@ sakshi
Frequency is besically defined as the vibrations or oscillations happening per second ,
if u would relate it to the light waves then the vibration happening in each particle of light ray are called as frequency of that particle ..
AND INTENSITY MEANS THE POWER TRANSFERRED PER UNIT AREA .
for example , suppose you are putting some frequency of light in a particular unit area , then its called as intensity when u will devide that freqency with area ,
u need to only remember that when an area is their then thats intensity .
and about the planks concept , thats simple enough ,
he did an experiment related to black body radiation .,
acc to the planks law the electromagnetic radiation emitted by a black body in thermal equilibrium at a definite temperature,,,
and this result further prooves the foundation for quantum theory ..
and the maxwell gave a set of diffrential equations , which prooves the light to be an electromagnetic waves , this leds to the foundation of electrodynamics .
KINDLY , ELABORATE YOUR QUERY . THAT WHAT CONCEPT U ARE NOT GETTING IN MAXWELL AND PLANK THEORY ,
HOPE IT CLEARS YOUR DOUBT
IF ANY MORE , THEN ASK IT ..
ALL THE BEST ..
