Which of the practices will lead to losses in electrical power transmission?
A. Using transmission cables of large diameter
B. Transmitting at high voltage and low current
C. Transmitting at relatively low voltage and high current
D. Using a step-up transformer at the production end
i^2 R = power lost to heating resistance
high current ---> high loss
so for given power in = V i you want high voltage and low current to MINIMIZE losses. That is why long distance power lines are high voltage and are stepped down in your local neighborhood for safer lower voltage.
So according to your explanation, transmitting at high voltage and low current will lead to losses in electrical power transmission right? Which is option B. Though am not a science student rather Art but the question appeared on my hnd aptitude test, so I want to know the correct answer.
The correct answer is C. Transmitting at relatively low voltage and high current will lead to losses in electrical power transmission.
To understand why this is the case, we need to consider the concept of power transmission and the factors that affect its efficiency.
Power transmission involves transferring electrical energy from a power generation source to consumers. The two main factors that affect power transmission efficiency are voltage and current.
According to Ohm's law (V = I * R), where V is voltage, I is current, and R is resistance, the power loss in a transmission line is given by the equation P = I^2 * R, where P is power loss. From this equation, we can see that power loss is directly proportional to the square of the current flowing through the transmission line.
Therefore, by transmitting at relatively low voltage and high current (option C), the current is increased, resulting in higher power losses. This is because higher currents encounter more resistance in the transmission lines, leading to greater power dissipation in the form of heat. Additionally, higher currents can also cause more voltage drop, reducing the effectiveness of power transmission.
In contrast, transmitting at high voltage and low current (option B) is a more efficient method of power transmission. Higher voltages reduce the current required to transmit a given amount of power, resulting in lower power losses. This is known as "voltage step-up" and is commonly used in power transmission networks.
Using transmission cables of large diameter (option A) does not lead to losses in power transmission. Larger-diameter cables can help reduce resistance and, thus, power losses. However, it does not directly address the voltage and current relationship or the factors highlighted in the other options.
Using a step-up transformer at the production end (option D) actually helps to improve power transmission efficiency. Step-up transformers increase the voltage while decreasing the current, allowing for more efficient long-distance transmission of electricity.
In summary, B and D are practices that help mitigate losses in electrical power transmission, while A and C contribute to higher power losses. Therefore, the correct answer is C. Transmitting at relatively low voltage and high current.