Induced emf between theh ends of an antenna

In summary, the problem involves a car with a vertical radio antenna driving east at a speed of 25 m/s. The Earth's magnetic field at the location has a magnitude of 5.9 * 10-5 T and points northward at 72 degrees below the horizontal. The question asks whether the top or bottom of the antenna is at a higher potential and to find the induced emf between the ends of the antenna. To solve this, the formula E = Bvl is used, where E is the induced emf, B is the component of the Earth's magnetic field perpendicular to the antenna, v is the velocity of the car, and l is the length of the antenna. The answer obtained using this formula is
  • #1
mike1234
5
0

Homework Statement


A car with a vertical radio antenna 85cm long drives due east 25 m/s. The Earth's magnetic field at this location has a magnitude of 5.9 * 10-5 T and points northward, 72 degrees below the horizontal. a) Is the top or the bottom of the antenna at the higher potential? b) Find the induced emf between the ends of the antenna


Homework Equations


E=Bvl


The Attempt at a Solution



I started with E=Bvl where E=5.9 *10-5T *(cos 18 or 108 not sure)* 25m/s * .85m and get a value of 1.19mV with cos 18. however not sure should I use 108 instead but don't know the reasoning help someone
 
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  • #2
does no one know the answer to this question
 
  • #3
Hint: To use that formula, you need the component of B perpendicular to the antenna.
 

FAQ: Induced emf between theh ends of an antenna

1. What is induced emf between the ends of an antenna?

Induced emf (electromotive force) is an electrical phenomenon that occurs when a changing magnetic field creates an electric field in a conductor, resulting in the production of an electric current. In the case of an antenna, induced emf refers to the voltage generated between the two ends of the antenna due to the presence of a changing electromagnetic field.

2. How does induced emf work in an antenna?

An antenna is made up of a conductive material, such as copper or aluminum, which allows for the movement of electrons. When an electromagnetic wave, such as a radio wave, passes through the antenna, it creates a changing magnetic field. This changing magnetic field induces an electric field in the antenna, causing electrons to move and resulting in an electric current.

3. What factors affect the magnitude of induced emf in an antenna?

The magnitude of induced emf in an antenna is affected by several factors. These include the strength and frequency of the electromagnetic wave, the length and diameter of the antenna, and the material and shape of the antenna. A larger antenna with a higher frequency and a stronger electromagnetic wave will typically result in a higher induced emf.

4. How is induced emf used in practical applications?

Induced emf in an antenna is used in various practical applications, such as in radio and television broadcasting, wireless communication, and radar systems. By manipulating the magnitude and direction of the induced emf, information can be transmitted through the electromagnetic waves and received by other antennas, allowing for communication over long distances without the need for physical connections.

5. Can induced emf be harmful to humans?

Induced emf in an antenna is typically not harmful to humans. The magnitude of induced emf in everyday devices is relatively low and poses no health risks. However, in some cases, such as in high-powered radio or radar systems, induced emf can be strong enough to cause electric shocks or interfere with pacemakers and other electronic devices. Safety precautions should always be taken when working with high-powered electromagnetic fields.

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