Advertisements
Advertisements
Question
A wire of resistance 3 ohm and length 10 cm is stretched to length 30 cm. Assuming that it has a uniform cross section, what will be its new resistance?
Advertisements
Solution
Because three times the original length of the wire 10 cm is stretched to 30 cm
∴ Resistance becomes 9 times its resistance, i.e. 3 × 9 = 27 Ω
`"R"_1 = ρ 30/(a/3)`
= `9 [ρ 10/a]` ...(i)
`"R"_2 = ρ 10/a` put in (i)
R1 = 9R
= 9 × 3
= 27 Ω
∴ R = 3 Ω
APPEARS IN
RELATED QUESTIONS
Find the resistance of a conductor if 0.24 A current is passing through it and a potential difference of 24 V is applied across it.
Will current flow more easily through a thick wire or a thin wire of the same material, when connected to the same source? Why?
What is an Ohmic resistor?
What is Resistivity?
Four resistances of 16 ohms each are connected in parallel. Four such combinations are connected in series. What is the total resistance?
Which of the following is an ohmic resistance?
Tick(✓) the correct choice in the following:
Ohm's law is applicable to
A wire connected to a power supply of 230 V has power dissipation P1. Suppose the wire is cut into two equal pieces and connected parallel to the same power supply. In this case, power dissipation is P2. The ratio of `"P"_2/"P"_1` is
Which of the following is correct for V-I graph of a good conductor?
A current of 2amp flowing through a conductor produced 80 joule of heat in 10 sec. The resistance of the conductor is:-
