Consider the fundamental physics for class XII. Suppose the voltage applied to A is increased. The diffracted beam will have the maximum at a value of `theta` that

Options

A. will be larger then that earlier value
B. will be the same as the earlier value
C. will be less than the earlier value
D. will depend on the target

Answer

c

Explanation

In Davisson and Germer Experiment, if V is the voltage applied to anode, then de-Broglie wavelength associated with electron is
`lambda=12.27/(sqrt(V))Å.......(i)`
If there is a maxima of the diffracted electrons at an angle `theta`, then `2d sin theta=lambda.........(ii)`
From (ii), we note that as `lambda` decreases, the value of `sin theta` decreases, i.e., `theta` decreases.