What is the de Broglie wavelength associated with an electron accelerated through a potential difference of 150 Volt is?

Q: Electrons are accelerated through a potential difference of 150 V. Calculate the de-Broglie wavelength.

Sol: V = 150 V ; h = 6.62 × 10-34 Js, m = 9.1 x 10-31 kg,

e = 1.6 x 10-19 C

$\large \lambda = \frac{h}{\sqrt{2 m e V}} $

$\large \lambda = \frac{6.62 \times 10^{-34}}{\sqrt{2 \times 9.1 \times 10^{-31} \times 1.6 \times 10^{-19}\times 150}}$

= 1 A°

The following graph shown the variation of stopping potential V0 with the frequency v of the incident radiation for two photosensitive metals P and Q:

What is the de Broglie wavelength associated with an electron accelerated through a potential difference of 150 Volt is?

(i) Explain which metal has smaller threshold wavelengths.(ii) Explain, giving reason, which metal emits photoelectrons having smaller kinetic energy.

(iii) If the distance between the light source and metal P is doubled, how will the stopping potential change? 

(i) Suppose the frequency of incident radiations of metal Q and P be v0 and v0

’ respectively.
                

What is the de Broglie wavelength associated with an electron accelerated through a potential difference of 150 Volt is?

                 
What is the de Broglie wavelength associated with an electron accelerated through a potential difference of 150 Volt is?

                 
What is the de Broglie wavelength associated with an electron accelerated through a potential difference of 150 Volt is?

              
What is the de Broglie wavelength associated with an electron accelerated through a potential difference of 150 Volt is?
Therefore,  metal 'Q' has smaller wavelength.(ii) As we know,

E = hv0


What is the de Broglie wavelength associated with an electron accelerated through a potential difference of 150 Volt is?
Hence, metal 'P' has smaller kinetc energy.

(iii) Stopping potential remains unaffected because the value of stopping potential for a given metal surface does not depend on the intensity of the incident radiation. It depends on the frequency of incident radiation.

Uh-Oh! That’s all you get for now.

We would love to personalise your learning journey. Sign Up to explore more.

Sign Up or Login

Skip for now

Uh-Oh! That’s all you get for now.

We would love to personalise your learning journey. Sign Up to explore more.

Sign Up or Login

Skip for now