Question

Questions: When a thunderstorm is approaching, sailors at sea sometimes observe a phenomenon called “St. Elmo’s fire,” a bluish flickering light at the tips of masts. What causes this? Why does it occur at the tips of masts? Why is the effect most pronounced when the masts are wet? (Hint: Seawater is a good conductor of electricity.)

Short answer

Answer

The high electric potential charge of ship causes phenomenon “St. Elmo’s fire”. The tip is long and sharp so phenomenon “St. Elmo’s fire” occur at tip. The molecules of air will ionize that’s why the effect most pronounced when the masts are wet.

Step-by-step solution

Definition of electric potential  

The term electric potential is defined as the amount of work done by the unit charge in moving from one point to another against electric field.

The electric field obtained by the relation:

$\overrightarrow{E}=-\overrightarrow{\nabla }V$

Taking integration on side and taking limit from

$$\begin{gathered} {\int }_A^{B}dV=-\int Edr \\ {V}_B-V_A=-\int 0dr+C \\ {V}_B-V_A=C \\ {V}_B-V_A=C \end{gathered}$$

Explain the reason of questions

Sea water is good conductor of electricity because sea water has many types of salt. The high electric potential charge of ship causes phenomenon “St. Elmo’s fire”. The tip is long and sharp so phenomenon “St. Elmo’s fire” occur at tip. The molecules of air will ionize that’s why the effect most pronounced when the masts are wet.

Hence, the high electric potential charge of ship causes phenomenon “St. Elmo’s fire”. The tip is long and sharp so phenomenon “St. Elmo’s fire” occur at tip. The molecules of air will ionize that’s why the effect most pronounced when the masts are wet