows of copper being one of the first metals used by man.
   
4. 
   He improved the report by changing the end.
   
5. 
   In spite of its having been compressed, the gas returns to its original volume as soon as the applied force removed.
   

1. 
   Inductance is successfully provided with the silver coating and capacitance by the inner and outer surface of this silver with the porcelain as dielectric.
   
2. 
   He went away without waiting for reply.
   
3. 
   The main advantage of this instrument over the moving coil type instrument is that it is capable of measuring both alternating current and direct current.
   
4. 
   This article is worth reading.
   

While the perception has started to change in recent times for many years, even through the latter half of the 20th century, railroads have been quite stubborn about accepting new technologies or any change at all for that matter. So, when new oil companies began to spring up after oil reserves were discovered in the 1860s railroads were, not surprisingly, hostile to developing a new type of car to haul the commodity.

Prior to the 1870s the first true tank car began to take shape, transitioning from an early vertical vat-on-flat-car design to a horizontal iron tank which was mounted to a traditional flat car, very roughly similar to what is commonly used today. This new design allowed for much more of a commodity type to be shipped via one car and quickly became widely used, especially to haul crude oil. As the 20th century progressed the car was constructed of better materials. For instance, with the development of steel and welded seams the car was much stronger and thus could be built larger to haul much heavier loads. Also during the 20th century many more commodity types became available from eatable liquids to various oil products, which required differing types of tank cars to be built (such as those with interior glass-linings to accommodate edible commodities and chemicals). Over the last half-century or so the tank car's overall design has not changed significantly, with any alterations within the general design itself to accommodate various commodities (such as differing positions of the dome, walkways, and pressurized/non-pressurized railroad cars).