Question

Answer in your own words.

(a) How will you protect yourself from lightning?
(b) How are charges generated?
(c) In the lightning conductor, what provision is made for spreading the electricity into the ground?
(d) Why do farmers stick an iron staff into the ground while working in the field in rainy conditions?
(e) Why is lightning not seen everyday during the rainy season?

Answer 1

(a) ​Following are some safety measures to be followed to protect oneself from lightning:
If outdoor:
1. Avoid taking shelter under trees.
2. Avoid being near to any kind of metal objects which may include metal wires, fences, machinery and power appliances.
3. Take shelter inside a fully enclosed car with all the windows shut.
If indoor:
1. Turn off all the electrical appliances such as television and refrigerator.

(b) Charges are generated in an object when the object loses or gains some electrons or when there is displacement between the positive and negative charges of an object. Methods of generating charges are:

• Rubbing: When two insulators are rubbed with each other, one of them loses electrons and the other gains electrons. The one which gains electrons gets negatively charged and the other one gets positively charged.
• Conduction: When a charged body is brought in contact with an uncharged conductor, the conductor gets charged.
• Induction: When a charged body is brought near to a neutral body say a conductor or an insulator, the electrons and protons in the neutral body gets separated. Thus, the body acquires temporary charge as long as the charged body is kept near it.

(c) A pit is dug in the ground and is filled with coal and salt. A cast iron plate is placed upright in the pit and one end of the lightning conductor is connected to this plate. Also, a provision of pouring water into the pit is made. Thus, when the electric charges through the conductor is discharged into the pit, the water quickly spreads these charges into the ground and prevents damages.

(d) In rainy conditions, there is very high chance of lightning striking the Earth. So, the farmer by putting an iron staff into the ground while working in the field in rainy condition, makes sure that he and his crops remains safe in case lightning occurs. This is because the iron staff will be more prone to lightning than the crops and his body because of the iron staff being tall and metallic in nature. Thus, the electric charges from the clouds will flow to the ground through the staff without affecting the plants in case of lightning during rainy weather.

(e) For lightning to happen, there must be some minimum amount of accumulation to happen in the clouds. So, it might be possible that this limit is not achieved everyday during rainy season because of which lightning does not occur everyday. Hence, we do not see lightning everyday during the rainy season.