Question Video: Relative Charge of Subatomic Particles | Nagwa Question Video: Relative Charge of Subatomic Particles | Nagwa

# Question Video: Relative Charge of Subatomic Particles Physics

Which of the following particles have a relative charge with a magnitude of 1/3? [A] Proton [B] Bottom antiquark [C] Top antiquark [D] Bottom quark [E] Down quark [F] Up antiquark [G] Strange antiquark

02:38

### Video Transcript

Which of the following particles have a relative charge with a magnitude of one-third? Proton, bottom antiquark, top antiquark, bottom quark, down quark, up antiquark, strange antiquark.

All right, so we’re looking for all the particles in this given list with a charge magnitude of one-third. We can see that this is a fractional charge. And that is the hallmark of a quark or an antiquark. Looking at our list, we see all of the choices fall under this description except one. The proton, the first item listed, has a relative charge of positive one. Right away then, we see that we can cross off this answer choice.

So now, let’s look at the quark and antiquark types listed. As we do, one important thing to keep in mind is that we’re looking for particles that have a relative charge magnitude of one-third. This means that any particle with a charge of plus or minus one-third fits this description. To get started answering this question, let’s recall the six types of quark. By pairs, there are the up and down quark, the charm and strange quark, and the top and bottom quark. When they’re written out like this, we know that all the quark types in our top row have the same relative charge, positive two-thirds. And likewise, all the types of quark in our bottom row have the same relative charge, negative one-third.

Recalling that we’re looking for particles that have a charge magnitude of one-third, we can see that the magnitude of this relative charge, negative one-third, is positive one-third. And therefore, any down, strange, or bottom quarks we see on our list qualify. Looking once more at our answer options, we see the bottom quark and the down quark listed here. And so, we know those are particles that do have a relative charge with a magnitude of one-third. And now, let’s look at the remaining particles, which are all antiquarks.

Just like with the quark types, we can write out the antiquark types according to their pairs. And now, the types in the top row have a relative charge of negative two-thirds and those in the bottom have a relative charge of positive one-third. This means that if we find the down antiquark, the strange antiquark, or the bottom antiquark in our list, then those satisfy the condition we’re looking for. And indeed, we see the bottom antiquark here and the strange antiquark here. The other two choices, the top and the up antiquark, do not have the relative charge we want. So, we can cross out those options and then select as part of our answer the bottom and strange antiquarks. So, of the particles in our original list, the bottom antiquark, the bottom quark, the down quark, and the strange antiquark, all have a relative charge with a magnitude of one-third.

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