1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Readme [11.4K]
3 years ago
12

A 1.70 m cylindrical rod of diameter 0.550 cm is connected to a power supply that maintains a constant potential difference of 1

4.0 V across its ends, while an ammeter measures the current through it. You observe that at room temperature (20.0 degrees C) the ammeter reads 18.5 A, while at 92.0 degrees C it reads 17.2 A. You can ignore any thermal expansion of the rod.
Find the resistivity and for the material of the rod at 20 degrees C.

Find the temperature coefficient of resistivity at 20 degrees C for the material of the rod.
Physics
1 answer:
Nikitich [7]3 years ago
4 0
Resistance = ρ * (L/A) and Rf = Ri * ([1 + α * (Tf – Ti)] 
ρ = Resistivity L = length in meters A = cross sectional area in m^2 α = temperature coefficient of resistivity 
L = 1.50 m Area = π * r^2 r = d/2 = 0.25 cm = 2.5 * 10^-3 m Area = π * (2.5 * 10^-3)^2 

The cylindrical rod is similar to a resistor. Since the current is decreasing, the resistance must be increasing. This means the resistance is increasing as the temperature increases. Resistance = Voltage ÷ Current At 20˚, R = 15 ÷ 18.5 At 92˚, R = 15 ÷ 17.2 

Now you know the resistance at the two temperatures. Let’s determine the resistivity at the two temperatures. Resistance = ρ * (L/A) ρ = Resistance * (A/L) 
At 20˚, ρ = (15 ÷ 18.5) * [π * (2.5 * 10^-3)^2] ÷ 1.5 = At 92˚, ρ = (15 ÷ 17.2) * [π * (2.5 * 10^-3)^2] ÷ 1.5 = 
Now you know the resistivity at the two temperatures. Let’s determine the temperature coefficient of resistivity for the material of the rod. 
Rf = Ri * ([1 + α * (Tf – Ti)] Rf = 15 ÷ 17.2, Ri = 15 ÷ 18.5, Tf = 92˚, Ti = 20˚ 
15 ÷ 17.2 = 15 ÷ 18.5 * [1 + α * (92 – 20)] Multiply both sides by (18.5 ÷ 15) (18.5 ÷ 15) * (15 ÷ 17.2) = 1 + α * 72 Subtract 1 from both sides (18.5 ÷ 15) * (15 ÷ 17.2) – 1 = α * 72 Divide both sides by 72 α = 1.05 * 10^-3 
You might be interested in
The escape velocity is defined to be the minimum speed with which an object of mass m must move to escape from the gravitational
s344n2d4d5 [400]

Answer:

v = √2G M_{earth} / R

Explanation:

For this problem we use energy conservation, the energy initiated is potential and kinetic and the final energy is only potential (infinite r)

        Eo = K + U = ½ m1 v² - G m1 m2 / r1

        Ef = - G m1 m2 / r2

When the body is at a distance R> Re, for the furthest point (r2) let's call it Rinf

       Eo = Ef

       ½ m1v² - G m1 M_{earth} / R = - G m1 M_{earth} / R

      v² = 2G M_{earth} (1 / R - 1 / Rinf)

If we do Rinf = infinity     1 / Rinf = 0

       v = √2G M_{earth} / R

      Ef = = - G m1 m2 / R

The mechanical energy is conserved  

 

      Em = -G m1  M_{earth} / R

      Em = - G m1  M_{earth} / R

     R = int        ⇒  Em = 0

6 0
2 years ago
Mike is a runner. Mike runs 200m in 25s; what is his average velocity during the run? assume that units are in m/s. (asap, will
maw [93]
Velocity is displacement/time
(Displacement is the overall change in distance)

So you’ll want to divide 200 by 25, which should give you:

8 m/s

5 0
3 years ago
2. A mixture of mercury and copper is an example of
Olin [163]

Answer:

b

Explanation:

liquid and solid

hope that helps :)

4 0
2 years ago
Read 2 more answers
PLEASE HELP ASAP!!! 49 POINTS AND BRAINLIEST FOR BEST AND FASTEST ANSWER!!! (DO NOT ANSWER IF YOU DON'T KNOW, OR I WILL REPORT Y
Colt1911 [192]

Neap tide = tide where there is the least difference between high and low water levels

Spring tide = tide where there is the greatest difference between high and low water levels

Equator = an imaginary line drawn around earth dividing it into northern and southern hemispheres

Seasons = the divisions of the year marked by specific weather patterns and daylight hours.

Hope this helps!

5 0
3 years ago
Read 2 more answers
I appreciate the help on this physics question
Sidana [21]
Not enough information
3 0
2 years ago
Other questions:
  • Which law represents the thermodynamic statement of the conservation of energy of a system
    12·1 answer
  • A soccer player is running upfeild at 10m/s and comes to a stop in 3 seconds facing in the same direction what is his accelerati
    11·1 answer
  • HELP PLEASE!<br>Can anyone help with any of these?
    12·1 answer
  • A 5.20g bullet moving at 672 m/s strikes a 700g wooden block atrest on a frictionless surface. The bullet emerges, travelingin t
    12·1 answer
  • The two blocks of masses M and 2M shown above initially travel at the same speed v but in opposite directions. They collide and
    8·1 answer
  • Will mark as brainliest if correct!!!!
    7·1 answer
  • Now, a second resistor R2 of 3.3 105 Ω is connected in parallel to the existing resistor in the circuit, and a second capacitor
    13·1 answer
  • Most sodium atoms have an atomic mass of 23, but a few have atomic
    7·1 answer
  • What is a sharp ridge separating two cirques
    12·1 answer
  • What would happen if you didn't have chemical energy in your body? Choose the best answer.
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!