. A source of constant potential difference is connected across a conductor having irregular cross section as shown. Then


a. electric field intensity at P is greater than that at Q

b. rate of electrons crossing per unit area of cross-section at P is less than that at Q

c. the rate of generation of heat per unit length at P is greater than at Q

d. mean kinetic energy of free electrons at P is greater than that at Q

Best Answer

Ans: B

Sol: When a source is connected, a current starts to flow through the conductor.  Let it be I.  Then, current density at a section is equal to I/A, where A = cross-sectional area.

Since cross-sectional area at P is maximum, therefore current density at P is minimum

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