thin walled rubber pipe filled with 0.1molar salt water (not flowing) is coiled in shape of a solenoid .
electric current of 4 amps is made to flow through water.
length of solenoid = 50 cm.
no of turns per cm length (along axis)= 10
radius of solenoid = 3 cm
will the solenoid be able to attract iron nails at distance of 10 cm from one end?
Attract? Yes.... Lift? Probably not, depends on the nails.
Use Faraday/Lenz Law to calculate the field without a core (as described). Current, area, turns, what conductor is used is not part of the equation. Put a core in the coil and the field multiplies greatly. Use mu-metal and you get orders of magnitude more than soft iron which gets orders of magnitude more than no core.
4 Amps... your salt water is likely to get warmer.
"Salt water" is a red herring, right? The only thing relevant to the magnetic field is the current...
Salt water is supposed to be a better conductor than fresh water.
You'll get some nice side effects.
Certainly if you're going to apply a DC current to that (don't know, you didn't specify).
The salt water will break down into its components elements.
Components Elements typically are H, O, Cl and Na.
Take some serious precautions while conducting your experiments.
westfw:
"Salt water" is a red herring, right? The only thing relevant to the magnetic field is the current...
magnetic relative permeability of water is comparable to that of copper
water =0.999992
copper =0.999994
and high specific heat of water keeps temperature low , hence impedance does not get too high due to high currrent
GoForSmoke:
Put a core in the coil and the field multiplies greatly. Use mu-metal and you get orders of magnitude more than soft iron which gets orders of magnitude more than no core.
i ordered some sheets of mu-metal for the core
http://custommagneticshielding.magneticshield.com/viewitems/mumetal-sheet-and-foil/mumetal-foil
GoForSmoke:
Use Faraday/Lenz Law to calculate the field without a core (as described). Current, area, turns, what conductor is used is not part of the equation.
you really meant Biot Savarts Law ,not Faraday/Lenz Law for induction?
SumitAich:
you really meant Biot Savarts Law ,not Faraday/Lenz Law for induction?
Alright then, I didn't go to school for this except HS physics. Change the field, get current / make current, change the field.
Last time I did the numbers it was in a lesson about Faraday/Lenz. Current, Area, Turns, who makes a coil to pick up nails and only uses 10 turns? Inductors with 10 I see but not electromagnets.
Whatever the name is, you seem to know that and more so my question is why the OP?
A water-coil should work only bigger than an equivalent wire coil and not likely to last as long.
Instead of a rubber tube, see if you can get a 3D printed tube. If you don't have mu-metal then heat a steel bolt till it glows and let it cool slowly. Then see if it can pick up loose staples at 100mm.
You don't even have to build the thing to see what the nail will do, just a coil that will make the same field.
Salt water" is a red herring, right? The only thing relevant to the magnetic field is the current...
magnetic relative permeability of water is comparable to that of copper
Still doesn't matter? Permeability of the core shows up in most of the solenoid equations, but not permeability of the conductors. (not the dimensions of the conductors, either.)
Context for the question would be good. It looks like a "trick question" whose answer is "yes" - "it's a solenoid with current, so it attracts the iron nails" - how strongly is a separate question.
(I did once have an exam question about the capacitance of some plates with a non-constant dieletric. Grr...)