Question

Antoine Henri Becquerel was awarded the Nobel prize in $1903$ for:
A. Discovering spontaneous radioactivity
B. Diffraction of x-rays
C. Demonstrating the influence of the earth’s magnetic field on its atmosphere
D. Investigating the absorption of light by crystals

Answer 1

The French chemist, physicist, Nobel laureate and the first person to find proof of radioactivity was Antoine Henri Becquerel.
He won the $1903$ Nobel Prize in Physics for his work in this field, along with Marie Skłodowska-Curie (Marie Curie) and Pierre Curie. Becquerel (Bq), the SI unit for radioactivity, is named after him.

Complete answer:
He became the third in his family to hold the physics chair at the Muséum National d'Histoire Naturelle in $1892$ during Becquerel's early career. Becquerel later became chief engineer of the Department of Bridges and Highways in $1894$, before he began his early experiments. The earliest works by Becquerel based on the topic of his doctoral thesis: the polarisation of light in the plane, with the phosphorescence phenomenon and the absorption of light by crystals.

A prominent case of serendipity, of how luck favours the trained mind, is the observation of spontaneous radioactivity by Becquerel. For a long time, Becquerel was interested in phosphorescence, the light emission of one colour following the exposure of a body to light of another hue. Following Wilhelm Conrad Röntgen's observation of X-rays on $5$ January, there was a surge of optimism in early $1896$.

So, the correct answer is “Option A”.

Note:
Becquerel became part of the Académie des Sciences in $1889$. Becquerel received the Rumford Award in $1900$ for his discovery of uranium radioactivity and he became an Officer of the Legion of Honour. He was awarded the Helmholtz Prize by the Berlin-Brandenburg Academy of Sciences and Humanities in $1901$. In $1903$, Henri shared with Pierre Curie and Marie Curie the Nobel Prize in Physics for the discovery of spontaneous radioactivity.