# Practice Test

Q1) How many electrons will constitute a charge of one coulomb ? Show Answer

Q2) S.I unit of permittivity is Show Answer

Q3) The ratio of the forces between two small spheres with constant charge 'a' in air and 'b' in a medium of dielectric constant k is Show Answer

Q4) The force between two electrons separated by a distance 'r' is proportional to Show Answer

Q5) The relation between permittivity of medium, permittivity of vaccum and dielectric constant is given as Show Answer

Q6) Three charges 4q, Q and q are in a straight line in the position 0,l/2 and l respectively. The resultant force on q will be zero if Q = Show Answer

Q7) Two small spheres each having the charge +Q are suspended by insulating threads of length L from a hook. This arrangement is taken in space where there is no gravitational effect then the angle between the two suspensions and the tension in each will be Show Answer

Q8) Linear charge density for circle of radius r is Show Answer

Q9) The number of electrons carrying a charge of 8 C is Show Answer

Q10) The minimum magnitude of charge that a particle can have is Show Answer

Q11) A charge q is placed at the centre of the line joining two equal charges Q. The system of the three charges will be in equilibrium if q is equal to Show Answer

Q12) Unit of surface charge density is Show Answer

Q13) The magnitude of electric field intensity E is such that an electron placed in it would experience force equal to its weight given by Show Answer

Q14) Two charge +4e and +e are at distance x apart. At what distance a charge q must be placed from charge +e so that it is in equilibrium ? Show Answer

Q15) Intensity of an electric field E due to a dipole, depends on distance 'r' as Show Answer

Q16) The acceleration of a particle of charge of 0.5 C and 500 mg mass kept in an electric field of intensity 200 N/C is Show Answer

Q17) The SI unit and dimensions of dipole moment respectively are Show Answer

Q18) In vector form dipole moment can be expressed as

Q19) When axis of electric dipole lies along the direction of field then torque acting in dipole is Show Answer

Q20) Which of the following charges can form an electric dipole ? Show Answer

Q21) The value of electric potential at any point due to any electric dipole is Show Answer

Q22) For a two charge system separated by distance r, the potential energy is Show Answer

Q23) Dimensions of electric potential is Show Answer

Q24) The potential at a point due to an electric dipole will be maximum and minimum when the angle between the axis of the dipole and the line joining the point to the dipole are Show Answer

Q25) When a charged particle of charge q and mass m is accelerated from rest by a potential difference V, then velocity attained by particle is Show Answer

Q26) SI unit of electric flux is Show Answer

Q27) The electric flux through a surface is maximum when angle between electric field E and normal to area S is Show Answer

Q28) The SI unit of electric flux density is Show Answer

Q29) When surface is parallel to electric field, the electric flux becomes Show Answer

Q30) A charge Q is divided into two charges q and (Q-q). What should be the relation between Q and q so that force between q and (Q-q) is maximum ? Show Answer

Q31) Electric charges q, q and -2q are placed at the corners of an equilateral triangle ABC of side l. The magnitude of electric dipole moment of the system is Show Answer

Q32) A current of 5 A flows through a conductor for 1 s then how many electrons would flow through the conductor in the same time ? Show Answer

Q33) The moment of couple acting on an electric field is maximum when Show Answer

Q34) When a charge of 3 coulomb is placed in a uniform electric field it experience a force of 3000 N with in this field, the potential difference between two points seperated by a distance of 1 cm is Show Answer

Q35) Electrostatic means study of Show Answer

Q36) Which of the following is NOT an example of static electricity ? Show Answer

Q37) When a glass rod is rubbed with silk cloth, then Show Answer

Q38) Frictional electricity is produced on the two objects due to Show Answer

Q39) Like charges repel each other and unlike charges attract each other. This phenomenon was proved by Show Answer

Q40) The positive and negative names of the charges were given by Show Answer

Q41) The property of attraction or repulsion acquired by the material body when it rubbed with another body is Show Answer

Q42) When the distance between the charged particles is halved the force between them becomes Show Answer

Q43) There are two charges +1 micro coulombs and +3 micro coulombs. The ratio of the forces acting on them will be Show Answer

Q44) Dielectric constant of a medium is also known as Show Answer

Q45) Which of the following is NOT true about dielectric constant ? Show Answer

Q46) Force between two charges, when placed in free space is 10 N. If they are in a medium of relative permittivity 5, the force between them will be Show Answer

Q47) The superposition of forces is a method to find force on a charge when Show Answer

Q48) Volume charge density is Show Answer

Q49) Charge per unit area is called as Show Answer

Q50) We can define the term charge density when distribution of charge is Show Answer

Q51) When the charge is not accumulated in some part of a conductor but spread evenly then it is called a Show Answer

Q52) When any physical quantity exists in the form of discrete packets it is said to be Show Answer

Q53) The unit of intensity of electric field is Show Answer

Q54) The electric field inside a spherical shell of uniform surface charge density is Show Answer

Q55) The unit of electric field is NOT equivalent to Show Answer

Q56) Electric lines of force about negative point charge are Show Answer

Q57) An electric lines of force is Show Answer

Q58) Which of the following is NOT true about electric lines of forces ? Show Answer

Q59) An electric dipole is kept in non-uniform electric field. It experiences Show Answer

Q60) A region surrounded a stationary electric dipole has Show Answer

Q61) The work done in bringing a charge from infinity to any point in the field is Show Answer

Q62) The electric potential due to a charged metallic sphere is constant Show Answer

Q63) A hollow metal sphere of radius 10 cm is charged such that the potential on its surface is 80 volt. The potential at the centre of the sphere is Show Answer

Q64) Which of the following is NOT true about electric potential ? Show Answer

Q65) The electric potential is independent of which of the following ? Show Answer

Q66) The rate of change of potential with respect to distance in direction of electric intensity is called Show Answer

Q67) An electric dipole has the magnitude of charge q and dipole moment p. It is placed in a uniform electric field. If its dipole moment is along the direction of the field then the force on it and its potential energy are rspectively Show Answer

Q68) Coulombs law is applicable for stationary point charges and not for the extended bodies. This statement is Show Answer

Q69) Two bodies get charged when they rubbed with each other due to transfer of Show Answer

Q70) The work done to move a charge from one point to another is Show Answer

Q71) As we move in the direction of electric intensity the electrical potential Show Answer

Q72) Electric potential due to positive and negative charges respectively is Show Answer

Q73) Example of equipotential surface is Show Answer

Q74) If a unit charge is taken from one part to another over an equipotential surface Show Answer

Q75) The law governing the force between electric charge is known as Show Answer

Q76) Which of the following represents electric field neither constant in magnitude nor in direction ? Show Answer

Q77) A unit charge is taken from one point to another over an equipotential surface. Work done in this process will be : Show Answer

Q78) A parallel plate capacitor with oil as dielectric( dielectric constant of oil K=2) has a capacitance C. If the oil is removed, then capacitance of a capacitor becomes: Show Answer

Q79) Two point charges +q and -q are held fixed at (-d,0) and (d,0) respectively of a (X,Y) coordinate system. Then Show Answer

Q80) The respective radii of the two spheres of a spherical condenser are 12 cm and 9 cm. The dielectric constant of the medium between them is 6. The capacity of the condenser will be Show Answer

Q81) An uncharged conductor A connected with earth is brought with another charged conductor B. Thereby : Show Answer

Q82) A condenser having capacity 2.0 microfarad is charged to 200 volt and then the plates of the capacitor are connecated to a resistance wire. Thus, heat produced in joule will be: Show Answer

Q83) Two charges Q and q are placed at a distance d from each other. If the magnitude of each charge is doubled and the distance between them halved, the force between them will be: Show Answer

Q84) Two small spheres each carrying a charge (q) are placed (r) meter apart. If one of the spheres is taken around the other in a circular path, then work done will be equal to : Show Answer

Q85) The electrostatic energy stored in a capacitor is : Show Answer

Q86) The electric field required to keep a water drop of mass m just to remain suspended, when charged with one electron is : Show Answer

Q87) A point charges Q and -2Q are placed at some distance apart. If the electric field at the location of Q is E, then the electric field at the location of -2Q will be: Show Answer

Q88) A charge (q ) is enclosed in a cube. What is electric flux associated with one of the faces of the cube? Show Answer

Q89) A uniform electric field pointing in positive X - direction exists in a region. Let A be the origin, B be the point on x - axis at X = +1 cm and C be the point on the y - axis at Y = +1 cm. Then the potentials at the points A, B and C satisfy : Show Answer

Q90) Three positive charges of equal value q are placed at the vertices of an equilateral triangle. The resulting lines of force should be sketched as in (see fig.) : Show Answer

Q91) A charge of Q coulomb is placed on a solid piece of metal of irregular shape. The charge will distribute itself : Show Answer

Q92) If a charged spherical conductor of a radius 10 cm has potential V at point distant 5 cm from its centre, then the potential at a point distant 15 cm from the centre will be : Show Answer

Q93) A point Q lies on the perpendicular bisector of an electric dipole of dipole moment p. If the distance of Q from the dipole is r (much larger than the size of the dipole) then electric filed at Q is proportional to : Show Answer

Q94) The capacity of a conductor does not depend upon : Show Answer

Q95) If the distance parallel plates of a capacitor is halved and dielectric constant is doubled then the capacitance : Show Answer

Q96) If the accelerating potential of an electron is doubled, then its velocity will : Show Answer

Q97) A point Q lies on the perpendicular bisector of an electrical dipole moment p. If the distance of Q from the dipole is r (much larger than the size of the dipole), then electric field at Q is proportional to : Show Answer

Q98) If a charged spherical conductor of radius 10 cm has potential V at a point distance 5 cm from its centre, then the potential at a point distant 15 cm from the centre will be : Show Answer

Q99) The number of electrons to be put on spherical conductor of radius 0.1 m. To produce an electric field of 0.036 N/C just above its surface, is : Show Answer

Q100) Two identical mercury drops, each of radius r are charged to the same potential V. If the mercury drops coalesce to form a big drop, each of radius R, then potential of the combined drop will be Show Answer

Q101) If identical charges (-q) are placed at each corner of a cube of side b, then electric potential energy of charge (+q) which is placed at centre of the cube will be : Show Answer

Q102) If the distance between the plates of a parallel plate condenser is halved and the dielectric is doubled, then its capacity increases by : Show Answer

Q103) Two equal point charges are fixed at x = -a and x = +a on the X-axis. Another point charge Q is placed at the origin. The change in the electrical potential energy of Q, when it is displayed by a small distance x along the X-axis, is approximately proportional to : Show Answer

Q104) A metallic particle having no net charge is placed near a finite metal plate carrying a positive charge. The electric force on the particle will be : Show Answer

Q105) A pellet carrying a charge of 0.5 coulomb is accelerated through a potential of 2000 volt. It attains a kinetic equal to : Show Answer

Q106) Proton is nearly 1836 times more massive than the electron. The Coulomb force of repulsion between two protons separated by a finite distance is F. The electrostatic force between two electrons separated by the same distance is : Show Answer

Q107) The capacity of a parallel plate capacitor depends on : Show Answer

Q108) Two point charges are +2C and +6C repel each other with a force of 12 newton. If a charge of -4C is given to each of these charges the force now is : Show Answer

Q109) The electrostatic capacitance depends on : Show Answer

Q110) A charge q is located at the centre of a cube. The electric flux through any face is : Show Answer

Q111) An electric dipole placed in a non-uniform electric field experiences : Show Answer

Q112) If an uncharged capacitor is charged by connecting it to a battery, then the amount of energy lost as heat is : Show Answer

Q113) A metallic shell has a point charge 'q' kept inside its cavity. Which one of the following diagram correctly represents the electric lines of forces ? Show Answer

Q114) A parallel plate capacitor has a capacitance of 100 pF, when the plates of the capacitor are separated by a distance of t. Then, a metallic foil of thickness t/3 is introduced between the plates. The capacitance will then become : Show Answer

Q115) Two charges -10, + 20 e.s.u are separated by 1 m. The electric potential will be zero at a point : Show Answer

Q116) Two equal small metal balls are given charges equal to 10 e.s.u. and -20 e.s.u. They are allowed to touch each other and are again separated to the same distance as before. The ratio of the force between the two balls in the two cases respectively is : Show Answer

Q117) A variable parallel plate capacitor and an electroscope are connected in parallel to battery. The reading of the electroscope would be decreased by :
(i) increasing the area of overlap of the plates.
(ii) placing a block of paraffin wax between the plates.
(iii) decreasing the distance between the plates.
(iv) decreasing the battery potential Then state if : Show Answer

Q118) Dielectric polarisation means: Show Answer

Q119) A parallel plate capacitor has a capacitance of 100 pF, when the plates of the capacitor are separated by a distance of t. Then a metallic foil of thickness t/3 is introduced between the plates. Show Answer

Q120) Using mass (M), length (L), time (T) and current (A) as fundamental quantities, the dimensions of permittivity is : Show Answer

Q121) Equipotential surfaces associated with an electric field, which is increasing in magnitude along the x-direction, are : Show Answer

Q122) The electric field (E) due to a uniformly charged sphere of radius (R) as function of the distance from its centre (r) is represented graphically by Show Answer

Q123) An electric dipole has the magnitude of its charge as q, and its dipole moment as p. It is placed in a uniform electric field E. If its dipole moment is along the direction of the field, then force acting on it and its potential energy are respectively : Show Answer

Q124) A thin aluminium sheet is placed between the plates of a parallel capacitor. Its capacitance will : Show Answer

Q125) A simple pendulum has time period T. The bob is given negative charge and surface below it is given positive charge. The new time period will be : Show Answer

Q126) Two insulated charged spheres of radii 20 cm and 25 cm respectively and having an equal charge Q are connected by a copper wire, then they are separated by a copper wire, then they are separated : Show Answer

Q127) Work done in moving a positive charge on an equipotential surface is : Show Answer

Q128) The capacity of a condenser in which a dielectric of dielectric constant 5 has been used, is C. If the dielectric is replaced by another with dielectric constant 20, the capacity will become: Show Answer