Which of the following statements is INCORRECT?

Electric charge is a vector quantity.

The correct answer is option 4. Electric charge is a vector quantity.

Let us delve into the explanation of each statement provided:

1. Electric charge is a scalar quantity:

This statement is incorrect. Electric charge is not a scalar quantity; it is a fundamental property of matter. Scalars have only magnitude, while vectors have both magnitude and direction. Electric charge, however, does not have a direction associated with it, so it is not considered a vector quantity. Instead, it is a scalar quantity.

2. Protons are positively charged:

This statement is correct. Protons are subatomic particles found in the nucleus of atoms. They carry a positive electric charge, which is equal in magnitude to the charge of an electron but opposite in sign. Protons contribute positively to the overall charge of an atom.

3. Electrons are negatively charged:

This statement is correct. Electrons are subatomic particles that orbit the nucleus of atoms. They carry a negative electric charge, which is equal in magnitude to the charge of a proton but opposite in sign. Electrons contribute negatively to the overall charge of an atom.

4. Electric charge is a vector quantity:

This statement is incorrect. As mentioned earlier, electric charge is not a vector quantity; it is a scalar quantity. Scalars have only magnitude and no direction associated with them. Electric charge is characterized solely by its magnitude (either positive or negative) and does not have a direction component.

In summary, the incorrect statement among the options provided is that "Electric charge is a vector quantity." Electric charge is actually a scalar quantity, while protons are positively charged particles, and electrons are negatively charged particles.