<u><em>Answer:</em></u>
The new current will be 18 ampere
<u><em>Explanation:</em></u>
<u>1- getting the initial resistance of the wire:</u>
<u>Based on Ohm's law:</u>
<u>We are given that:</u>
At V=10 volts, the current is 2A
<u>This means that:</u>
10 = 2*R
R₁ = 5 ohm
<u>2- getting the final resistance of the wire:</u>
<u>Resistance, resistivity and area of a wire are connected by the following rule:</u>
<u>We also know that</u> the area of the cylinder is πr²
<u>Therefore:</u>
This means that at constant resistivity and length, the resistance of the material is inversely proportional to the square of its radius
<u>In other words:</u>
At constant resistivity and length:
where R stands for resistance and r stands for radius
Now, we are given that the diameter is tripled, this means that the radius id tripled as well.
<u>Substituting in the above equation :</u>
<u>This means that:</u>
New resistance = old resistance / 9
New resistance = 5/9 ohm
<u>3- getting the final current:</u>
Again, using ohm's law, we have:
Voltage is unchanged = 10 volts
Resistance = 5/9 ohm
Therefore:
Hope this helps :)