Current Electricity Charging Discharging Of Capacitors Question 381
Question: A steady current flows in a metallic conductor of non-uniform cross-section. The quantity/ quantities constant along the length of the conductor is/are
[KCET 1994, IIT 1997 Cancelled; CBSE PMT 2001]
Options:
A) Current, electric field and drift speed
B) Drift speed only
C) Current and drift speed
D) Current only
Show Answer
Answer:
Correct Answer: D
Solution:
If E be electric field, then current density j = $ \sigma E $ Also we know that current density $ j=\frac{i}{A} $ Hence j is different for different area of cross-sections. When j is different, then E is also different. Thus E is not constant. The drift velocity $ v _{d} $ is given by $ v _{d}=\frac{j}{ne} $ = different for different j values. Hence only current i will be constant.
BETA
