Saved Bookmarks
| 1. |
Answer carefully : (a) Two large conducting spheres carrying charges Q_(1) and Q_(2) are brought close to each other. Is the magnitude of electrostaticforce between them exactly given by (Q_(1) Q_(2))/(4pi in_(0) r^(2)) where r is distance between their centers ? (b) If Coulomb law involved 1//r^(3) dependence (Instead of 1//r^(3)). would Gauss's law be still true ? (c) A small test charge is releasedat rest at a pointin an electrostatic fieldconfiguration. Will it travel along the line of force passing through that point ? (d) What is the work done by the field of a nucleus in a completecircualr orbits of electron ? What if the orbits is elliptical ? (e) We knowthat electric field is discontinnous across the surfaceof a chargedconductor conductor. Is electricpotential also discontinous there ? (f) What meaning would you give to the capacity fo a singleconductor ? (g) Guess a possible reason why waterhas a muchgreaterdielectric constant K = 80 than, say mica (K = 6). |
|
Answer» Solution :(a) When the chargedspheres are brought close together, the charge DISTRIBUTIONS on them become non-uniform. Therefore, Coulomb's LAW is not valid. Hencethe magnitude of force is not given exactly by this formula. (b) No. Gauss's law will not true if Coulomb's law involve `1//r^(3)` dependance instead of `1//r^(2)` dependence. (C) The line of force given the direction of acceleration of charge. If the ELECTRIC line of force si linear, the TEST charge will movealong the line. If the line of force is non linear, the charge will not go along the line. (d) As forcedue tothe fieldis directedtowardsthe nucleas ,and the electrondoes not movein the direction fo this force, therefore work donesi zero whenthe orbits is circular. This is trueeven whenorbits is ellipiticalas electricforces are conservative forces. (e) No, electric potential is contionous. (f) The capacity fo a singleconductorimplies that thesecond conductoris at infinity. (g) This is because a molecule of waterin its normal statehas an usysmmetrical shape and, therfore it has a permanenet dipole moment. |
|