Answer:
true
Explanation:
An Electromagnet is called as a temporary magnet, because electromagnet is made up of insulated copper wire wrapped around soft iron, which allows current to flow in it and at that moment iron gains it magnetic properties and when the current is switched off, then there will be no flow of current and hence iron loses its magnetic properties.
Hence it works temporarily as long as electric current flows in a conductor and hence known as temporary magnet. .
If you still need the answer it is B. 2 J
The 1st one goes two added sodoes the second one then the third goes to removed then the fourth goes to added and the rest go to removed
The silver coating on the inner bottle prevents heat transfer by radiation, and the vacuum between its double wall prevents heat moving by convection. The thinness of the glass walls stops heat entering or leaving the flask by conduction.
