Electromagnetic waves - antennas

In summary, the conversation is about using a magnetic dipole to detect an electromagnetic wave and finding the amplitude of the induced emf in a coil. The equation \varepsilon_m = N \omega A B is mentioned as a possible solution, but the application of Faraday's law and time dependence of magnetic induction are also important factors to consider.
  • #1
evan4888
11
0
I just need a little direction to get started on this problem.


A magnetic dipole is uded to detect an electromagnetic wave. The antenna is a coil of 50 turns with radius 5.0 cm. The EM wave has frequency 870 kHz, electric field amplitude 0.50 V/m, and magnetic field amplitude 1.7 x 10^-9 T.

What is the amplitude of the induced emf in the coil?
 
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  • #2
I think you might need a review of the Faraday's electromagnetic induction law.

Daniel.
 
  • #3
I will need a little more guidance than that. I am thinking that I need to find the emf, but I am not sure how I could do that without a variable of time.

Or would I just use the equation:

[tex] \varepsilon_m = N \omega A B [/tex]
 
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  • #4
That's the right equation indeed and it follows really nicely, if you apply Faraday's law correctly and assume, for simplicity a cosinusoidal time dependence of the magnetic induction.

Daniel.
 

FAQ: Electromagnetic waves - antennas

What are electromagnetic waves?

Electromagnetic waves are a form of energy that consist of both an electric field and a magnetic field oscillating at right angles to each other. They are produced by the acceleration of electrically charged particles and can travel through empty space as well as through various materials.

How do antennas work?

Antennas work by converting electrical energy into electromagnetic waves and vice versa. They consist of conductive metal elements that are designed to resonate at a specific frequency, allowing them to transmit or receive electromagnetic waves efficiently.

What is the difference between transmitting and receiving antennas?

Transmitting antennas are designed to convert electrical signals into electromagnetic waves, while receiving antennas are designed to capture and convert incoming electromagnetic waves into electrical signals. Both types of antennas can be used for communication purposes.

What factors affect the performance of an antenna?

The performance of an antenna can be affected by various factors, including its size, shape, and orientation. The frequency of the signal being transmitted or received also plays a significant role, as well as the materials used in the construction of the antenna.

How are electromagnetic waves used in everyday life?

Electromagnetic waves have a wide range of applications in everyday life, including communication (radio, television, and cellular signals), heating and cooking (microwaves), medical imaging (X-rays), and many more. They also play a crucial role in technologies such as radar, GPS, and satellite communications.

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