Across a metallic conductor of non-uniform cross section a constant potential difference is applied. The quantity which remains constant along the conductor is:
drift velocity
electric field
current density
current
As we discussed in
Potential Difference -
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i.e it is clear that when an area increases the current density decreases so the number of flow of electrons will be same thus the current will be constant.
Option 1)
drift velocity
This option is incorrect.
Option 2)
electric field
This option is incorrect.
Option 3)
current density
This option is incorrect.
Option 4)
current
This option is correct.
The current depends only on the number of electrons flowing through the conductor but independent of the cross sectional area of the conductor.Hence current remains constant.