The famous physicist Victor Franz Hess is known for the discovery of:

Cosmic Radiation:- • These are high-energy particles that travel through space and bombard Earth's atmosphere. • They were discovered by Victor Franz Hess in 1912, when he made a series of balloon ascents to measure the ionization of the atmosphere at different altitudes. (Hence option 1 is correct). • He found that the ionization increased with altitude, even though the atmosphere becomes less dense at higher altitudes. • This led him to conclude that there must be a source of radiation coming from outside the atmosphere.