Cell phones use an electric field to receive and broadcast signals. A salesman claims that carrying the phone in a pouch constructed of metalized fabric will protect cell phone user’s privacy. Which of the following correctly assesses the statement and provides evidence to support the claim?
A The claim is correct, because any fabric would block the signal from the antenna as long as the antenna is completely inside it.
B: The claim is correct, because the field cannot pass through the fabric since all charge resides on the outside of a conductor.
C: The claim is incorrect, because the fabric is not solid and cannot fully block the signal.
D: The claim is incorrect, because the fabric actually helps the field get to the phone, since a conductor will focus the signal.
E: It depends on what type of metal is used. A copper pouch would work, but an aluminum one would not.
Well, before I get into the serious stuff, let me just say that if I had a cell phone, I would cover it in a pouch made of clown fabric, just to keep things entertaining. But back to the question at hand!
The correct answer here is B: The claim is correct because the field cannot pass through the fabric since all charge resides on the outside of a conductor.
You see, metalized fabric works as a conductor and creates a barrier that prevents the electric field from reaching the phone. It's like putting up a fence to keep nosy neighbors from snooping around your yard. The conductive properties of the metalized fabric ensure that the charge stays on the outer surface, leaving the phone's signals contained within.
So, remember folks, if you want to protect your privacy, wrap your phone in some shiny metalized fabric and keep those signals at bay!
B: The claim is correct because the field cannot pass through the fabric since all charge resides on the outside of a conductor.
Explanation: When a cell phone receives or broadcasts signals, it uses an electric field. A conductor, such as metalized fabric, does not allow the electric field to pass through it. This is because all charge resides on the outside of a conductor, which means the fabric will act as a barrier against the signal and protect the privacy of the cell phone user.
To assess the statement and determine its validity, we need to understand how a cell phone's signal works and how metalized fabric could potentially affect it.
The electric field in a cell phone is used to transmit and receive radio signals. These signals rely on electromagnetic waves, which consist of an electric field and a magnetic field. The electric field is responsible for carrying the signal, while the magnetic field helps to propagate it.
Now, let's evaluate each of the given options:
Option A: The claim is correct because any fabric would block the signal from the antenna as long as the antenna is completely inside it.
This option is incorrect. Fabric, especially regular fabric without any metal properties, would not block the signal from the antenna. Electromagnetic waves can pass through non-conductive materials like fabric without significant obstruction.
Option B: The claim is correct because the field cannot pass through the fabric since all charge resides on the outside of a conductor.
This option accurately describes the concept of a conductor. In the case of metalized fabric, the metal coating acts as a conductor. In a conductor, such as the metalized fabric, charges accumulate on the surface due to the redistribution of the electric field. Therefore, the electric field cannot easily penetrate the fabric, making this option a potential correct answer.
Option C: The claim is incorrect because the fabric is not solid and cannot fully block the signal.
This option is another accurate assessment. If the fabric is not solid or has holes, the signal can bypass the fabric and reach the phone. Partial blockage or lack of coverage could reduce signal strength, but it wouldn't fully protect one's privacy.
Option D: The claim is incorrect because the fabric actually helps the field get to the phone, since a conductor will focus the signal.
This option is incorrect. While it is true that conductors can influence the propagation of a signal, suggesting that the fabric would focus the signal is misleading. Conductors do not focus signals; they redistribute charges on their surfaces.
Option E: It depends on what type of metal is used. A copper pouch would work, but an aluminum one would not.
This option contains some truth. Different metals have different electrical conductivity properties. Copper is an excellent conductor, while aluminum is not as efficient. Therefore, a copper pouch would likely provide more protection than an aluminum one, which might still allow some signals to pass through.
Based on the explanations provided, the most accurate assessment among the given options is:
B: The claim is correct because the field cannot pass through the fabric since all charge resides on the outside of a conductor.
Though it should be noted that the effectiveness of a metalized fabric pouch in protecting cell phone user's privacy would also depend on factors such as the design, coverage, and quality of the material used.