Photo 51 refers to an image of

Photo 51 refers to an image of

a crater on the Moon
DNA molecules
the virus responsible for COVID-19
the virus responsible for common cold
This question was previously asked in
UPSC CDS-1 – 2024
Photo 51 refers to a famous X-ray diffraction image of DNA molecules.
Photo 51 was an X-ray diffraction pattern of DNA, obtained by Rosalind Franklin and Raymond Gosling in 1952 at King’s College London. This image was crucial in determining the double helix structure of DNA by James Watson and Francis Crick.
The clarity of Photo 51 provided key information, including the helical nature of DNA, its diameter, and the spacing between the base pairs, which were essential clues for building the correct molecular model.