Answer:
18.6012339739 A
Explanation:
= Vacuum permeability = 
L = Length of wire = 55 cm
N = Number of turns = 4000
I = Current
Magnetic field is given by

The current necessary to produce this field is 18.6012339739 A
Answer:
It is important because it carries useful energy through your house that you can use for a variety of tasks.
Explanation:
Hope this helped !
Explanation:
The general equation of an AC current is given by :

Where
I₀ is the peak value of current
is angular frequency

So,

We know that,

So, the frequency is 50 Hz and the maximum rms value of current is 14.14 A.
Answer: 
Explanation:
Given
Mass of water is 
mass of ice is 
Latent heat of fusion 
The heat capacity of water is 
Suppose water is at
and it reaches to
to melt the ice
the heat released by water must be equivalent to heat absorbed by the ice

Explanation:
According to Dalton's atomic theory, all the atoms are individual, all the atoms of the same element are identical in properties and mass, the compound is formed from two or more kinds of the atoms, all the matter is made up of small atoms and the chemical reaction is a rearrangement of the atoms.
The discoveries which contradicts the components of Dalton's atomic theory from the given discoveries are:
Nuclear reactions can change an atom of one element into an atom of another element.
Atoms of a given element can have different numbers of neutrons.
Atoms contain smaller particles: protons, neutrons, and electrons.