# Magnetic field in a tv set

• shaffeb
In summary, the problem involves finding the maximum magnetic force experienced by an electron accelerated through a potential difference of 19kV and passing through a 0.28T magnetic field. Using the equations F=qvBsin(theta) and E=-V/x, the maximum force can be found by solving for F when sin(theta)=1, q=e=charge on electron, and the known values of speed and magnetic field strength.

## Homework Statement

In a television set, electrons are accelerated from rest through a potential difference of 19kV. The electrons then pass through a 0.28T magnetic field that deflects them to the appropriate spot on the screen. Find the magnitude of the maximum magnetic force that an electron can experience.

F=qvBsin(theta)
E=-V/x

## The Attempt at a Solution

I am trying to figure out where the potential difference comes into play but am not sure because E and x are not given. Any hints would be great, thanks.

When the electrons are accelerated across the potential given, they gain kinetic energy =eV, where e is the charge on the electron. Using this, you can find the speed of the electron once it leaves the electric field and enters the magnetic field.

Then, the maximum magnetic force will be when sin(theta)=1. The speed you know, the magnetic field strength you know, and q=e=charge on electon. Solve for F.

I would approach this problem by first understanding the basic principles of electromagnetism. In this case, we are dealing with the interaction between an electric field and a magnetic field.

The potential difference of 19kV is the electric potential difference that accelerates the electrons from rest. This creates a uniform electric field within the television set. As the electrons pass through this electric field, they gain kinetic energy and are then directed towards the screen.

Once the electrons enter the magnetic field of 0.28T, they experience a magnetic force due to the interaction between their velocity (v) and the magnetic field (B). The angle between the two vectors is 90 degrees, as the electrons are moving perpendicular to the magnetic field. Therefore, we can use the equation F=qvB to calculate the magnitude of the maximum magnetic force.

To find the value of q, we can use the relationship between electric potential difference (V) and electric field (E), which is given by E=-V/x. Since we are dealing with a uniform electric field, we can assume that E is constant and solve for q.

Plugging in the given values, we get E=-19kV/x=19,000V/x. Since we know that the electric field is equal to the potential difference divided by the distance (E=V/x), we can rearrange the equation to solve for x. This gives us x=19,000V/E.

Now, we can substitute this value of x into the equation F=qvB to calculate the maximum magnetic force. We know that q is the charge of an electron (1.602 x 10^-19 C) and v is the velocity of the electron, which we can calculate using the kinetic energy gained from the potential difference.

Once we have all the values plugged in, we can solve for F and get the magnitude of the maximum magnetic force that an electron can experience in the television set.

In conclusion, the potential difference of 19kV plays a crucial role in accelerating the electrons and creating a uniform electric field, which then interacts with the magnetic field to deflect the electrons and create the image on the screen. By understanding the basic principles of electromagnetism and using the appropriate equations, we can solve for the magnitude of the maximum magnetic force experienced by the electrons in the television set.

## 1. What is a magnetic field in a TV set?

A magnetic field in a TV set is a region in which a magnetic force can be detected. It is created by the flow of electricity through the TV's circuitry and is essential for the proper function of the TV.

## 2. How is the magnetic field produced in a TV set?

The magnetic field in a TV set is produced by the flow of electricity through the TV's circuitry. This creates a magnetic force that interacts with the electrons in the TV's screen, producing the images we see.

## 3. Is the magnetic field in a TV set harmful to humans?

No, the magnetic field in a TV set is not harmful to humans. It is a low-level field and does not produce enough energy to cause any harm. However, it is recommended to maintain a safe distance from the TV to avoid eye strain.

## 4. Can the magnetic field in a TV set be manipulated?

Yes, the magnetic field in a TV set can be manipulated. This can be done by adjusting the TV's settings or by using external magnets near the TV. However, doing so may affect the TV's performance and is not recommended.

## 5. Why is a magnetic field necessary in a TV set?

A magnetic field is necessary in a TV set because it is essential for creating the images we see on the screen. Without a magnetic field, the electrons in the TV's screen would not be able to move and produce the images, rendering the TV useless.