1.) How much would you have to raise the temperature of a copper wire (originall

Question

1.) How much would you have to raise the temperature of a copper wire (originally at 20 ?C) to increase its resistance by 18% ?

2.) Estimate how much energy is required to transmit one action potential along the axon 10

cm long of radius 30?m . The thickness of the membrane is about 10?8and the dielectric constant is about 3. [Hint: the energy to transmit one pulse is equivalent to the energy stored by charging the axon capacitance]. ANSWER IN J

3.) What minimum average power is required for

104 neurons each transmitting 150 pulses per second?

Explanation / Answer

1. Use this formula:

rho=rho_0(1+?(dT))
where "rho" is the resistivity of the material, rho_0 is the resistivity at some initial temperature, ? is the resistive temperature coefficient (some constant), and dT is delta T, the change in temperature.
Since R = rho*l/A, rho is directly proportional to R, the resistance, so if R needs to be increased 18%, rho also needs to be increased 18%. therefore:
rho=1.18rho_0
Plug that into the first formula and simplify:
0.18 = ?dT
From outside sources, I know that ? for copper is 4.3E-3, so I can solve for dT
dT = 41.86 degrees C

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.