1. Can we store energy from lightening strokes in some form and use it as common energy source?

Till date there is no such practical device available as the heat energy generated during transition from stroke to stored format will be beyond control.

2. Why it is dangerous to stand under a tree when there is lightening in the sky?

The Lightening is the output of the exchange of the negative and positive ions between two polarities across the clouds or between the heavily cloud and earth. This heavy charge causes large potential drop between the clouds or the cloud and earth. Due this potential difference the air in the passage gets ionized and the low resistance path is provided. Trees are good conductors of electricity as they are wet and rich with minerals with free ions to carry the electrical charge from one point to another. Secondly the charges get attracted to the tips of conductive parts of any object. Hence the tree tops act as sharp points to attract the charges. Hence the probability of trees providing the low resistance path of ion flow is very high. This high rush of ions from tip of tree to the ground causes very high amount of heat and due to which the tree it self burns and breaks and hence it is always harmful to stand below the tree when there is possibility of lightening.

3. Is it correct to use electricity for heating of water.

No, in India major share of electrical energy generation is taken by Thermal plants, and if we are using the electrical energy generated by thermal plants for heating purpose again then we are loosing on the energy format conversion efficiencies twice. Specifically it is not at all correct to have electrical backup in solar hot water storage tanks. First reason is that this backup is not having a close loop system for control of heater operation. Second reason is there is inadequate provision to avoid losses by radiation during storage and transfer of water. The best option is to have LPG Geysers on the taps of the bathroom. And these taps will be receiving hot water from Solar plant. During rainy season we can switch on LPG geysers based on need. The practical and easy option will be to have the instant geyser fitted on solar taps to individual bathroom with its thermostats set at +5 degree to ambient, which will sense the temperature of water and operate when needed. And being instant geyser there is no storage of hot water.

4. How the ceiling fans rotate in single direction only with out entangling the wires inside?

The ceiling fan in version of squirrel cage induction motor. The squirrel cage which is rotor does not have any electrical connection from supply. It is just like a transformer winding with output terminals shorted. The difference in normal motor and ceiling fan is that the rotor winding that is squirrel cage is circumscribing the stator winding which is totally opposite to the normal motor.

5. When the wire in dangerous?

the wire is dangerous when it is connected with supply line. It becomes harmful if the object that comes it its contact is connected to different potential. Electrical shock is resultant of current flowing through the body due the potential difference across two body parts.

6. Why there are incidences of high voltage in residential areas?

Under normal working conditions the supply company providing very high voltage happens very rarely. But it is very usual that the neutral grounding at the transformer end is very weak and under unbalanced loading conditions, which is very normal in residential area causes the rise in neutral current. The weak neutral termination or grounding allowing the neutral potential to shift away from the practical zero potential. And hence the phase with more load experience the low voltage and at the same time the phases with low load receive very high voltage which has damaging capacity.

7. How to extinguish the fire caused due to electrical short circuit.

One thing is very sure water shall not be used as extinguisher. Ideally dry sand, CO2 or DPC are used for electrical fire.