Question

You are stranded on a deserted island with 100 m of 18 gauge insulated copper wire, a light bulb rated at 3.0 V, a 50 V battery, a large iron nail, a few simple tools (including wire cutters), and your clothes. There are of course trees, rocks, sand, and other assorted island flora and fauna. (The island is a bit unique: there is a dampening field present that inhibits fire.) Since you have been stranded on the island, each night after dark a helicopter flies over.
Using the materials at hand, describe a way to get yourself rescued. (You must support your description by including brief references to any laws or equations that apply.)

Answer 1

Answer:

One can get rescued by sending SOS signals in both day and night time as explained as follows

Explanation:

To answer the question, we note that

During the day

Since the we have sand rocks and sand therefore we can inscribe SOS on the sand

We can also use the rocks to build three X marks in a trangular pattern signalling SOS

At night

1. Crete a pulsating light to attract the Helicopter

To do that we can wrap the copper wire into a coil, connect it to the 3.0 V  bulb and the 50 V battery

The current through the coil reduces and increases as the large iron nail slides in and out of the coil making the light to dim and brighten such that it is pulsating.

The equation for the current through the coil is given as follows;

$Current, \ I = \frac{Voltage}{Impedance}$

Where:

Impedance = $\bar Z$ = R +j·X

The X varies as the large nail moves in the coil.

2. SOS signal

The SOS signal can also be made directly by turning the bulb on and off using three short flashes followed by three long flashes and then three short flashes which can be effected by either completing and disconnecting the electric bulb, copper wire and 50 V battery directly as described or by covering the constantly lit bulb with the clothes sequentially.

 

Answer 2

Explanation:

Since the person has a copper wire, light the bulb and a battery. In order to show his mark during night, he would light the bulb.

For that he would be making two wires. Connect one wire with the negative end of the battery and connect the other end of wire with the base of the bulb. Connect the other wire to the positive end of the battery and to the base of the bulb. This would complete the circuit to light the bulb.

Now since battery needs to charged also, he will use the copper wire and iron nail. When he will move iron nail quickly through a coil of copper wire, electricity will be produced that would be used to charge the battery.