Check correctness of relation by dimensional analysis lambda =h/mv where letter have heir own usual meaning?
λ = h/mv [de-Broglie wavelength]
From E = hv [Plank's equation]
h = E/v
Write the dimension of each quantity in the above relation
λ = wavelength = [L] ,
h = Energy / frequency = Energy x time = [ML2 T-2 ][T] = [ML2 T-1 ]
mv = mass x velocity = momentum = [MLT-1 ]
LHS = [L]
RHS = [ML2 T-1 ] / [MLT-1 ] = [L]
We see that dimensions of both sides are equal to [L]
The given relation is correct.