Single Choice

If the wavelength is brought down from $$6000 \mathring{A}$$ to $$4000 \mathring{A}$$ in a photoelectric experiment, then what will happen ?

AThe work function of the metal will increase
BThe threshold frequency will decrease
CNo change will take place
DCut off voltage will increase
Correct Answer

Solution

We know,
Stopping potential (or cut off voltage) is given by Vo=
hc
e

(
1
λ

)−
ϕ
e

where λ is the wavelength of the incident photon.
Since work function ϕ is the property of the metal surface, thus it does not depend on the wavelength of incident photon. Hence ϕ remains the same.
As per the equation,
when the wavelength of the incident photon decreases, the stopping potential will increase according to the equation.

SIMILAR QUESTIONS

Modern Physics

The threshold frequency for a photo-sensitine metal is $$3.3\times { 10 }^{ 14 }Hz$$. If light of frequency $$8.2\times { 10 }^{ 14 }Hz$$ is incident on this metal, the cut-off voltage for the photo-electric emission is nearly

Modern Physics

In the arrangement shown in figure , y=1.0mm, d=0.24mm and D= 1.2m. The work function of the material of the emitter is 2.2 eV. Find the stopping potential V needed to stop the photocurrent.

Modern Physics

The value of stopping potential for $$\lambda _2$$ in the following diagram is

Modern Physics

According to Einsteins photoelectric equation, the graph between the kinetic energy of photoelectrons ejected and the frequency of incident radiation is :

Modern Physics

The slope of graph drawn between stopping potential and frequency of incident light for a given surface will be:-

Modern Physics

The minimum frequency v of continuous X-rays is related to the applied potential difference V as?

Modern Physics

The figure showing the correct relationship between the stopping potential $$V_0$$ and the frequency $$v$$ of light for potassium and tungsten

Modern Physics

The figure shows different graph between stopping potential $$(V_0)$$ and frequency $$(v)$$ for photosensitive surface of cesium, potassium, sodium and lithium. The plots are parallel. Correct ranking of the targets according to their work function greatest first will be

Modern Physics

In a photocell circuit the stopping potential, $$v_0$$ , is a measure of the maximum kinetic energy of the photoelectrons. The following graph shows experimentally measured values of stopping potential versus frequency v of incident light. The values of Planck's constant and the work function as determined from the graph are (taking the magnitude of electronic charge to be $$ e= 1.6 \times 10^{-19} C $$ )

Modern Physics

Representing the stopping potential V along y-axis and $$(1/\lambda)$$ along x-axis for a given photocathode, the curve is a straight line, the slope of which is equal to

Contact Details