Problem 1: A conducting wire has a 2.0 mm diameter, a 4.0 m...

Problem 1: A conducting wire has a 2.0 mm diameter, a 4.0 m length, and a 50 m? resistance. What is the resistivity of the material ? (40 p) Problem 2 : A certain X-ray tube operates at a current of 7.0 mA and a potential difference of 80 kV. What is its power in watts ? (30 p) Problem 3 : Write down the mathematical relation between current density and electric field (namely microscopic form of the Ohm's law). (30 p)

Labs

Want to see this concept in action?

NEW

Explore this concept interactively to see how it behaves as you change inputs.

View Labs

Transcript

00:01 Hello, here we have to solve an assignment and let's start with problem number one.

00:08 Here we have to calculate the resistivity of the material and let's start with the formula for the resistance.

00:15 Resistance equals to resistivity times length divided by the surface area.

00:22 And here that is resistivity times lengths divided by pi d squared over 4, which is raw times 4l over pi.

00:33 D squared then resistivity equals to r times pi d squared divided by 4l now let's complete this calculation that equals to 50 times 10 power by negative 3 oms times pi times squared diameter which is 2 .0 times 10 power by negative 3 meters that is squared and that's divided by the length which is 4 times 4 .0 meters.

01:14 Let's complete this calculation.

01:38 That equals to 3 .93 times 10 power by negative 8 oms meter which is roughly 3 .9 times 10 power by negative 8 oom meter.

01:57 Let's answer to problem 1.

02:00 Now, let's move on and here we have to calculate potential difference.

02:05 Oh, sorry, we have to calculate the power of the x -ray tube.

02:10 Power equals to current times voltage, which is 7 .0 times 10 power by negative 3 ampers times potential difference, which is 80 times 10 power by 3 volts.

02:28 Let's calculate it.

02:37 That equals to 560 watts.

02:47 And lastly, let's calculate...

Question

Please give Ace some feedback