# Question Video: Understanding the Transmission of Electrical Power across Large Distances Physics

What type of device can be used to increase the potential difference of electricity supplied to the national grid so as to increase the power transmitted while reducing the energy lost to the surrounding environment? [A] A solenoid [B] A diode [C] A capacitor [D] A transformer [E] A rectification circuit

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### Video Transcript

What type of device can be used to increase the potential difference of electricity supplied to the national grid so as to increase the power transmitted while reducing the energy lost to the surrounding environment? A) A solenoid, B) a diode, C) a capacitor, D) a transformer, E) a rectification circuit.

To solve for the answer, we can work through what each of these five devices is and what it does. First, a solenoid: a solenoid is a coil of wire that’s an element of a circuit. When we pass current through a solenoid, it acts like a magnet. A solenoid creates a magnetic field within its coils when current runs through it. But it doesn’t increase the potential difference of electricity in the circuit it’s a part of.

A diode is another type of circuit element. A diode is designed to let current pass much more easily through it one way then the other way through the circuit. A diode also doesn’t increase the potential difference of electricity in the circuit.

Moving on to a capacitor, a capacitor is a circuit element used for storing up charge and thereby energy. However, the mechanism of the capacitor means that it can’t add or increase potential difference in the circuit it’s a part of. This also is not the type of device we want.

We then consider a transformer. A transformer is a device used to connect two current loops. In connecting these loops and varying the number of turns each loop makes around the transformer core, this device is able to step up or increase or step down or decrease the potential difference or the voltage in the import or primary current loop. This means that if the potential difference in the first current loop is 𝑉 one, then the transformer can convert that potential difference to a different value either higher or lower than 𝑉 one, depending on the geometry of its setup. A transformer then is exactly the kind of device used to increase electricity potential difference. This is the device we want to use.

To round out our list, let’s consider a rectification circuit. The purpose of a rectification circuit is often to convert alternating current AC to direct current DC. In that process though, it doesn’t necessarily increase the potential difference of the electricity running through the circuit.

All this to say the transformer is the device we will choose.