What is the definition of cathode in the photoelectric effect?

In summary, the terms anode and cathode are often used to refer to the positive and negative plates in a circuit, respectively. However, in the photoelectric effect, the electrons are gained at the anode and lost at the cathode of the discharge tube. This is because the flow of electrons is clockwise through the circuit, with electrons accumulating on the anode and flowing onto the left of the cathode. It is recommended to reserve the terms anode and cathode for instances where oxidation and reduction reactions occur, as it can be confusing in other contexts.
  • #1
Rongeet Banerjee
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Homework Statement
Is definition of Cathode defeated?
Relevant Equations
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We know anode=oxidation=loss of electrons and cathode=reduction=gain of electrons but in the photoelectric effect the electrons are gained at the anode and lost at the cathode of the discharge tube? References: Anode, Cathode, Oxidation, Reduction
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Electrons flow clockwise through the circuit drawn. You could say that electrons accumulated on the anode are lost to the wire on the right of the anode, and that electrons flow onto the left of the cathode so that the cathode gains electrons. That is the more natural interpretation if you think of the discharge tube as a component in a larger circuit.

But I agree, it is a little ambiguous. Which is why a better terminology would be to just refer to the "positive" and "negative" plates, and reserve the terms "anode" and "cathode" for instances where we actually have oxidation and reduction reactions occurring at the electrodes, in which case the electrochemistry is completely unambiguous.

Unfortunately, the ambiguous terminology is still quite common!
 
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1. What is the definition of cathode in the photoelectric effect?

The cathode in the photoelectric effect refers to the negatively charged electrode in a vacuum tube or photoelectric cell. It is the electrode from which electrons are emitted when light of a certain frequency is shone on it.

2. How does the cathode play a role in the photoelectric effect?

The cathode is an essential component in the photoelectric effect as it is responsible for emitting electrons when light of a certain frequency, known as the threshold frequency, is incident on it. These electrons are then collected by the anode, creating an electric current.

3. Is the cathode always negatively charged in the photoelectric effect?

Yes, the cathode is always negatively charged in the photoelectric effect. This is because in order for electrons to be emitted, the cathode must have a lower potential energy compared to the anode. This potential difference creates an electric field that accelerates the electrons towards the anode.

4. Can the cathode be made of different materials in the photoelectric effect?

Yes, the cathode can be made of different materials in the photoelectric effect. However, the material must have a low work function, meaning it requires little energy for electrons to be emitted. This is necessary for the photoelectric effect to occur.

5. Is the cathode the only electrode involved in the photoelectric effect?

No, the cathode is not the only electrode involved in the photoelectric effect. The anode, which is the positively charged electrode, is also necessary for the effect to occur. It collects the emitted electrons and completes the circuit, allowing for the measurement of the electric current produced.

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