Question

One of tha combinations from the fundamental physical constants is hc/g the unit of this expression is

Answer 1

h is plank's constant ,
we know, E = hv , according to energy of photon where E is energy and v is frequency of photon. So, dimension of h = dimension of E/dimension of v
= [ML²T⁻²]/[T⁻¹] = [ML²T⁻¹]
∴ dimension of h = [ML²T⁻¹]

similarly, dimension of c = dimension of speed/velocity = [LT⁻¹]
dimension of g = dimension of acceleration = [LT⁻²] [generally g is known as acceleration due to gravity . If you write G then, it means gravitational constant. But here g , so I assume acceleration due to gravity e.g., acceleration]

Now, dimension of hc/g = [ML²T⁻¹][LT⁻¹]/[LT⁻²] = [ML²]
Hence, unit of hc/g = kgm²

Answer 2

Use dimensional formula to get answer.

Since base unit of M is Kg and for L we have m so M¹L²=Kgm²