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91Ó°ÊÓ

What fraction of a beam of 50eVelectrons would get through a 200V1nm wide electrostatic barrier?

Short Answer

Expert verified

The required answer is 1.1×10-54

Step by step solution

01

Definition of Tunneling

Tunneling defines the penetration of a barrier of high energy by a low-energy wave or particle. For a wide barrier that transmits ineffectively:

T=16EU(1-EU)e-2kl

Where,k=2mU-Eand l is width of penetration barrier,U=qV

02

Given/known parameters

V=200V,E=50eV,I=1nm=10-9m

03

Solution

U=qv=1.6×10-19×200J1.6×10-19eV/J=200eV

k=2×9.1×10-31×(200-50)×1.6×10-19J/eV1.05×10-34

k=62.7×109m-1

Now,T=16502001-50200e-2×62.7×109×10-9=1.1×10-54

04

Explanation and Conclusion

The fraction of beam of 50eVtransmitted through a barrier of 200Vand 1nmwidth is1.1×10-54.

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