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A thermal power plant produces electric power of 600kW at 4000 V, which is to be transported to a place 20 km away from the power plant for consumers’ usage. It can be transported either directly with a cable of large current carrying capacity or by using a combination of step-up and step-down transformers at the two ends. The drawback of the direct transmission is the large energy dissipation. In the method using transformers, the dissipation is much smaller. In this method, a step-up transformer is used at the plant side so that the current is reduced to a smaller value. At the consumers’ end, a step-down transformer is used to supply power to the consumers at the specified lower voltage. It is reasonable to assume that the power cable is purely resistive and the transformers are ideal with power factor unity. All the currents and voltages mentioned are rms values. If the direct transmission method with a cable of resistance 0.4 Ω km−1 is used, the power dissipation (in %) during transmission is

20 b) 30 c) 40 d) 50 Solution: b) 30 Explanation: R=0.4*20 = 8Omega... View Article

47 in binary is equal to

Solution: Given number is 47. To convert a decimal number to binary, we divide it successively by 2, until quotient is 0. Keep the whole part... View Article

What is x squared?

Solution: x squared is a notation that is used to denote x multiplied by itself. x squared symbol is x2. Here x is the base and 2 is the... View Article