# Physics

A cylindrical copper cable 1.50Km long is connected across a 220.0V potential difference.
(a) What should be its diameter so that it produces heat at a rate of 50.0W?
(b) What is the electric field inside the cable under these conditions?

1. 👍 0
2. 👎 0
3. 👁 317
1. First, the value of the length of the cable will be converted to meters.

Therefore, the length of the cable is L = 1.5*10^3 m = 1500 m.

We know, from enunciation, the value of potential difference:V = 220 volts

The power is given and it's value is of P = 50 Watts

P = V^2/R => R = V^2/P

Since the area of the section of the cable is circular, w'ell recall the formula for the area of the circle:

A = pi*r^2 (1)

A = p*L/R (2), where p = 1.72/10^8 ohm/m

We'll equate (1) and (2) and we'll get:

pi*r^2 = p*L*P/V^2

r^2 = p*L*P/V^2*pi

r = sqrt(p*L*P/V^2*pi)

Diameter is d = 2*r = 2*sqrt(p*L*P/V^2*pi)

d = 2*sqrt1.72*10^-10*15*5*10^3/484

d = 2*sqrt 1.72*10^-7*75/22

d = 1.0325/100

d = 0.010325 meters

The diameter of the cable is of d = 0.010325 meters, such as it is producing heat at a rate of 50W.

1. 👍 0
2. 👎 0

## Similar Questions

1. ### physics

An isolated capacitor of unknown capacitance has been charged to a potential difference of 100 V. When the charged capacitor is then connected in parallel to an un- charged 10.0 μF capacitor, the potential difference across the

asked by dani on May 24, 2016
2. ### Physics

Two resistors 10 Ω and 5 Ω are connected in parallel across a 15 V battery. What is the potential difference across the 10 Ω resistor? 5 V 10 V 15 V 20 V My answer would be A; 5 V

asked by Herp on October 21, 2012
3. ### Chemistry

A zinc-copper battery is constructed as follows at 25°C. Zn|Zn^2+ (0.15 M)||Cu2+(3.00 M)|Cu The mass of each electrode is 200. g. a) Calculate the cell potential when this battery is first connected. - i got this to be 1.14V b.)

asked by Pamela on April 28, 2011
4. ### Physics

The potential difference across the terminals of a storage battery not connected in any circuit is observed to be 12 V. When it is connected to an external resistance the potential difference across the terminals is observed to be

asked by DariaV on July 29, 2019
1. ### physics (thxs again)

Thank you for the help :) A certain sample carries a current of 4A when the potential difference is 2V and a current of 10A when the potential difference is 4V. This samples is: a) obeys ohm's law b) has a resistance of 0.5 ohms

asked by susan on March 14, 2007
2. ### Physics 2

A cyllindrical copper cable carries a current of 1200 A. There is a potential difference of 1.6×10−2 V between two points on the cable that are 0.24 m apart. What is the radius of the cable?

asked by Chris on February 11, 2010
3. ### physics

A source of e.m.f 110v and frequency 60hz is connected to a resistor, an indicator and a capacitor in series. When the current in the capacitor is 2A.the potential difference across the resistor is 80v and that across the inductor

asked by Ayo on March 24, 2010
4. ### physics

Two capacitors, C1 = 5 μF and C2 = 12 μF, are connected in parallel, and the resulting combination is connected to a 9 V battery. Find (a) the equivalent capacitance of the combination, (b) the potential difference across each

asked by maram on May 13, 2019
1. ### Math

Towns A to F are to be connected by cable along existing roads. Need to figure the minimum length of cable required. Eash town must be connected to at least one other town. Distances are in miles. A-B 20, A-E 71, A-F 38, B-A 20,

asked by Cassidy on March 16, 2014
2. ### Physics

Two resistors 10 Ω and 5 Ω are connected in parallel across a 15 V battery. What is the potential difference across the 10 Ω resistor? 5 V 10 V 15 V 20 V I would think the answer would be B, or 15V

asked by Fleur on October 22, 2012
3. ### physics

1.calculate the work done on a capacitor of capacitance of 200uF, when a potential difference of 100v is applied 2.find the area of a capacitor 1pF,if the distance between the plate is 76cm(=8.85×10^-12f/m) 3.A series arrangement

asked by Maballs on October 9, 2019
4. ### physics

A 1100 wrecking ball hangs from a 10 -long cable. The ball is pulled back until the cable makes an angle of 28.0 with the vertical.By how much has the gravitational potential energy of the ball changed?

asked by Mak on January 28, 2013