is there any resisistive linaer palte available for online shoping

[kirtan.gopal]

I want to buy a linear in length variable restive plate

 

[BradtheRad]

I picture that you are talking about the plate that goes inside a potentiometer. It is covered with a substance that yields different resistance values, depending on how far apart you place two contacts.

I have never seen such a plate available by itself. I suppose you will have to disassemble a potentiometer in order to get one.

There are rheostats, made from resistive wire, and a sliding contact. This is not a plate, because the wire is in a coil.

You can obtain lengths of nichrome wire (or other resistive element), and run a sliding contact on that, to obtain different ohm values.