The relationship between current, charge, and electron velocity can be confusing, but let's break it down to understand why the velocity of electrons in a wire carrying 1 ampere of current can be much lower than you might expect.
1 ampere (A) is defined as 1 coulomb (C) of charge passing through a point in a circuit per second. One coulomb is a large amount of charge, and it consists of approximately 6.25 x 10^18 elementary charges, which are electrons in this case.
When we say that 6.25 x 10^18 electrons flow through a wire per second for a current of 1 ampere, it doesn't mean that each electron is moving with a velocity of 1 mm/s. In fact, the individual electron velocity is typically quite small.
In a conductor, such as a wire, electrons are already present in the material due to thermal motion. When a voltage is applied across the wire, these free electrons drift in response to the electric field created by the applied voltage. The drift velocity of electrons is typically quite low, on the order of a few millimeters per second or even less.
However, despite the low drift velocity of individual electrons, the overall current in the wire can be high because of the large number of electrons in motion. Picture a crowded subway platform where individual people move slowly, but the flow of people collectively creates a significant current.
So, the 1 ampere of current in a wire corresponds to a large number of electrons passing through a given point each second. Although the velocity of individual electrons is relatively slow, the collective motion of a vast number of electrons results in the observed current.
In summary, the 1 ampere of current refers to the rate of charge flow, which involves a large number of electrons passing through a point in the wire. The relatively low velocity of individual electrons is compensated by the enormous number of electrons involved, allowing for a significant current to be maintained in the wire.