A beam contains `2.0xx10^8` doubly charged positive ions per cubic centimeter, all of which are moving toward north with a speed of `1.0xx10^5 ms^(-1)`. (a) what are the magnitude and direction of the current density `vecJ`? (b) can you calculate the total current i in this ion beam? If not what additional informaiton in needed.

Explanation

To solve the problem step by step, we will address both parts of the question regarding the current density \( \vec{J} \) and the total current \( I \).

### Given Data:
- Number density of ions \( n = 2.0 \times 10^8 \) ions/cm³
- Speed of ions \( v_d = 1.0 \times 10^5 \) m/s
- Each ion is doubly charged, so the charge \( q = 2e \) where \( e = 1.6 \times 10^{-19} \) C.

### Step 1: Convert the number density from cm³ to m³
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