While I was thinking of installing more RAM in my laptop I read that my processor (Intel i3 4010U) supports maximum of 16gb memory whereas the motherboard of my laptop supports just 8gb of ram. So out of curiosity I tried to search whether the graphics card that can be installed also depends on the processor or motherboard ? But I could find just few ambiguous answers on websites I don't trust.
The amount of RAM your CPU supports is dependant on how your motherboard is designed.
Almost all CPUs support two channels of RAM, with each channel supporting two memory modules. The CPU also only supports memory modules of a certain size for each DIMM.
The problem with laptops is that manufacturers often only fit a single DIMM slot per channel. This effectively halves the amount of memory supported by the CPU.
What your graphics card supports depends on whether you have an integrated (built in to the CPU) graphics or dedicated graphics chip.
Integrated graphics uses the CPU memory to perform tasks and so it is limited by the same limits as your CPU. If you have dedicated graphics card then it will have it's own dedicated memory and will not be limited by motherboard memory.