Physics, 18.03.2021 01:20 skyemichellec

Three cylindrical wires, 1, 2, and 3 are made of the same materialand have resistances R1, R2, and R3, respectively. Wires 1 and 2 have the same lengthbut diameter of wire 2 is twice that of wire 1. Wires 2 and 3 have the same diameterbut length of wire 3is twice that of wire 2. 1. Rank the wires according to their resistances, greatest first.
A. R1> R2> R3R1
B. R1> R3> R2R2
C. R2> R1> R3R3
D. R2> R3> R1
E. R3> R1> R2
F. R3> R2> R1Q2.
2. If same voltage is applied across each of the wires, which one will dissipate heat at the highest rate

Answers: 3

Show answers

Answers

Answer from: angiejtc0908

1) R₁ > R₃ > R₂ correct B , 2) the wire that dissipates the most is wire 2

Explanation:

1) The resistance of a wire is given by the expression

R = $\rho \ \frac{l}{A}$

where ρ is the resistivity of the material, l the length of the wire and A the area of the wire

The area is given by

A = π r² = π d² / 4

we substitute

R = (ρ 4 /π) $\frac{l}{d^2}$

the amount in parentheses is constant for this case

let's analyze the situation presented, to find the resistance of each wire

* indicate l₁ = l₂ and d₂ = 2 d₁

the resistance of wire 1 is

R₁ = (ρ 4 /π) $\frac{l_1}{d_1^2}$

the resistance of wire 2 is

R₂ = (ρ 4 /π) \frac{l_2}{d_2^2}

R₂ = (ρ 4 /π) $\frac{l_1}{ (2 d_1)^2}$

R₂ = (ρ 4 /π ) $\frac{l_1}{d_1^2}$ ¼

R₂ = ¼ R₁

* indicate that d₂ = d₃ and l₃ = 2 l₂

R2 = (ρ 4 /π) $\frac{l_2}{d_2^2}$

the resistance of wire 3 is substituting the indicated condition

R3 = (ρ 4 /π 2) \frac{l_3}{d_3^2}

R3 = (ρ 4 /π) $\frac{2 \ l_2}{d_2}$

R3 = 2 R₂

let's write the relations obtained

R₁ = (ρ 4 /π) $\frac{I_1}{ d_1^2}$

R₂ = ¼ R₁

R₃ = 2 R₂

let's write everything as a function of R1

R₁ =(ρ 4 /π) $\frac{l_1}{d_1^2}$

R₂ = ¼ R₁

R₃ = ½ R₁

the resistance of the wire in decreasing order is

R₁ > R₃ > R₂

2) The power dissipated by a wire is

P = V I

the voltage is

V = I R

I = V / R

substituting

P = V² / R

therefore the power dissipated by each wire is

wire 1

P₁ = V² / R₁

wire 2

P₂ = V² / R₂

P₂ = $\frac{V^2}{ \frac{1}{4} R_1}$

P₂ = 4 P₁

wire 3

P₃ = V² / R₃

P₃ = $\frac{V^2}{ \frac{1}{2} R_1}$

P₃ = 2 P₁

Therefore, the wire that dissipates the most is wire 2

Answer from: Quest

what is the speed of a softball that travels 20m in 2secs

speed = 20/2 = 10 m/s

Answer from: Quest

neither accurate nor precise.

Another question on Physics

Physics, 21.06.2019 17:30

The particles of an ice cube at 0°c (represented by the blue circles) come in contact with the particles of juan’s hand at 37°c (represented by the orange circles). which diagram correctly represents the temperature of the two substances and the direction of heat flow?

Answers: 3

Answer

Physics, 21.06.2019 22:40

Ablock of mass m = 2.5 kg is attached to a spring with spring constant k = 710 n/m. it is initially at rest on an inclined plane that is at an angle of θ = 23° with respect to the horizontal, and the coefficient of kinetic friction between the block and the plane is μk = 0.19. in the initial position, where the spring is compressed by a distance of d = 0.16 m, the mass is at its lowest position and the spring is compressed the maximum amount. take the initial gravitational energy of the block as zero. a) what is the block's initial mechanical energy? b) if the spring pushes the block up the incline, what distance, l, in meters will the block travel before coming to rest? the spring remains attached to both the block and the fixed wall throughout its motion.

Answers: 3

Answer

Physics, 22.06.2019 02:50

Steam is generated in a boiler of a cogeneration plant at 10 mpa and 450°c at a steady rate of 5 kg/s. in normal operation, steam expands in a turbine to a pressure of 0.5 mpa and is then routed to the process heater, where it supplies the process heat. steam leaves the process heater as a saturated liquid and is pumped to the boiler pressure. in this mode, no steam passes through a condenser, which operates at 20 kpa. (a) determine the power produced in the turbine and the rate at which process heat is supplied in this mode. (b) determine the power produced in the turbine and the rate of process heat supplied if only 60 percent of the steam is routed to the process heater and the remainder is expanded to the condenser pressure. (3.32 mw; 9.69 mw; 4.25 mw; 5.82 mw)

Answers: 3

Answer

Physics, 22.06.2019 05:30

What is a neurotransmitter involved in mood reward, addiction, and motor behaviors?

Answers: 3

Answer

You know the right answer?

Three cylindrical wires, 1, 2, and 3 are made of the same materialand have resistances R1, R2, and R...

Questions