Correct Answer - Option 4 : X - rays
When highly energetic electrons are made to strike against metal target, electromagnetic radiations comes out. A large part of this radiation has wavelength of the order of 0.1 nm and is known as X - ray. These rays named X - ray as at that time its nature and properties were not known.
Properties of X - Ray
X - rays travel in straight line in vacuum at a speed equal to that of light (3 × 108)
X - rays are diffracted by crystals in accordance with Bragg’s law
X - rays are not deflected by electric or magnetic field as it contains no charged particles
X - rays affect a photographic plate more strongly than visible light.
When passed through a gas, X - rays ionize the molecules of the gas
