The properties of `x` -rays as put forwarded by Rontgen in his pioneering paper on the topic are as follos:
`X`-rays posses a very strong pentrative power it can penetrate wood upto `3cm` and and aluminium foil upto `15mm` . If the hand if the hand is held between the discharge tube and the screen the dark shadow of the of the bones os visible within the slightly dark shadow of the hand"
photographc plates and film "show themselves susceptible to `x`- rays " Hence , photography provided a valuable method of studying the effect of `x`-rays
`x`rays neither reflected nor reflected refracted (so far as Rontgen could discover ). Hence , " `X` - rays as cannot be concerted by lenses"
`X`- rays discharge electrified bodies , whether the electrification is positive or negative .
`X`-rays are generated when the cathode rays of the discharge tube strike any solid body .A heavier element , such as plantium , however is much more efficient as a generator of `X` - rays than a lighter element , such as aluminium . Most of Rontgen 's observation stood the test of time, though some of them needed to be modified later. ,brgt Now today we know if electron are accelerated through a potential difference `V`, then maximum energy of emitted photon could be `E_(max)=eV, (hc)/(lambda_(min))=(hc)/(eV)`
`lambda_(min)` is also called cut off wavelength . since electron may loose very small energy in a given collision, the upper value of lambd eill approach infinity . when `X`-rays is produced in `X`-ray tube , two types of `X`-rays spectra and line are observed: continous spectra and line spectra. A continous spectra is produced by bremsstrahlung, the electromagnetic radiation produced when free electron are accelerated during collision with ions.
A line spectrum result when an electra having sufficient energy collides with a heavy atom, and an electr in an inner energy level is ejected from the atom . An electra from an outer energy level then fills the vacant inner energy level, resulting in emission of an `X`-ray photon.
The electron knocks out an inner shell electron of the atom with which it collides . Let us take an hypothetical case of a target atom whose K- shell electron has been knocked out as shown. this will create a vacancy in K-shell . sensing this vacancy an electron from a higher energy state may make a trasition to thsi vacant state. when such a transition take placce the differece of energy is converted into photon of electromagnetic radiation, which is called charactertistic `X`-rays . Now depending upon the shell from which an electron make a trasition to `K` -shell we may have different lines in the `K` series of `X`rays e.g. if electron from L shell jumps to `K` shell we have K_(alpha), if electron from M shell jumps to `K` shell we have `K_(beta)` `X` -rays and so . on . Monseley conducted many experiment on characteristic `X`-rays , the finding of whcih played an inportant role in . developing the concept opf atomic number . Moseley's observation can be expressed as `sqrtv=a(Z-b)`
where a and b are constants. Z is the atomic number of target atom n is the frequency .
`X`-rays of high penetratrating power are called hard `X`-ray. Hard `X`-rays have energy of the order of `10^(5)eV`. the minimum potential differece through ehich the electron should be accelerated in an `X`-ray tube to obtain `X`-ray of energy `10^(5)eV` is:

Options

A. `10^(5)eV`
B. `50kV`
C. `50keV`
D. `10^(5)V`

Answer

D

Explanation

If electron are accelerated through a potential difference `V,` the maximum energy energy of emitted photon could be
` E_(max)=eV.i.e 10^(5)eV=eV,V=10^(5)V`.