# Question about Electric Generators (and Black emf)

• predentalgirl1
In summary, to construct an ac generator with a maximum emf of 400 V, a radius of 0.15 m, operating at a frequency of 60 Hz and using a magnetic field of 200 mT, approximately 75,000 loops will be needed.
predentalgirl1

An ac generator with a maximum emf of 400 V is to be constructed from wire loops (radius 0.15 m). It will operate at a frequency of 60 Hz and use a magnetic field of 200 mT. How many loops will be needed?

Given that,
Maximum emf = 400 V
Frequency (υ) = 60 Hz
Magnetic field = 200 mT
We have,
Maximum emf = Bnaω where ω = 2π υ
V = 200 x 10 ^-6 x n x π x (0.15)^2 x 2 π x 60
Therefore n = 400 x 7 x 100 x 100 x 7/200 x 10-6x 22 x 15 x 15 x 2 x 22 x 60
= 7.5 x 10^4

Therefore, approximately 75,000 loops will be needed to construct the ac generator with the given specifications. This number may vary depending on the precise values of the parameters used. I hope this helps!

Therefore, approximately 75,000 wire loops will be needed to construct the ac generator with the given specifications.

## 1. What is an electric generator?

An electric generator is a device that converts mechanical energy into electrical energy. It works by using a magnetic field and conductors to induce an electric current.

## 2. How does an electric generator work?

Electric generators work on the principle of electromagnetic induction. A coil of wire is rotated between two magnets, causing a magnetic field to cut across the coil, which induces an electric current.

## 3. What is black emf in relation to electric generators?

Black emf, also known as back emf, is a voltage that opposes the flow of current in an electric generator. It is caused by the rotating magnetic field cutting across the stationary conductors, creating a magnetic force that opposes the rotation of the generator.

## 4. How is black emf controlled in electric generators?

Black emf can be controlled by adjusting the strength of the magnetic field or the speed of rotation of the generator. This can be done by using different materials for the magnets or by changing the number of turns in the coil of wire.

## 5. What are some practical applications of electric generators?

Electric generators are used in a variety of applications, including power plants, wind turbines, hydroelectric dams, and portable generators. They are also used in everyday devices such as cars, motorcycles, and home appliances that require electricity to function.

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