Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • NCERT
  • The earth’s surface has a negative surface charge density of 10 –9 C m –2. The potential difference of 400 kV between the top of the atmosphere and the surface results (due to the low conductivity of the lower atmosphere) in a current of only 1800 A over

3.14 The earth’s surface has a negative surface charge density of 10-9 C m-2. The potential difference of 400 kV between the top of the atmosphere and the surface results (due to the low conductivity of the lower atmosphere) in a current of only 1800 A cover the entire globe. If there were no mechanism of sustaining atmospheric electric field, how much time (roughly) would be required to neutralise the earth’s surface? (This never happens in practice because there is a mechanism to replenish electric charges, namely the continual thunderstorms and lightning in different parts of the globe). (Radius of earth = 6.37 × 10 6 m.)

Answers (1)

best_answer

Given,

Surface Charge density of earth \rho = 10^{-9}C m^{-2}

Current over the entire globe = 1800 A

Radius of earth, r = 6.37 x 10^6 m

\therefore The surface area of earth A = 4\pi r^2 

=  4\pi (6.37\times10^6 )^2   = 5.09 \times 10^{14} m^2

Now, Charge on the earth surface,   q=\rho\times A 

Therefore,

 q=\dpi{100} 5.09 \times 10^{5} C

Let the time taken to neutralize earth surface be  t

\therefore Current I = q / t

\implies  t = 282.78 s.

Therefore, time take to neutralize the Earth's surface is 282.78 s

Posted by

HARSH KANKARIA

View full answer

Crack CUET with india's "Best Teachers"

  • HD Video Lectures
  • Unlimited Mock Tests
  • Faculty Support
cuet_ads

Similar Questions

Trending Articles/News

anam-khan

CBSE date sheet 2025 for Classes 10, 12 likely in November last week: Reports
anam-khan

CBSE allows Class 10, 12 students from disaffiliated schools to appear for board exam 2025 from same school
anam-khan

CBSE withdraws affiliation of 21 schools, downgrades 6 schools in two states; most in Delhi

Latest Question