विधुत आवेश और क्षेत्र Electric Charges & Fields | Top 40 MCQs - Day 2 | Board Exam 2023 | Gopal Sir

Electric Due To Point Charge (बिन्दु आवेश के कारण क्षेत्र)|Electric Potential (वेधयुत विभव)|Questions (प्रश्न)|Electric Potential Due To Hollow Charged Sphere (खोखले आवेशित गोले के कारण विभव)|Potential Energy Between Two Point Charges (दो बिन्दु आवेशों के मध्य संचित ऊर्जा)|Question (प्रश्न)|Dipole (द्विध्रुव)|Potential Difference In Uniform Electric Field (एक समान क्षेत्र मे विभावांतर)|OMR

A charged oil dop falls 4.0 mm in 16.0 s at constant speed in air in the absence of an electric field. The relative density of oil is 0.80, that of air is 1.3 xx 10^(-3) and the viscosityf of air is 1.8 xx 10^(-5) Ns m^(-2) . Find (i) the radius of the drop (ii) the mass of the drop. (iii) If the drop carries one electronic unit of charge and is an electric field of 2000 V cm^(-1) , what is the ratio of the force of the electric field on the drop to its weight ?

Two identical circular rings A and B of radius 30 cm are placed coaxially with their axes horizontal in a uniform electric field E. = 10^(5)N//C directed vertically upward as shown in figure. Distance between centres ofthese rings A and B is40cm. Ring A has a positive charge 10muC while ring B has a negative charge of magnitude 20muC . A particle of mass 100g and carrying a positive charge 10muC is released from rest at the centre of the ring A. Calculate its velocity when it has moved a distanceof40cm. Take g= 10m//s^(2) [6 sqrt(2) m//s]

The earth's surface has a negative surface charge density of 10^(-9) Cm^(-2) . The potential difference of 400 kV between the top of the atmosphere and the surface results (due to low conductivity of the lower atmosphere) in a current of only 1800 A over the entire globe. If there were no mechanism of sustaining atmosphereic 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 thunder storms and lightning in different parts of the globe). Radius of the earth = 6.37 xx 10^(6) m .