Photoelectric Effect calculation question from Dot Point (1 Viewer)

[vds700]

UV light of frequency 7 x 10¹⁵ Hz falls on a photoemitter. Photoelectrons are emitted with kinetic energy equal to 9 x 10^-19 J.

a)Calculate the work function of the emitter. I'm fine with this, just using KE = hf - W,, then rearranging. The answer is 3.74 x 10^-18 J.

b)Calculate the stopping voltage of the emitter.

c) Find the threshold frequency, I'm fine with this, the answer is 5.64 x 10¹⁵ Hz.

Also, if u increase intensity of light on a photoemitterm does this increase the voltage or current in the external circuit connecting the cathode and anode? And what effect does increasing frequency have on voltage and current in the external circuit? I'd appreciate it if someone could clarify this for me.

 

[Arowana21]

Increasing intensity of light would create photoelectrons----> from the photoelectric effect, thus would increase V and I
And from the planck's equation E=hf as frequency increases so too does the V and I and thus each photon would carry increased kinetic energy. Also this increases the total area per unit charge of photoelectrons released.

For stopping voltage, you already have the kinetic energy and the charge of electron, since electrons are the ones that are moving. ok, using the equation
E(kmax)=q times (stopping voltage), from this you can work out the V(stop) which i think is 5.625 V

 

[vds700]

Increasing intensity of light would create photoelectrons----> from the photoelectric effect, thus would increase V and I
And from the planck's equation E=hf as frequency increases so too does the V and I and thus each photon would carry increased kinetic energy. Also this increases the total area per unit charge of photoelectrons released.

For stopping voltage, you already have the kinetic energy and the charge of electron, since electrons are the ones that are moving. ok, using the equation
E(kmax)=q times (stopping voltage), from this you can work out the V(stop) which i think is 5.625 V

Thankyou, this was very helpful