Most of us may have witnessed rainbow after rainfall. We know that there are seven colours in it - VIBGYOR, Violet, Indigo, Blue, Green, Yellow, Orange, Red. The origin of these seven rainbow colors is the seven colours components in sun rays. The Rigvedic Verses states the similar fact.
RigVeda 1.50.8
सप्त त्वा हरितो रथे वहन्ति देव सूर्य I
शोचिष्केशं विचक्षण II
सप्तवर्णी रश्मियों जैसे अश्वों से नियोजित रथ में सुशोभित है सर्वद्रष्टा सूर्य! तेजस्वी रश्मियों से युक्त तू दिव्यता को धारण हैI
It states that the seven horses tied by the snakes to the chariot of God Surya(Sun) represents the seven colors of the sunlight. We know that sun rays are electromagnetic rays which traverses in the form of waves. The 'snakes' with which seven horses are tied to the chariot represents the wave like propagation of sun rays. These seven horses are named as Gayatri, Brihati, Ushnith, Jagati, Trishtubha, Anushtubha, Pankti.
RigVeda 8.72.16
अधुक्षत् पिप्युषीमिमूर्जं सप्तमदीमरि∶ सूर्यस्थ सप्त रश्मिभि∶।
वायु ने सूर्य की सात किरणों से पुष्ट हुए अन्न था रस का दोहन सात पद वाली वाणी के संयोग से कियाI
It states that the seven different colors of sun rays are of different energies. Same we have learnt in Modern Science that seven color components of sun rays are of different frequencies and thus different energies.