Isn't the voltage reading in this image wrong?

The conductor is moved from top to bottom through the B-field. Shouldn't the reading be negative on the volt-meter?

Right-hand-rule gives that the positive charges experience a force towards us. Then the positive charges must accumulate at the terminal closest to the letter "V" in the image and the other terminal would then have negative charge. Then, if voltage is measured with the negative probe on the positive terminal of the motor the reading should be negative, right?

Source.

The right-hand rule actually uses conventional current, not electron current.

It's a lot clearer if you look at the the Lorentz Force equation that the rule comes from:

$$\F = q \vec{E} + q\vec{v} \times \vec{B}\$$

If you look closely at the $$\q\vec{v}\$$ term, you will notice that it actually dictates you point in the direction of the movement of the charge. However, the electron charge q is negative which ends up reversing the direction. Super confusing. I know.

But in this way, it can also be applied to positive charges that are moving like protons.

So if you follow this, a force is exerted on the electrons into the page which means that the right terminal of the voltmeter will be more negative than the left terminal.

Personally, the image of the voltmeter is so blurry I have no idea what anything on it is. Presumably, the left side of the dial is negative, the right side of the dial is positive with 0V being the center.

It would appear that the left terminal is the positive terminal and the right terminal is the negative terminal of the voltmeter (which is pretty common).

So it looks like it all checks out to me.

• Sorry, don't understand that. I thought the $$F_m=qu \times B$$ is defined as the force on the positive charge. And positive charges move the same way as current. Commented Mar 10, 2021 at 6:33
• @Clone No, it is the force on whatever charge is moving through the magnetic field. If it's positive charges that are moving, the force is exerted on the positive charge, but if it is negative charges that are moving, the force is exerted on negative charges and in this case, it is negative charges that are moving. And that makes q<0 which changes the direction of the cross product result. Commented Mar 10, 2021 at 6:34
• Also, can you make the photo of the voltmeter more clear. I can't tell what terminals are what. Commented Mar 10, 2021 at 6:37
• I have edited the post and provided the source to the image, which is a youtube video. Commented Mar 10, 2021 at 6:38