Which statement about electric and magnetic fields is true.
1)electric and magnetic fields start at a positive and end at a negative.
2)magnetic fields must start at the north pole of a magnet and end at the south pole of the magnet.
3) electric fields must leave a positive charge and end on a negative charge.
4) electric fields and magnetic fields loop from north to south

Magnetic fields must start at the north pole of a magnet and end at the south pole of the magnet.

Explanation:

The lines that shows the direction of electric and magnetic field are called electric and magnetic field lines.The direction of electric field is from positive charge to negative charge.

The magnetic filed lines start at the north pole of a magnet and end at the south pole of the magnet.

Hence, the correct option is (2) "Magnetic fields must start at the north pole of a magnet and end at the south pole of the magnet".                                                        

given:

mass of na = 115 g

excess cl2

to determine:

mass of nacl produced

explanation:

given reaction is-

2na(s) + cl2(g) → 2nacl(s)

since cl2 is in excess, na will be the limiting reagent

as per the reaction stoichiometry na: nacl = 1: 1

i.e. moles of na reacted = moles of nacl formed

now, # moles of na = mass of na/atomic mass

                                  = 115 g/23 g.mol-1 = 5 moles

therefore, moles of nacl = 5

molar mass of nacl = 58 g/mol

mass of nacl = 5 moles * 58 g.mol-1 = 290 g

ans: amount of nacl produced = 290 g

the answer is c i believe