Which of the following characteristics of electrons determines the current in a conductor?

1. Drift velocity alone.
2. Thermal velocity alone.
3. Both drift velocity and thermal velocity.
4. Neither drift nor thermal velocity.

(a) Hint: The electrons do random motion due to their thermal energy.

Step 1:

The relationship between current and drift speed is given by:

I=neAvd

Here, I is current and vd is the drift velocity.

Step 2: 

So Ivd

Thus, only drift velocity determines the current in a conductor.