The sun's rays hardly penetrated into the depth of the forest.
A ray of light penetrated the darkness in her heart.
It was only three o'clock but no ray penetrated to the shrouded street.
A moment later it opened, and a ray of light penetrated the darkness.
Although the sun was by now well into the sky, its rays had not yet penetrated the mist.
There is an area in the park where not even a single sun's ray can penetrate.
In the daytime they admit a fine light, and at night not even the moon's rays can penetrate.
And you also seem to be thinking: "the ray with more energy will penetrate farther".
These rays go right through window glass and can penetrate deeply into the skin.
The sun's rays penetrate the water, so protection is needed when snorkeling also.