Respuesta :
Answer:
a) Â R_c = 1.18 ohms
b the resistance of copper wire is 14.7 % of resistance of speakers.
Explanation:
Given:
- 24-Gauge copper wire resistivity p = 1.72*10^-8
- The Length of the single wire L = 7 m
- The diameter of single copper wire d = 0.51 mm
Find:
A) What is the minimum resistance of the connecting speaker wires at 20ËšC?
Part B) Compare the resistance of the wire to the resistance of the speaker (RSP = 8 Ω).
Solution:
- We are given details of as single copper wire. However, it takes two copper wire to connect a speaker to the amplifier. After establishing that fact we can use the relation between the dimensions of the wire and the resistance as follows:
                    R = p*L / A
Where,
R is the resistance of the wire in ohms
A is the cross sectional area of the wire
- Now for two wires the resistance would be twice:
                    R_c = 2*p*L / A
- plug in the values:
                    R_c = (2*1.72*10^-8 * 7 ) / (pi*(0.00051)^2 / 4)
- Evaluate:
                    R_c = 1.18 ohms
- The wire resistance calculated can be compared with that of speaker by taking a ratio of the two:
                    R_c / R_s
                    1.18 / 8  * 100 = 14.7 %
- Hence, the resistance of copper wire is 14.7 % of resistance of speakers.
