# What on earth I am talking about?

When they told me to move away, I told I have no charge left .

When they told me to curl around them, I told them to increase the intensity in the field .

When I told him to curl, he was big zero .

But when he moved away, A spark was created ...

How are the two? What they are doing?

hint - The above 4 lines changed the world ..

• sounds like electromagnetic induction. – Amit Naidu Mar 10 '18 at 5:57

The two might be

electricity ("he" in the story) and magnetism ("I")

When they told me to move away, I told I have no charge left.

Similar electric charges repel each other.

On the other hand, magnetic charges (also known as magnetic monopoles) do not exist. $\nabla \cdot \mathbf {B} =0$

When they told me to curl around them, I told them to increase the intensity in the field.

a changing electric field creates a magnetic field around it. The stronger the change (increase), the greater the curl ($\nabla \times$) of the magnetic field: $\nabla \times \mathbf {B} =\mu _{0}\left(\mathbf {J} +\varepsilon _{0}{\frac {\partial \mathbf {E} }{\partial t}}\right)$

When I told him to curl, he was big zero.

An electric field has no loopiness (curl is zero) unless there is a changing magnetic field, that is $\nabla \times \mathbf {E} =-{\frac {\partial \mathbf {B} }{\partial t}}$,

But when he moved away, A spark was created ...

An electric spark is made of electric charge (electrons) jumping an air gap. However, this might be a reference to photons (electromagnetic radiation), whose speed (c) can handily be deduced from these equations, given the proper constants that can me obtained experimentally.

How are the two? What they are doing?

The two are intertwined, and they are demonstrating

Or alternatively, they might be enacting some other physics experiment, where the curling is physical more than mathematical.

• I agree, this must be it. Perhaps the fourth line relates to the fourth unused equation? – hexomino Mar 10 '18 at 11:24
• I thought of that, but fitting charge density in there would have taken some serious shoehorning.. – Bass Mar 10 '18 at 11:26
• Or, if you 'curl' a magnet (C shaped) gives a 0... – Duncan Whyte Mar 10 '18 at 12:13
• Whatever the actual reason, the stated reason for the bounty is "This question has not received enough attention", with which I whole-heartedly concur. 185 views is way too little for this puzzle. – Bass Mar 12 '18 at 12:01
• @James i mostly add bounty to all my questions .. – Amruth A Mar 15 '18 at 8:35

The electromagnetic wave? Or Induction?

• Please give some explanation as to why you think it is one of the two possible answers you've given. Otherwise this is effectively similar to randomly guessing, as far as readers are concerned. – Bilkokuya Mar 12 '18 at 11:47

I think you're referring to:

Nuclear fission triggered by a neutron against the nucleus of an atom

When they told me to move away, I told I have no charge left.

Fission is triggered by a neutron, which has no charge.

When they told me to curl around them, I told them to increase the intensity in the field.

Fission occurs with the nucleus of an atom, which is positively charged. The nucleus is the heaviest part of an atom, so needs an increased electrical field to deflect it (think alpha particles).

When I told him to curl, he was big zero.

However, a neutron itself has no charge, so it cannot be deflected.

But when he moved away, A spark was created...

Splitting an atom's nucleus releases a tremendous amount of energy, that which powers nuclear power and fission nuclear weapons.

Coming to the provided hint:

The above 4 lines changed the world ..

Nuclear fission changed the world, particularly when used during World War II.