Thank you for registering.

One of our academic counsellors will contact you within 1 working day.

Please check your email for login details.

Use Coupon: CART20 and get 20% off on all online Study Material

Total Price: Rs.

There are no items in this cart.
Continue Shopping

why only concentric rings are seen on the screen and how u conclude that these are not because of X-rays

why only concentric rings are seen on the screen and how u conclude that these are not because of X-rays


1 Answers

879 Points
10 years ago

Dear student,

About the same time as Davisson and Germer, Sir G.P. Thompson, working with his assistant A. Reid, took a thin gold foil, rolled it to be extremely flat, placed it in front of a 30 kV electron beam, and recorded the accompanying image on their photographic plate. The rings are associated with electron diffraction from the interplanar spacing within tiny crystallites in the gold foil. The continuous rings arise because the tiny crytallites are randomly oriented in the foil. Subsequently they took a sample of aluminium and did not roll it but worked carefully with it to obtain a crystalline sample. When this was exposed to their beam, spots lying around a ring-like structure were observed. This is seen in the figure below. Electrons indeed behave exactly as if they were waves.
Thompson's Aluminum Crystal Experiment

It is interesting to recall that G.P. Thompson, who shared the 1937 Nobel Prize with Davisson for these experiments which proved that electrons are waves, is the son of J.J. Thompson who received the Nobel Prize in 1906 for proving that cathode rays were actually particles - electrons! And the amazing thing is that they were both right.





Please feel free to ask your queries here. We are all IITians and here to help you in your IIT JEE preparation.

All the best.

Win exciting gifts by answering the questions on Discussion Forum. So help discuss any query on askiitians forum and become an Elite Expert League askiitian.

Now you score 5+15 POINTS by uploading your Pic and Downloading the Askiitians Toolbar  respectively : Click here to download the toolbar..


Askiitians Expert

Sagar Singh

B.Tech, IIT Delhi

Think You Can Provide A Better Answer ?

Provide a better Answer & Earn Cool Goodies See our forum point policy


Get your questions answered by the expert for free