Answer:

Explanation:
The resistance of a wire is given by:

where
is the resistivity of the material
L is the length of the wire
A is the cross-sectional area of the wire
1) The first wire has length L and cross-sectional area A. So, its resistance is:

2) The second wire has length twice the first one: 2L, and same thickness, A. So its resistance is

3) The third wire has length L (as the first one), but twice cross sectional area, 2A. So, its resistance is

By comparing the three expressions, we find

So, this is the ranking of the wire from most current (least resistance) to least current (most resistance).
The answer would be a positive charge
The truth is both of them are more reactive metal.
Answer: from the information given, the velocity of the water will decrease but the pipe size will remain the same.
This can be proved with bernoulli's equation.
Explanation: careful analysis of the system using bernoulli's equation of flow is shown in the image attached
Answer:
Gas like oxygen, nitrogen etc