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-l., , The force between two charges is 120, N. If the distance between the charges, is doubled, the force will be, , (a) 60 N (6) 30N, , (c) 40N (d) 15N, , The mass of an electron is equal to, , (a) 1.602 x 107! kg, , (6) 9.11 x 107! kg, , (c) 1.678 x 102" kg, , (d) 9.11 x 10 kg, , , , As per Coulomb’s law, Q1Q2 Q1Q2, P= (b) F = —, (a) cond® () tel?, __ QiQ2 ~ -21@2, OP Traced? OY arenerd, , The electric field intensity at a point, situated 4 metres from a point charge, is 200 N/C. If the distance is reduced to, 2 metres, the field intensity will be, , (a) 400 N/C (6) 600 N/C, , (c) 800 N/C (d) 1200 N/C, Electric intensity (£) at any point in an, electric field is equal to, , (2) potential gradient, , (6) (potential gradient)”, , (c) (potential gradient)", , (d) (potential gradient)!", , The lines of force due to charged particles are, , (a) always straight, , (6) always curved, , (c) sometimes curved, , (d) none of the above, , The electric field at a point situated at, , ’ a distance d from straight charged con, ductor is, (a) proportional to d, (6) inversely proportional to d, , 3.8., , 3.10., , 3.11., , 3.12., , 3.13., , 3.14., , (c) inversely proportional to d?, , (d) none of the above, , The direction of electric field due to, , positive charge is ‘, , (a) away from the charge, , () towards the charge, , (c) both (a) and (6), , ({d) none of the above, , A field line and an equipotential sur, face are, , (a) always parallel, , (6) always at 90°, , (c) inclined at any angle 6, , (d) none of the above, , The ability of charged bodies to exert, , force on one another is attributed to the, , existence of, , (a) electrons (6) protons, , (c) neutrons (d) electric field, , If the sheet of a bakelite is inserted, , between the plates of an air capacitor,, , the capacitance will, , (a) decrease (b) increase, , (c) remains unchanged, , (d) become zero, , A capacitor stores 0.24 coulombs at 10, , volts. Its capacitance is, , (a) 0.024 F (6) 0.12 F, , (c) 0.6F (d) 0.8 F, , For making a capacitor, it is better to, , select a dielectric having, , (a) low permittivity, , (6) high permittivity, , (c) permittivity same as that of air, , (d) permittivity slightly more than that, of air :, , The units of capacitance are, , (a) volts/coulomb (6) coulombs/volt, , (c) ohms (d) henry/Wb
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15., , 16., , 17., , 18., , 19., , 21., , If three 15 pF capacitors are connected, in series, the net capacitance is, , (a) 5 uF (6) 30 pF, , (c) 45 pF (d) 50 pF, , If three 10 uF capacitors are connected, in parallel, the net capacitance is, , (a) 20 pF (6) 30 uF, , (c) 40 pF (d) 50 pF, , A dielectric material must be, (a) resistor (6) insulator, , (c) good conductor (d) semi-conductor, , Anelectrolytic capacitor can be used for, , (a) D.C. only (6) AC. only, , (c) both D.C. as well as A.C., , The capacitance of a ers is not, , affected by, , (a) distance between plates, , (5) area of plates, , (c) thickness of plates, , (d) all of the above, , The capacitance ofa cylindrical capacitor, , is ~ by, , (a) (oy 2me0er, men ra/ri log r2/ri, , PP 0 el, loge r2/ri loge r2/ri, , Which of the following is not a vector ?, (a) Linear momentum, , (6) Angular momentum, , (c) Electric field, , (d) Electric potential, , Electric flux in coulombs emanating, from any surface of a cube containing, C coulombs of charge at its centre is, , Q 4nQ, (a) 4 (b) 6E, Q, (c) 3 (d) Q, , Two metal plates distance ‘d’ apart, form a capacitor of value C farads., Another metal plate of thickness d/2, and of the same area is inserted in, between these two plates, capacitance, of this three plate capacitor wi, , (a) 4 (2, , (c) 1/2 (d) 1/4, , 3.24., , 3.25., , 3.26., , 3.27., , 3.28., , 3.29., , Electric field inside a hollow metallic, charged sphere is, , (a) increasing towards centre, , (b) decreasing towards centre, , (c) zero, , (d) none of the above, , A conducting body has surface charge, density of o coulombs/m?, the field in, tensity at its surface will be, o ‘a, oF, (a) Porn (6) me, (c) sore (, e08r, , Two plates of a parallel plate capacitor, , after being charged from a constant, , voltage source are separated apart by, , means of insulated handles, then the, , (a) Voltage across the plates increases, , (b) voltage across the plates decreases, , (c) charge on the capacitor decreases, , (d) charge on the capacitor increases, , If A.C. voltage is applied to capacitive, , circuit, the alternatingcurrent can flow, , in the circuit because, , (a) varying voltage produces the charging and dicharging currents, , (6) of high peak value, , (c) charging current can flow, , (d) discharge current can flow, , Voltage applied across a ceramic dielectric produces an electrolytic field, 100 times greater than air. What will, be the value of dielectric constant ?, , (a) 50 (6) 100, , (c) 150 (d) 200, , Which of the following statements is, correct 2, , (a) Air capacitors have a blackband to, indicate the outside foil, , (6) Electrolytic capacitor must be con- ‘, nected in the correct polarity, , (c) Ceramic capacitors must be connected in the correct polarity, , (d) Mica capacitors are available in, capacitance value of 1 to 10 uF
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3.30. The dissipation factor of a good di, electric is of the order of, (a) 0.0002 (6) 0.002, (c) 0.02 (d) 0.2, , 3.31. “The total electric flux through any, closed surface surrounding charges is, equal to the amount of charge enclosed”., , The above statement is associated with, (a) Coulomb’s square law, (6) Gauss’s law, (c) Maxwell's first law, (d) Maxwell’s second law, , 32. Three capacitors each of the capacity C, are given. The resultant capacity 2/3 C, can be obtained by using them, (a) allinseries (6) all in parallel, (c) two in parallel and third in series, , with this combination, (d) two in series and third in paraliel, across this combination, , 33. For which of the following parameter, variation, the capacitance of the, capacitor remains unaffected ?, , (a) Distance between plates, (6) Area of the plates, , (c) Nature of dielectric, , (d) Thickness of the plates, , 84. Which of the following statement is, true?, (a) The current in the discharging, capacitor grows linearly, (6) The current in the dicharging, capacitor grows exponentially, (c) The current in the discharging, capacitor decays exponentially, (d) The current in the discharging, , capacitor decreases constantly, .35. Which of the following expression is, correct for electric field ?, (a) E= Die (b) E= le, (c) E=2D (2) E =xD*, , 36. In a capacitor the electric charge is, stored in, (a) metal plates (6) dielectric, (c) both (a) and (6), (d) none of the above, , 3.37., , 3.39., , 3.40., , 341., , 3.42., , 3.43., , Which of the following materials has, tant?, , (a) Glass (6) Vacuum, , (c) Ceramics (d) Oil, , Which of the following capacitors will, have the least variation ?, , (a) Paper capacitor, , (6) Ceramic capacitor, , (c) Silver plated mica capacitor, , (d) None of the above, , Which of the following statements is, , incorrect ?, , (a) The leakage resistance of ceramic, capacitors is generally high, , (6) The stored energy in a capacitor, decreases with reduction in value of, capacitance, , (c) The stored energy in a capacitor, increases with applied voltage, , (d) A wire cable has distributed capacitance between the conductors, , Which of the following capacitors has, relatively shorter shelf life ?, , (a) Mica capacitor, , (6) Electrolytic capacitor, , (c) Ceramic capacitor, , (d) Paper capacitor, , The sparking between two electrical, contacts can be reduced by inserting a, (a) capacitor in parallel with contacts, (6) capacitor in series with each contact, (c) resistance in line, , (d) none of the above, , In the case of a lossy capacitor, its, series equivalent resistance value will, , be, , (a) small (6) very small, , (c) large (d) zero, , The power dissipated in a pure, capacitor is, , (a) zero, , (6) proportional to applied voltage, , (c) proportional to value of capacitance, (d) both (5) and (c) above