alphajm
contestada

In the late 1890s, what objection might have been raised about Becquerel’s claim that the uranium salt crystals had emitted something that exposed the photographic film?
There was no apparent source for the uranium salts’ energy.

Film only becomes exposed in response to light.

Both the crystals and the film had been exposed to sunlight during the experiment.

The crystals began to phosphoresce in the drawer and release X-rays.