Electrostatics PYQs Set 10 (PDF)

Set 10 of 12 · Questions 271-300 of 349

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Mere Teacher · Previous Year Questions NEET Physics · Electrostatics · Set 10 (Q271-300)
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271. $In a cuboid of dimension 2L \times 2L \times L, a charge q is placed at the center of the surface 'S' having area of 4 L^{2} . The flux through the opposite surface to 'S' is given by$ (1) $\frac{q}{12 ϵ _{0}}$ (2) $\frac{q}{3 ϵ _{0}}$ (3) $\frac{q}{2 ϵ _{0}}$ (4) $\frac{q}{6 ϵ _{0}}$ 272. $A, B and C are three points in a uniform electric field. The electric potential is:$ (1) $maximum at B$ (2) $maximum at C$ (3) $same at all the three points A, B and C$ (4) $maximum at A$ 273. $A small conducting sphere of radius r is lying concentrically inside a bigger hollow conducting sphere of radius R. The bigger and smaller spheres are charged with Q and q (Q > q) and are insulated from each other. The potential difference between the spheres will be$ (1) $\frac{1}{4 π ϵ _{0}} (\frac{q}{r} - \frac{Q}{R})$ (2) $\frac{1}{4 π ϵ _{0}} (\frac{Q}{R} + \frac{q}{r})$ (3) $\frac{1}{4 π ϵ _{0}} (\frac{q}{r} - \frac{q}{R})$ (4) $\frac{1}{4 π ϵ _{0}} (\frac{q}{R} - \frac{Q}{r})$ 274. $Two electric dipoles, each of dipole moment 'P' are placed at points A (a, 0) and B (- a, 0) as shown in the figure. The work done in rotating both the dipoles through 90^{\circ} in clockwise direction is (E = Electric field)$ (1) $PE$ (2) $Zero$ (3) $2PE$ (4) $\frac{PE}{2}$ 275. $Two infinite identical charged sheets and a charged spherical body of charge density ' ρ ' are arranged as shown in figure. Then the correct relation between the electrical fields at A, B, C and D points is:$ (1) $(E_{A}) = (E_{B}); E_{C} > E_{D}$ (2) $E_{A} = E_{B}; E_{C} = E_{D}$ (3) $E_{C} \neq = E_{D}; E_{A} > E_{B}$ (4) $E_{A} > E_{B}; E_{C} = E_{D}$ 276. $Two concentric spheres kept in air have radii R and r. They have similar charge and equal surface charge density σ. The electric potential at their common centre is (ϵ_{0} = permittivity of free space)$ (1) $\frac{σ ( R + r )}{ϵ _{0}}$ (2) $\frac{σ ( R - r )}{ϵ _{0}}$ (3) $\frac{σ ( R + r )}{2 ϵ _{0}}$ (4) $\frac{σ ( R + r )}{4 ϵ _{0}}$ 277. $A capacitor of capacitance 4 μF is charged to a potential difference of 6 V with a battery. The battery is removed and in its place another capacitor of capacitance is 8 μF introduced and the circuit is closed. The potential difference attained by each of the capacitors in V is$ (1) $2$ (2) $4$ (3) $6$ (4) $8$ 278. $The electric potential at the center of two concentric half rings of radii R_{1} and R_{2}, having same linear charge density λ, is$ (1) $\frac{2 λ}{\in _{0}}$ (2) $\frac{λ}{2 \in _{0}}$ (3) $\frac{λ}{4 \in _{0}}$ (4) $\frac{λ}{\in _{0}}$ 279. $A charge Q is situated at the corner of a cube, the electric flux passed through all the six faces of the cube is$ (1) $\frac{Q}{6 ϵ _{0}}$ (2) $\frac{Q}{8 ϵ _{0}}$ (3) $\frac{Q}{ϵ _{0}}$ (4) $\frac{Q}{2 ϵ _{0}}$ 280. $The figure shows three points A, B and C in a uniform electric field (E) . The line AB is perpendicular to BC and BC is parallel to E . If V_{A}, V_{B} and V_{C} are the potentials at A, B and C respectively, then the correct option is$ (1) $V_{A} = V_{B} = V_{C}$ (2) $V_{A} = V_{B} > V_{C}$ (3) $V_{A} = V_{B} < V_{C}$ (4) $V_{A} > V_{B} = V_{C}$ 281. $Two charges Q and 4Q are separated by a distance of 6 cm . The distance of the point from 4Q at which net electric field is zero is$ (1) $2 cm$ (2) $6 cm$ (3) $8 cm$ (4) $4 cm$ 282. $A semi-infinite non-conducting rod lies along X-axis with its left end at the origin. The rod has uniform linear charge density λ. The magnitude of electric field \| E \| at a point on the Y-axis at the distance L from the origin, will be$ (1) $\frac{λ}{4 π ϵ _{0} L}$ (2) $\frac{λ}{2 π ϵ _{0} L}$ (3) $\frac{λ}{2 2 π ϵ _{0} L}$ (4) $\frac{2 λ}{π ϵ _{0} L}$ 283. $The diagrams below show regions of equipotential A positive charge is moved from A to B in each diagram.$ (1) $In all the four cases the work done is the same.$ (2) $Minimum work is required to move q in figure (I).$ (3) $Maximum work is required to move q in figure (II).$ (4) $Maximum work is required to move q in figure (III).$ 284. $An electric dipole is placed at a distance of 2 cm from an infinite plane sheet having positive charge density σ_{0} . Choose the correct option from the following.$ (1) $Potential energy and torque both are maximum.$ (2) $Torque on dipole is zero and net force is directed away from the sheet.$ (3) $Torque on dipole is zero and net force acts towards the sheet.$ (4) $Potential energy of dipole is minimum and torque is zero.$ 285. $Two large plane parallel conducting plates are kept 10 cm apart as shown in figure. The potential difference between them is V. The potential difference between the points A and B (shown in the figure) is:$ (1) $1 V$ (2) $\frac{1}{4} V$ (3) $\frac{3}{4} V$ (4) $\frac{2}{5} V$ 286. $A uniform electric field vector E exists along horizontal direction as shown. The electric potential at A is V_{A} . A small point charge q is slowly taken from A to B along the curved path as shown. The potential energy of the charge when it is at point B is$ (1) $q (V_{A} - Ex)$ (2) $q (V_{A} + Ex)$ (3) $qEx -VA$ (4) $qEx$ 287. $Three charged particles A, B and C with charges - 4 q, 2 q and -2q are present on the circumference of a circle of radius d. The charged particles A, C and center P of the circle formed an equilateral triangle as shown in figure. Electric field at O along x -direction is:$ (1) $\frac{q}{4 π ϵ _{0} d ^{2}}$ (2) $\frac{q 3}{4 π ϵ _{0} d ^{2}}$ (3) $\frac{q 3}{π ϵ _{0} d ^{2}}$ (4) $\frac{q 3}{2 π ϵ _{0} d ^{2}}$ 288. $A small uncharged conducting sphere is placed in contact with an identical sphere but having 4 \times 10^{- 8} C charge and then removed to a distance such that the force of repulsion between them is 9 \times 10^{- 3} N . The distance between them is (Take \frac{1}{4 π ϵ _{0}} as 9 \times 10^{9} in SI units)$ (1) $3 cm$ (2) $2 cm$ (3) $4 cm$ (4) $1 cm$ 289. $Two electric dipoles, A, B with respective dipole moments d_{A} = - 4 qa i and d_{B} = - 2 qa i are placed on x -axis with a separation R, as shown in the figure The distance from A at which both of them produce the same potential is:$ (1) $\frac{R}{2 + 1}$ (2) $\frac{2 R}{2 + 1}$ (3) $\frac{R}{2 - 1}$ (4) $\frac{2 R}{2 - 1}$ 290. $What will be the magnitude of electric field at point O as shown in figure? Each side of the figure is l and perpendicular to each other?$ (1) $\frac{1}{4 π ϵ _{0}} \frac{q}{l ^{2}}$ (2) $\frac{1}{4 π ϵ _{0}} \frac{q}{( 2 l ^{2} )} (22 - 1)$ (3) $\frac{q}{4 π ϵ _{0} ( 2 l ^{2} )}$ (4) $\frac{1}{4 π ϵ _{0}} \frac{2 q}{( 2 l ^{2} )} (2)$ 291. $A point charge +q is placed at the origin. A second point charge + 9 q is placed at (d, 0, 0) in Cartesian coordinate system. The point in between them where the electric field vanishes is:$ (1) $(3 d /4, 0, 0)$ (2) $(d /4, 0, 0)$ (3) $(4 d /3, 0, 0)$ (4) $(d /3, 0, 0)$ 292. $Two identical capacitors C1 and C_{2} of equal capacitance are connected as shown in the circuit. Terminals a and b of the key k are connected to charge capacitor C1 using battery of emf V volt. Now, disconnecting a and b the terminals b and c are connected. Due to this, what will be the percentage loss of energy? [NEET 2019]$ (1) $75 %$ (2) $0 %$ (3) $50 %$ (4) $25 %$ 293. $Two electric charges + 2 μC and - 4 μC are separated by a distance 3 m in air. At a point P located on the line joining the two charges and in between them, the electric potential is zero. Then the electric field at a point P (in NC^{- 1}) is$ (1) $9,000$ (2) $18,000$ (3) $12,000$ (4) $27,000$ 294. $Two ideal electric dipoles A and B, having their dipole moment p_{1} and p_{2} respectively are placed on a plane with their centres at O as shown in the figure. At point C on the axis of dipole A, the resultant electric field is making an angle of 370 with the axis. The ratio of the dipole moment of A and B, \frac{p _{1}}{p _{2}} is: (take sin 3 7^{0} = \frac{3}{5})$ (1) $\frac{3}{8}$ (2) $\frac{3}{2}$ (3) $\frac{2}{3}$ (4) $\frac{4}{3}$ 295. $Two shorts dipoles (A, B), A having charges \pm 2 μC and length 1 cm and B having charges \pm 4 μC and length 1 cm are placed with their centres 80 cm apart as shown in the figure. The electric field at a point P, equi-distant from the centres of both dipoles is____N/C.$ (1) $\frac{9}{16} 2 \times 10^{4}$ (2) $92 \times 10^{4}$ (3) $4.5 2 \times 10^{4}$ (4) $\frac{9}{16} 2 \times 10^{5}$ 296. $Six point charges each of the magnitude Q are placed at the vertices of a regular hexagon of side a as shown in the figure. Electric field intensity on the line passing through the center O and perpendicular to the plane of the figure at a large distance x (>> a) from O is ( Let, (\frac{1}{4 π ϵ _{0}} = k)$ (1) $k \times \frac{4 Qa}{x ^{3}}$ (2) $k \times \frac{2 Qa}{x ^{3}}$ (3) $k \times \frac{8 Qa}{x ^{3}}$ (4) $0$ 297. $A charge Q is distributed over three concentric spherical shells of radii a, b, c (a < b < c) such that their surface charge densities are equal to one another. The total potential at a point at distance r from their common centre, where r < a, would be$ (1) $\frac{Q}{12 π \in _{0}} \frac{ab + bc + ca}{abc}$ (2) $\frac{Q}{4 π \in _{0} ( a + b + c )}$ (3) $\frac{Q ( a + b + c )}{4 π \in _{0} ( a ^{2} + b ^{2} + c ^{2} )}$ (4) $\frac{Q ( a ^{2} + b ^{2} + c ^{2} )}{4 π \in _{0} ( a ^{3} + b ^{3} + c ^{3} )}$ 298. $A dipole is placed in an electric field as shown. In which direction will it move? [NEET 2021]$ (1) $Towards the left as its potential energy will increase$ (2) $Towards the right as its potential energy will decrease$ (3) $Towards the left as its potential energy will decrease$ (4) $Towards the right as its potential energy will increase$ 299. $σ is the uniform surface charge density of a thin spherical shell of radius R. The electric field at any point on the surface of the spherical shell is:$ (1) $σ / ϵ_{o} R$ (2) $σ / ϵ_{o}$ (3) $σ /4 ϵ_{o}$ (4) $σ /2 ϵ_{o}$ 300. $Two charges +q and -q, each 1 μC are arranged as shown in the figure. If x = 2 cm and y = 3 cm then potential difference (V_{A} - V_{B}) is$ (1) $5.4 \times 10^{2} V$ (2) $5.4 \times 10^{5} V$ (3) $5.2 \times 10^{2} V$ (4) $2.7 \times 10^{5} V$