A cathode is the electrode from which a conventional current leaves a polarized electrical device. This definition can be recalled by using the mnemonic CCD for Cathode Current Departs. A conventional current describes the direction in which positive charges move. Electrons have a negative electrical charge, so the movement of electrons is opposite to that of the conventional current flow. Consequently, the mnemonic cathode current departs also means that electrons flow into the device's cathode from the external circuit.
The electrode through which conventional current flows the other way, into the device, is termed an anode.
Hi all,
I'm doing an experiment in which I am investigating the kind of effects that sulfation has on lead-acid batteries.
In order to do that, I have to build my own simple cell using lead and lead dioxide electrodes, both immersed in a solution of concentrated sulphuric acid. However, I...
Homework Statement
A positively charged particle of mass 7.2 * 10^-8kg is traveling east with speed of 85 m/s. The particle enters a 0.31 T uniform magnetic field, and 2.2 * 10^-3 secounds later leaves the field one-quarter south with speed of 85 m/s. What is the charge of the particle and...
Homework Statement
An electron in a cathode ray tube is accelerated through a potential difference of ΔV = 11 kV, then passes through the d = 4 cm wide region of uniform magnetic field. What field strength (in mT) will deflect the electron by 10(degrees)? (Hint: is it a reasonable...
[SOLVED] Cathode Ray - No Electric Field
Homework Statement
Consider J. J. Thomson’s 2nd experiment, the discovery of the electron. Turn on a magnetic field, but turn off the electric field. If the electrons enter a region of uniform magnetic field B and length l, show that the electrons...
Can somebody please explain what actually happens in cathode ray tube? Is there any current passing through the tube? How does the anode (positive electrode) lost electrons? Is it before the effect of cathode rays? How does the cathode (negative electrode) have bigger amount of electrons? Is it...
Homework Statement
I'm have a little problem with understanding the workings of a cathode ray tube. I understand that a filament is heated and that in turn heats the cathode which, due to thermionic emission emits electrons.
OK so here is my problem. A positively charged anode is used to...
If the motion of an electron creats a magnetic field around it then why is an electron beam in a cathode ray tube deflected at right angles and not towards the magnetic field?
Also, what would be the effect of a magnetic field on a stationary (relative to the field)electron?
Homework Statement
I have to find out a relationship between the deflection of an electron beam in a cathode ray tube and the accelerating voltage.
Homework Equations
I know that theoretically D is inversely proportional to the accelerating voltage.
The Attempt at a Solution
I have to...
Is there anybody out there that can help me??
Ok in a TV set, the electrons that are emitted come from the heating filament. Now as i read on this site...the heating filament replenishes its stock of electrons from an AC supply. I understand that bit. So there is an AC supply of electrons to...
I am not sure if this is the right place to post this question but here it is any way...
Electrons leave the cathode of a TV tube at essentially zero speed and are accelerated toward the front by 10,000v potential. At what speed do they strike the screen? Express this value also as a faction...
Why is the end of the hot filament where negatively charged electrons are being fired called the cathode end. 'cat' in chemistry means positive, I assume the same goes in physics as well?
i need to find the expression for the vertical direction of a beam in a cathode ray tube, using:
Va - accelerating voltage (between cathode &anode)
Vd - deflecting voltage
ly - effective length of deflecting plates
L - distance from end of plates to the screen
d...
hi, i have an exam on wave properties in a week. and i found this on the syllabus. i can't remember learning it let alone what a cathode ray oscilloscope is (an electron gun thingymajig?) my textbooks don't explain it well. so if you know how to determine the frequency of sound using a...
The question asks to write the chemical equation representing the cathode.
The electrolyte at the cathode is Na+, Cl-, O2 and H2O
What I would do is:
Na+ + Cl- + O2 + H2O --> NaClO2 + H2O
But that's obviously wrong. Please show me how to go about it.
Thanks!
The maximum kinetic energy of photoelectrons is 3.30 eV. When the wavelength of the light is increased by 50%, the maximum energy decreases to 1.50 eV.
What is the work function of the cathode? What is the initial wavelength?
K= E_elec - deltaE
K_max = hf - E_0 = E_elec - E_0
f =...
Can someone please explain to me the difference between a cathode ray tube and a magnetron? I just started using a magnetron for sputter deposition in a project for a prof, and after reading about it, it seems to be the same. Just wondering, even though it may be a stupid question!
Thanks!
in a CRT, the deflection on the screen is 2.4 cm when the accelerating voltage is 480 V and the deflecting voltage is 36 V. what deflection on the screen will you see if the accelerating voltage is 960 V (doubled) and the deflecting voltage is 18 V (halfed)?
answer is 0.6 cm
can anyone...
After only recently learning about Cathode ray tubes at school i was taught that the striations caused in the tubes were the result of ionisation on the particles within the tube. Though this seems most correct i have also read in textbooks and been told by others a couple of other reasons for...
what is the use of AC-GND-DC switch??
wt will happen on the screen if a dry cell is connected to the CRO with AC-GND-DC button switched to AC?? then wt will happen if GND is on??
Its funny how one can forget how to do very simple things. :rolleyes:
Here is a problem I've been working on and have a mental block and can't get the darn solution. It's from Krauss's EM text
Note: Assume non-relativistic motion. I'm assuming beam enters between places with d/2 on each...
In a Cathode Ray Tube, the deflection on the screen is 2.4cm when the accelerating voltage is 480V, and the deflecting voltage is 36V. What deflection will you see on the screen if the accelerating voltage is 960V and the deflecting voltage is 18V?
How does a CRT focus an electron beam? I get the basics of it. But I'm a little confused on the details.
For electric focusing, how does accelerating the electrons cause it to focus?
I'm looking for a more mathematical treatment of the subject. Everything I've found is just descriptive...
Hey guys
In a few days i will be doing an Assessment task requiring me to do a number of things relating to experiments on Motors and Generators and Cathode Rays.. I am confident in doing all of it but the last part states we have to analyse secondary information to carry out a risk...
hi:smile:
i was approached by this problem,
prove q/m = (2V)/(B^2r^2) [2V over B-squared r-squared]
so far i have,
F[electric] = qE
F[magnetic] = Qvb
F[electric] = F[magnetic]
therefore, v = E/B
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now i am a bit confused/wrong
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E[kinetic] = (mv^2)/2...