The top of the atmosphere is about 400 kV with respect to the surface of earth, corresponding to an electric field that decreases with altitude. Near the surface of the earth the field is about 100 V $m^{- 1}$ , but still dont get an electric shock, as we set out of our houses in to open because :(assume the house is free from electric field)

Our body is a perfect insulator

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Our body and ground form an equipotential surface

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The original equipotential surfaces of open air remain same

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None of the above

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Solution

The correct option is D Our body and ground form an equipotential surface
Dry atmosphere is not a conductor. Only when top of the atmosphere increases to a very large value and there is moisture in the air, the lightning strikes the ground. Since, $400 k V$ is not very high voltage so, it will not strive the ground.

Since, our body and the surface of earth, both are conducting, therefore our body and the ground form an equipotential surface. As we step out in to the open from our house, the original equipotential surfaces of open air change, keeping our body and the ground at the same potential. That is why we do not get an electric shock.

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Q. The top of the atmosphere is about

400 k V

with respect to the surface of earth, corresponding to an electric field that decreases with altitude. Near the surface of earth the field is about

100 V m^{- 1}

, but still don't get an electric shock, as we set out of our houses in to open because (assume the house is free from electric field)

Q. The top of the atmosphere is about 400 kV with respect to the surface of the earth, corresponding to an electric field that decreases with altitude. Near the surface of the earth, the field is about

100 V m^{- 1}

. Still, we do not get an electric shock as we step out of our house into the open house, because (assume the house to be a steel cage so that there is no field inside)

Q. The top of the atmosphere is at about

400 k V

with respect to the surface of the earth, corresponding to an electric field that decreases with altitude. Near the surface of the earth, the field is about

100 V m^{- 1}

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Q. Answer the following:

(a) The top of the atmosphere is at about 400 kV with respect to the surface of the earth, corresponding to an electric field that decreases with altitude. Near the surface of the earth, the field is about

100 V m^{- 1}

. Why then do we not get an electric shock as we step out of our house into the open? (Assume the house to be a steel cage so there is no field inside!)

(b) A man fixes outside his house one evening a two metre high insulating slab carrying on its top a large aluminium sheet of area $1 m^{2}$ . Will he get an electric shock if he touches the metal sheet next morning?

(c) The discharging current in the atmosphere due to the small conductivity of air is known to be 1800 A on an average over the globe. Why then does the atmosphere not discharge itself completely in due course and become electrically neutral? In other words, what keeps the atmosphere charged?

(d) What are the forms of energy into which the electrical energy of the atmosphere is dissipated during a lightning?
(Hint: The earth has an electric field of about 100 V $m^{- 1}$ at its surface in the downward direction, corresponding to a surface charge density = $- 10^{- 9}$ C $m^{- 2}$ . Due to the slight conductivity of the atmosphere up to about 50 km (beyond which it is good conductor), about + 1800 C is pumped every second into the earth as a whole. The earth, however, does not get discharged since thunderstorms and lightning occurring continually allover the globe pump an equal amount of negative charge on the earth.)

Q. Answer the following: (a) The top of the atmosphere is at about 400 kV with respect tothe surface of the earth, corresponding to an electric field thatdecreases with altitude. Near the surface of the earth, the fieldis about 100 Vm–1. Why then do we not get an electric shock aswe step out of our house into the open? (Assume the house tobe a steel cage so there is no field inside!) (b) A man fixes outside his house one evening a two metre highinsulating slab carrying on its top a large aluminium sheet ofarea 1m2. Will he get an electric shock if he touches the metalsheet next morning? (c) The discharging current in the atmosphere due to the smallconductivity of air is known to be 1800 A on an average overthe globe. Why then does the atmosphere not discharge itselfcompletely in due course and become electrically neutral? Inother words, what keeps the atmosphere charged? (d) What are the forms of energy into which the electrical energyof the atmosphere is dissipated during a lightning?(Hint: The earth has an electric field of about 100 Vm–1 at itssurface in the downward direction, corresponding to a surfacecharge density = –10–9 C m–2. Due to the slight conductivity ofthe atmosphere up to about 50 km (beyond which it is goodconductor), about + 1800 C is pumped every second into theearth as a whole. The earth, however, does not get dischargedsince thunderstorms and lightning occurring continually allover the globe pump an equal amount of negative charge onthe earth.)

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