Question

along wire is connected to the terminals of a battery. in 9.0 s, 9.6×10^20 electrons pass a cross - section along the wire. the electrons flow from left to right. part a determine the current in the wire. express your answer with the appropriate units. part b what is the direction of the electric current? from left to right from right to left

Explanation:

Step1: Recall current - charge relationship

The current $I$ is defined as the rate of flow of charge, $I=\frac{Q}{t}$. The charge of one electron is $e = 1.6\times10^{- 19}\ C$. First, find the total charge $Q$ of the electrons that pass through the cross - section.

Step2: Calculate total charge

The number of electrons $n = 9.6\times10^{20}$, and the total charge $Q=ne$. So $Q=(9.6\times10^{20})\times(1.6\times10^{-19}\ C)=153.6\ C$.

Step3: Calculate current

The time $t = 9.0\ s$. Using the formula $I=\frac{Q}{t}$, we substitute $Q = 153.6\ C$ and $t = 9.0\ s$ into it. So $I=\frac{153.6\ C}{9.0\ s}\approx17.07\ A$.

For part B, the direction of electric current is opposite to the direction of electron flow. Since electrons flow from left to right, the direction of the electric current is from right to left.

Answer:

Part A:
$I = 17.07\ A$
Part B: from right to left