Electric Field and Potential Questions and Answers

Glass ball is rubbed with ebonite ball and kept at a separation of 1cm If the force of attraction between them is 10N find charge on each ball

3 A uniformly charged rod of length 4 cm and linear charge density 30 C m is placed as shown in figure Calculate the x component of electric field at point P 3yd novieP aubst to sisrices ni How b3cm 4cm 1 36 x 105 N C 2 9 x 105 N C 3 1 8 x 10 N C tristog

13 Two equally charged small balls A and B placed at a fixed distance experience a force F similar uncharged ball C after touching one of them is placed at the midpoint of the balls T force experienced by the ball A is b 3F 2 a F 2 F 4 c 2F d 4F

You are part of a design team assigned the task of making an electronic oscillator that will be the timing mechanism of a micro machine You start by trying to understand a simple model which is an electron moving along an axis through the center and perpendicular to the plane of a thin positively charged ring You need to determine how the oscillation frequency of the electron depends on the size and charge of the ring for displacements of the electron from the center of the ring which are small compared to the size of the ring A team member suggests that you first determine the acceleration of he electron along the axis as a function of the size and charge of the ring and then use that expression o determine the oscillation frequency of the electron for small oscillations

Three charges are arranged on the vertices of an equilateral triangle as shown in the figure Find the dipole moment of the 3 combination Find the electric field due to this distribution at a distance r from B along BC where r d B 20 d

A cow and a man are standing in a mead road when lightning strikes the ground nearby Who is more likely to be killed and Why Cow because man is wearing shoes 2 Cow because its legs are far apart 3 Man because cow is poor conductor of electricity 4 Both are equally likely to be killed

qis placed in a spherical cavity made in a positively charged sphere with uniform volume charge density The centres of sphere and cavity are displaced by a small distance 7 Force on charge qis A B C D do midt in the direction parallel to vector 7 in radial direction with respect to centre of cavity in a direction which depends on the magnitude of charge density in sphere direction cannot be determined

sing Thomson s model of the atom consider an atom consisting of two electrons each of charge e embedded in a sphere of charge 2e and radius R In equilibrium each electron is at distance d from the centre of the atom What is equilibrium separation between electrons P R 2 e d R d e R 3 palis D R 4

36 Eight charges having the values as shown in fig are arranged symmetrically on a circle of radium 0 1 m in air Potential at center O will be 7 C 15uC 7 C 1 252 1010v 3 252 106V 5 C 11uC 5 C 7 C 5 C 2 252 104V 4 zero

218 56 Two charges each equal to q are kept at x a and x a on the x axis A particle of mass m and charge qo q 2 is placed at the origin If charge qo is given a small displacement y a along the y axis the net force acting on the particle is proportional to JEE Main 2013 d 1 y a y b y c 1 y

A charge q is placed at rest on ve x axis at the point a 0 and another charge aq is placed at the point a a 0 Find a Coordinates x y of the point where the electric potential is zero b Nature of the equipotential surface through a general point x y in the plane c Components of forces Fx and Fy acting on an unit positive charge placed at some general point x y

9 Two identical positive charges are fixed on the y axis at equal distances from the origin U A negatively charged particle starts from negative x axis at a large distance from O moves along the x axis passes through O and moves far away from O Its acceleration a is taken as positive along its direction of motion The best graph between the particle s acceleration and its x coordinate is represented by A J a 0 B ta C a 11 D s 8

electric force experienced by any charge Ans 4 21 The electric field in a region is given by E ai bj Here a and b are constants Find the net flux passing through a square area of side L parallel to y z plane Ans aL A hollow spherical shell of radius r has a uniform charge density a It is

An infinite number of charges each of magnitude q are placed on x axis at distances of 1 2 4 8 meter from the origin respectively Find intensity of the electric field at origin Ans q 3RE towards origin

A clock face has negative charges q 2q 3q 12q fixed at the position of the corresponding numerals on the dial The clock hands do not disturb the net field due to the point charges At what time does the hour hand point in the direction of the electric field at the centre of the dial Ans 9 30

23 An infinitely long current carrying wire and a small current carrying loop are in the plane of the paper as shown The radius of the loop is a and distance of its centre from the wire is d d a If the loop applies a force F on the wire then a Fo d3 JEE Main 2019 9 Jan Shift 1 d b F 0 51