Current Electricity and Electrical InstrumentHard
Question
wire of length L is drawn such that its diameter is reduced to half of its original diameter. If the initial resistance of the wire were 10Ω its new resistance would be:
Options
A.40 Ω
B.80 Ω
C.120 Ω
D.160 Ω
Solution
Let the new length be l1, keeping volume constant,
πr2L = π
⇒ l1 = 4L
Now,
R = 60
πr2L = π
⇒ l1 = 4L
Now,
R = 60
Create a free account to view solution
View Solution FreeTopic: Current Electricity and Electrical Instrument·Practice all Current Electricity and Electrical Instrument questions
More Current Electricity and Electrical Instrument Questions
The contribution in the total current flowing through a semiconductor due to electrons and holes are and respectively. I...Assertion :- [Pt(trien)]+2 is more stable complex cation than [Pt(en)2]+2. Reason :- Trien is a chelating ligand....A battery has e.m.f. 4V and internal resistance ′r′. When this battery is connected to an external resistanc...In the following circuit, the resistance of a voltmeter is 10,000 Ω and that of an ammeter is 20 Ω . If the re...Three 60W, 120W light bulbs are connected across a 120 V power source. If resistance of each bulb does not change with c...