Is it just like diffusion gradient which results in osmosis or is it something else? Moreover also when we go accroding to ohm's law current is directly propertional to potential difference, but our teacher today taught us power transmission and he said
P=VI in which if V is more then I is loss and so the energy loss, but how I has become inversely proportional to V here??

I'm having a hard time following yyour question, but I think you're asking about how Ohm's Law (V = IR) and the power equation (P=VI) work together.

The thing to keep in mind is that with Ohm's Law you can see how V and I vary for a constant load R. But for power you see how V and I vary for a constant power P, but NOT with a constant load R. If you want to keep P constant, then the only way to vary either V or I is to change the load R.

For DC circuits you can combine the two equations to express power as a function of either V or I:

P = I^2 R, or
P = V^2/R

Keeping P constant, if you double V then R must go up by a factor of 4. Then you see that I must be cut in half. Ohm's Law does indeed apply, but because you had to vary R by such a large amount to keep P constant what you find is that V and I vary inversely.

Yes, ebaines' right. Strange as it seems, that's how electricity works.

The diffusion gradient and osmosis are in biology.

Diffusion occurs along the diffusion gradient, but active transport goes against the diffusion gradient.