Which of the following rays is discovered by Wilhalm Röentgen?

SOLUTION

Option 3 is correct, i.e. X rays.

X rays:

• Wilhelm Röentgen (1845-1923) in 1895 showed that when electrons strike a material in the cathode ray tubes, produce rays which can cause fluorescence in the fluorescent materials placed outside the cathode ray tubes. Since Röentgen did not know the nature of the radiation, he named them X-rays and the name is still carried on.
• It was noticed that X-rays are produced effectively when electrons strike the dense metal anode, called targets. These are not deflected by the electric and magnetic fields and have a very high penetrating power through the matter and that is the reason that these rays are used to study the interior of the objects.
• These rays are of very short wavelengths (∼0.1 nm) and possess electromagnetic character.

Alpha rays:

• Rutherford found that α-rays consists of high energy particles carrying two units of positive charge and four-unit of atomic mass.
• He concluded that α- particles are helium nuclei as when α- particles combined with two electrons yielded helium gas.

Note:

• Beta rays(β-rays) are negatively charged particles similar to electrons.
• Gamma rays(γ-rays) are high energy radiations like X-rays, are neutral in nature and do not consist of particles.