Why Do Power Lines Buzz?

The video explains the buzzing sounds from power lines and transformers. It covers the causes of transformer hum, including stray magnetic fields and magnetostriction, and discusses how the intensity of the hum is related to voltage. The video also explores corona discharge in power lines, which causes a buzzing sound and a bluish glow, similar to a miniature lightning strike.

What is the typical frequency range of the buzzing sound produced by power lines and transformers?

• 90 or 100 Hertz

• 70 or 80 Hertz

• 30 or 40 Hertz

• 50 or 60 Hertz

What causes the internal components of a transformer to vibrate, producing a buzzing sound?

• Electric resistance

• Chemical reactions

• Stray magnetic fields

• Thermal expansion

How does magnetostriction contribute to the buzzing sound in transformers?

• By altering the electric current

• By causing thermal expansion

• By expanding and contracting the iron core

• By changing the voltage

What phenomenon is responsible for the buzzing sound from overhead power lines?

• Thermal expansion

• Corona discharge

• Magnetostriction

• Electric resistance

What visual effect is associated with corona discharge around power lines?

• A soft bluish glow

• A yellow flash

• A bright red glow

• A greenish tint