MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 93 Mcqs, each offering curated multiple-choice questions to sharpen your Physics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Two point charges \[100\,\mu \,C\] and \[5\,\mu \,C\] are placed at points \[A\] and \[B\] respectively with \[AB=40\,cm\]. The work done by external force in displacing the charge \[5\,\mu \,C\] from \[B\] to \[C\], where \[BC=30\,cm\], angle \[ABC=\frac{\pi }{2}\] and \[\frac{1}{4\pi {{\varepsilon }_{0}}}=9\times {{10}^{9}}N{{m}^{2}}/{{C}^{2}}\] [MP PMT 1997] |
| A. | \[9\,J\] |
| B. | \[\frac{81}{20}J\] |
| C. | 2h |
| D. | \[-\frac{9}{4}J\] |
| Answer» E. | |
| 2. |
A particle \[A\] has charge \[+q\] and a particle \[B\] has charge \[+\,4q\] with each of them having the same mass \[m\]. When allowed to fall from rest through the same electric potential difference, the ratio of their speed \[\frac{{{v}_{A}}}{{{v}_{B}}}\] will become [BHU 1995; MNR 1991; UPSEAT 2000; Pb PET 2004] |
| A. | \[2:1\] |
| B. | \[1:2\] |
| C. | If assertion is true but reason is false. |
| D. | \[4:1\] |
| Answer» C. If assertion is true but reason is false. | |
| 3. |
Charges of \[+\frac{10}{3}\times {{10}^{-9}}C\] are placed at each of the four corners of a square of side \[8\,cm\]. The potential at the intersection of the diagonals is [BIT 1993] |
| A. | \[150\sqrt{2}\,volt\] |
| B. | \[1500\sqrt{2}\,volt\] |
| C. | \[11\,V/m\] |
| D. | \[900\,volt\] |
| Answer» C. \[11\,V/m\] | |
| 4. |
Two charges are at a distance ?d? apart. If a copper plate (conducting medium) of thickness \[\frac{d}{2}\] is placed between them, the effective force will be [UPSEAT 2001; J & K CET 2005] |
| A. | 2F |
| B. | F / 2 |
| C. | \[\frac{q}{{{d}^{3}}}\] |
| D. | \[\sqrt{2}F\] |
| Answer» D. \[\sqrt{2}F\] | |
| 5. |
A charge \[Q\] is divided into two parts of \[q\] and \[Q-q\]. If the coulomb repulsion between them when they are separated is to be maximum, the ratio of \[\frac{Q}{q}\] should be [MP PET 1997] |
| A. | 2 |
| B. | \[1/2\] |
| C. | \[\propto r\] |
| D. | \[1/4\] |
| Answer» B. \[1/2\] | |
| 6. |
Two identical point charges are placed at a separation of d. P is a point on the line joining the charges, at a distance x from any one charge. The field at P is E, E is plotted against x for values of x from close to zero to slightly less than d. Which of the following represents the resulting curve |
| A. | |
| B. | |
| C. | If Assertion is correct but Reason is incorrect. |
| D. | |
| Answer» E. | |
| 7. |
Point charge \[q\] moves from point \[P\] to point \[S\] along the path \[PQRS\] (figure shown) in a uniform electric field \[E\] pointing coparallel to the positive direction of the \[X-\]axis. The coordinates of the points \[P,\,Q,\,R\] and \[S\] are \[(a,\,b,\,0),\ (2a,\,0,\,0),\ (a,\,-b,\,0)\] and \[(0,\,0,\,0)\] respectively. The work done by the field in the above process is given by the expression [IIT 1989] |
| A. | \[qEa\] |
| B. | \[-qEa\] |
| C. | Fe |
| D. | \[qE\sqrt{[{{(2a)}^{2}}+{{b}^{2}}]}\] |
| Answer» C. Fe | |
| 8. |
The electric intensity due to an infinite cylinder of radius and having charge q per unit length at a distance from its axis is [MP PMT 1993; AFMC 2000] |
| A. | Directly proportional to |
| B. | Directly proportional to |
| C. | is balanced by the viscous drag produced by the atmosphere |
| D. | Inversely proportional to |
| Answer» D. Inversely proportional to | |
| 9. |
Electric field at a point varies as for |
| A. | An electric dipole |
| B. | A point charge |
| C. | decrease by 0.5% |
| D. | A line charge of infinite length |
| Answer» D. A line charge of infinite length | |
| 10. |
Two metal spheres of radii \[{{R}_{1}}\] and \[{{R}_{2}}\] are charged to the same potential. The ratio of charges on the spheres is [KCET 1999] |
| A. | \[\sqrt{{{R}_{1}}}\ :\ \sqrt{{{R}_{2}}}\] |
| B. | \[{{R}_{1}}\ :\ {{R}_{2}}\] |
| C. | \[\sqrt{{{A}_{2}}}/\sqrt{{{A}_{1}}}\] |
| D. | \[R_{1}^{3}:\ R_{2}^{3}\] |
| Answer» C. \[\sqrt{{{A}_{2}}}/\sqrt{{{A}_{1}}}\] | |
| 11. |
An electron enters between two horizontal plates separated by 2mm and having a potential difference of 1000V. The force on electron is [JIPMER 1999] |
| A. | \[8\times {{10}^{-12}}\]N |
| B. | \[8\times {{10}^{-14}}\]N |
| C. | In between zero and maximum |
| D. | \[8\times {{10}^{14}}\] N |
| Answer» C. In between zero and maximum | |
| 12. |
How much kinetic energy will be gained by an \[\alpha -\]particle in going from a point at \[70\,V\] to another point at \[50\,V\] [RPET 1997] |
| A. | \[40\,eV\] |
| B. | \[40\,keV\] |
| C. | \[\sqrt{2}-1\] |
| D. | \[0\,eV\] |
| Answer» B. \[40\,keV\] | |
| 13. |
Four charges are placed on corners of a square as shown in figure having side of \[5\,cm\]. If Q is one microcoulomb, then electric field intensity at centre will be [RPET 1999] |
| A. | \[1.02\times {{10}^{7}}N/C\] upwards |
| B. | \[2.04\times {{10}^{7}}N/C\] downwards |
| C. | 0.005 |
| D. | \[1.02\times {{10}^{7}}N/C\] downwards |
| Answer» B. \[2.04\times {{10}^{7}}N/C\] downwards | |
| 14. |
A charged water drop whose radius is \[0.1\,\mu m\] is in equilibrium in an electric field. If charge on it is equal to charge of an electron, then intensity of electric field will be \[(g=10\,m{{s}^{-1}})\] [RPET 1997] |
| A. | \[1.61\,N/C\] |
| B. | \[26.2\,N/C\] |
| C. | Liquid of low viscosity and low density flowing through a pipe of large radius |
| D. | \[1610\,N/C\] |
| Answer» D. \[1610\,N/C\] | |
| 15. |
A particle of mass \[m\] and charge \[q\] is placed at rest in a uniform electric field \[E\] and then released. The kinetic energy attained by the particle after moving a distance \[y\] is [CBSE PMT 1998; Kerala PMT 2005] |
| A. | \[qE{{y}^{2}}\] |
| B. | \[q{{E}^{2}}y\] |
| C. | Lowers |
| D. | \[{{q}^{2}}Ey\] |
| Answer» D. \[{{q}^{2}}Ey\] | |
| 16. |
The electric potential \[V\] is given as a function of distance \[x\] (metre) by \[V=(5{{x}^{2}}+10x-9)\,volt\]. Value of electric field at \[x=1\] is [MP PET 1999] |
| A. | \[20\,V/m\] |
| B. | \[6\,V/m\] |
| C. | 0.12569444444444 |
| D. | \[-23\,V/m\] |
| Answer» B. \[6\,V/m\] | |
| 17. |
Two insulated charged conducting spheres of radii \[20\,cm\] and \[15\,cm\]respectively and having an equal charge of \[10\,C\] are connected by a copper wire and then they are separated. Then [MP PET 1997] |
| A. | Both the spheres will have the same charge of \[10\,C\] |
| B. | Surface charge density on the \[20\,cm\] sphere will be greater than that on the \[15\,cm\] sphere |
| C. | \[5\,N/m\] |
| D. | Surface charge density on the two spheres will be equal |
| Answer» D. Surface charge density on the two spheres will be equal | |
| 18. |
In the figure the charge \[Q\] is at the centre of the circle. Work done is maximum when another charge is taken from point \[P\] to |
| A. | \[K\] |
| B. | \[L\] |
| C. | Will rise to less height than at atmospheric pressure |
| D. | \[N\] |
| Answer» B. \[L\] | |
| 19. |
A flat circular disc has a charge \[+Q\] uniformly distributed on the disc. A charge \[+q\] is thrown with kinetic energy \[E\]towards the disc along its normal axis. The charge \[q\]will [MP PMT 1995] |
| A. | Hit the disc at the centre |
| B. | Return back along its path after touching the disc |
| C. | Capillary action |
| D. | Any of the above three situations is possible depending on the magnitude of E |
| Answer» E. | |
| 20. |
Deutron and \[\alpha -\]particle are put \[1\,{AA}\] apart in air. Magnitude of intensity of electric field due to deutron at \[\alpha -\]particle is [MP PET 1995] |
| A. | Zero |
| B. | \[2.88\times {{10}^{11}}\,newton/coulomb\] |
| C. | 50 cm |
| D. | \[5.76\times {{10}^{11}}\,newton/coulomb\] |
| Answer» D. \[5.76\times {{10}^{11}}\,newton/coulomb\] | |
| 21. |
The electric field near a conducting surface having a uniform surface charge density \[\sigma \] is given by [MP PMT 1994] |
| A. | \[\frac{\sigma }{{{\varepsilon }_{0}}}\] and is parallel to the surface |
| B. | \[\frac{2\sigma }{{{\varepsilon }_{0}}}\] and is parallel to the surface |
| C. | If assertion is true but reason is false. |
| D. | \[\frac{2\sigma }{{{\varepsilon }_{0}}}\] and is normal to the surface |
| Answer» D. \[\frac{2\sigma }{{{\varepsilon }_{0}}}\] and is normal to the surface | |
| 22. |
The number of electrons to be put on a spherical conductor of radius\[0.1\,m\] to produce an electric field of \[0.036N/C\] just above its surface is [MNR 1994; KCET (Engg.) 1999; MH CET (Med.) 2001] |
| A. | \[2.7\times {{10}^{5}}\] |
| B. | \[2.6\times {{10}^{5}}\] |
| C. | If assertion is true but reason is false. |
| D. | \[2.4\times {{10}^{5}}\] |
| Answer» D. \[2.4\times {{10}^{5}}\] | |
| 23. |
The intensity of electric field required to balance a proton of mass \[1.7\times {{10}^{-27}}kg\] and charge\[1.6\times {{10}^{-19}}C\] is nearly |
| A. | \[1\times {{10}^{-7}}\ V/m\] |
| B. | \[1\times {{10}^{-5}}\ V/m\] |
| C. | If assertion is true but reason is false. |
| D. | \[1\times {{10}^{5}}\ V/m\] |
| Answer» B. \[1\times {{10}^{-5}}\ V/m\] | |
| 24. |
A charge particle is free to move in an electric field. It will travel [IIT 1979] |
| A. | Always along a line of force |
| B. | Along a line of force, if its initial velocity is zero |
| C. | If assertion is true but reason is false. |
| D. | None of the above |
| Answer» C. If assertion is true but reason is false. | |
| 25. |
A hollow metallic sphere of radius R is given a charge Q. Then the potential at the centre is [Orissa JEE 2005] |
| A. | Zero |
| B. | \[\frac{1}{4\pi {{\varepsilon }_{0}}}.\frac{Q}{R}\] |
| C. | \[W=2{{r}^{2}}\pi T\] |
| D. | \[\frac{1}{4\pi {{\varepsilon }_{0}}}.\frac{Q}{2R}\] |
| Answer» C. \[W=2{{r}^{2}}\pi T\] | |
| 26. |
As per this diagram a point charge \[+q\] is placed at the origin \[O\]. Work done in taking another point charge \[-Q\] from the point \[A\] [co-ordinates \[(0,\,a)\]] to another point B [co-ordinates (a, 0)] along the straight path \[AB\] is [CBSE PMT 2005] |
| A. | Zero |
| B. | \[\left( \frac{-qQ}{4\pi {{\varepsilon }_{0}}}\frac{1}{{{a}^{2}}} \right)\,\sqrt{2}a\] |
| C. | Acute (Less than \[90{}^\circ \]) |
| D. | \[\left( \frac{qQ}{4\pi {{\varepsilon }_{0}}}\frac{1}{{{a}^{2}}} \right)\,\sqrt{2}a\] |
| Answer» B. \[\left( \frac{-qQ}{4\pi {{\varepsilon }_{0}}}\frac{1}{{{a}^{2}}} \right)\,\sqrt{2}a\] | |
| 27. |
A square of side ?a? has charge Q at its centre and charge ?q? at one of the corners. The work required to be done in moving the charge ?q? from the corner to the diagonally opposite corner is [UPSEAT 2004] |
| A. | Zero |
| B. | \[\frac{Qq}{4\pi {{\in }_{0}}a}\] |
| C. | |
| D. | \[\frac{Qq}{2\pi {{\in }_{0}}a}\] |
| Answer» B. \[\frac{Qq}{4\pi {{\in }_{0}}a}\] | |
| 28. |
Charges q, 2q, 3q and 4q are placed at the corners A, B, C and D of a square as shown in the following figure. The direction of electric field at the centre of the square is along [MP PMT 2004 |
| A. | AB |
| B. | CB |
| C. | \[qEa\sqrt{2}\] |
| D. | AC |
| Answer» C. \[qEa\sqrt{2}\] | |
| 29. |
A charge produces an electric field of 1 N/C at a point distant 0.1 m from it. The magnitude of charge is [RPET 2002] |
| A. | \[1.11\times {{10}^{-12}}\,C\] |
| B. | \[9.11\times {{10}^{-12}}\,C\] |
| C. | Inversely proportional to r |
| D. | None of these |
| Answer» B. \[9.11\times {{10}^{-12}}\,C\] | |
| 30. |
Two plates are at potentials ?10 V and +30 V. If the separation between the plates be 2 cm. The electric field between them is [Pb. PET 2000] |
| A. | 2000 V/m |
| B. | 1000 V/m |
| C. | A plane infinite sheet of charge |
| D. | 3000 V/m |
| Answer» B. 1000 V/m | |
| 31. |
Electric potential of earth is taken to be zero because earth is a good [AIIMS 1998; BHU 2002] |
| A. | Insulator |
| B. | Conductor |
| C. | \[R_{1}^{2}\ :\ R_{2}^{2}\] |
| D. | Dielectric |
| Answer» C. \[R_{1}^{2}\ :\ R_{2}^{2}\] | |
| 32. |
When a positive q charge is taken from lower potential to a higher potential point, then its potential energy will |
| A. | Decrease |
| B. | Increases |
| C. | \[8\times {{10}^{9}}\] N |
| D. | Become zero |
| Answer» C. \[8\times {{10}^{9}}\] N | |
| 33. |
In the electric field of a point charge \[q\], a certain charge is carried from point \[A\] to \[B\], \[C\], \[D\] and \[E\]. Then the work done [NCERT 1980] |
| A. | Is least along the path \[AB\] |
| B. | Is least along the path \[AD\] |
| C. | \[40MeV\] |
| D. | Is least along \[AE\] |
| Answer» D. Is least along \[AE\] | |
| 34. |
A point charge is kept at the centre of a metallic insulated spherical shell. Then [Orissa JEE 2003] |
| A. | Electric field out side the sphere is zero |
| B. | Electric field inside the sphere is zero |
| C. | \[2.04\times {{10}^{7}}N/C\] upwards |
| D. | Electric potential inside the sphere is zero |
| Answer» D. Electric potential inside the sphere is zero | |
| 35. |
A spherical conductor of radius 2m is charged to a potential of 120 V. It is now placed inside another hollow spherical conductor of radius 6m. Calculate the potential to which the bigger sphere would be raised [KCET 2001] |
| A. | 20 V |
| B. | 60 V |
| C. | \[262\,N/C\] |
| D. | 40 V |
| Answer» E. | |
| 36. |
The dimension of (1/2) \[{{\varepsilon }_{0}}{{E}^{2}}({{\varepsilon }_{0}}\]: permittivity of free space; \[E\]: electric field) is [IIT-JEE (Screening) 2000; KCET 2000] |
| A. | \[ML{{T}^{^{-1}}}\] |
| B. | \[M{{L}^{2}}{{T}^{-2}}\] |
| C. | \[qEy\] |
| D. | \[M{{L}^{2}}{{T}^{-1}}\] |
| Answer» D. \[M{{L}^{2}}{{T}^{-1}}\] | |
| 37. |
Three charges \[Q,\,+q\] and \[+q\] are placed at the vertices of a right-angled isosceles triangle as shown. The net electrostatic energy of the configuration is zero if Q is equal to [IIT-JEE (Screening) 2000] |
| A. | \[\frac{-q}{1+\sqrt{2}}\] |
| B. | \[\frac{-2q}{2+\sqrt{2}}\] |
| C. | \[\frac{9}{25}J\] |
| D. | \[+q\] |
| Answer» C. \[\frac{9}{25}J\] | |
| 38. |
Two charges \[+5\mu C\] and \[+10\mu C\] are placed 20 cm apart. The net electric field at the mid-Point between the two charges is [KCET (Med.) 2000] |
| A. | \[4.5\times {{10}^{6}}\] N/C directed towards \[+5\mu C\] |
| B. | \[4.5\times {{10}^{6}}\] N/C directed towards \[+10\mu C\] |
| C. | Surface charge density on the \[15\,cm\] sphere will be greater than that on the \[20\,cm\] sphere |
| D. | \[13.5\times {{10}^{6}}\] N/C directed towards \[+10\mu C\] |
| Answer» B. \[4.5\times {{10}^{6}}\] N/C directed towards \[+10\mu C\] | |
| 39. |
Which of the following is deflected by electric field [CPMT 2000] |
| A. | X-rays |
| B. | \[\gamma \]-rays |
| C. | \[M\] |
| D. | \[\alpha \]-particles |
| Answer» E. | |
| 40. |
The distance between the two charges \[+q\] and \[-q\] of a dipole is \[r\]. On the axial line at a distance \[d\] from the centre of dipole, the intensity is proportional to [CPMT 1977] |
| A. | \[\frac{q}{{{d}^{2}}}\] |
| B. | \[\frac{qr}{{{d}^{2}}}\] |
| C. | Return back along its path without touching the disc |
| D. | \[\frac{qr}{{{d}^{3}}}\] |
| Answer» E. | |
| 41. |
Two charges \[+3.2\times {{10}^{-19}}C\] and \[-3.2\times {{10}^{-9}}C\] kept 2.4 Å apart forms a dipole. If it is kept in uniform electric field of intensity \[4\times {{10}^{5}}volt/m\] then what will be its electrical energy in equilibrium [MP PMT 2003] |
| A. | \[+3\times {{10}^{-23}}J\] |
| B. | \[-3\times {{10}^{-23}}J\] |
| C. | \[1.44\times {{10}^{11}}\,newton/coulomb\] |
| D. | \[-2\times {{10}^{-23}}J\] |
| Answer» C. \[1.44\times {{10}^{11}}\,newton/coulomb\] | |
| 42. |
The electric potential at a point on the axis of an electric dipole depends on the distance \[r\] of the point from the dipole as [CPMT 1982; UPSEAT 2001 MP PMT 1996, 2002; MP PET 2001, 05] |
| A. | \[\propto \frac{1}{r}\] |
| B. | \[\propto \frac{1}{{{r}^{2}}}\] |
| C. | \[1:4\] |
| D. | \[\propto \frac{1}{{{r}^{3}}}\] |
| Answer» C. \[1:4\] | |
| 43. |
Intensity of an electric field E due to a dipole, depends on distance r as [Pb. PMT 2004] |
| A. | \[E\propto \frac{1}{{{r}^{4}}}\] |
| B. | \[E\propto \frac{1}{{{r}^{3}}}\] |
| C. | \[\frac{\sigma }{{{\varepsilon }_{0}}}\] and is normal to the surface |
| D. | \[E\propto \frac{1}{r}\] |
| Answer» C. \[\frac{\sigma }{{{\varepsilon }_{0}}}\] and is normal to the surface | |
| 44. |
Electric potential at an equatorial point of a small dipole with dipole moment \[P\](r, distance from the dipole) is [MP PMT 2001] |
| A. | Zero |
| B. | \[\frac{P}{4\pi {{\varepsilon }_{0}}{{r}^{2}}}\] |
| C. | \[2.5\times {{10}^{5}}\] |
| D. | \[\frac{2P}{4\pi {{\varepsilon }_{0}}{{r}^{3}}}\] |
| Answer» B. \[\frac{P}{4\pi {{\varepsilon }_{0}}{{r}^{2}}}\] | |
| 45. |
The electric field at a point on equatorial line of a dipole and direction of the dipole moment [MP PET 1995] |
| A. | Will be parallel |
| B. | Will be in opposite direction |
| C. | \[1\times {{10}^{7}}\ V/m\] |
| D. | Are not related |
| Answer» C. \[1\times {{10}^{7}}\ V/m\] | |
| 46. |
Two charges\[+3.2\times {{10}^{-19}}\] and \[-3.2\times {{10}^{-19}}C\] placed at \[2.4{AA}\] apart form an electric dipole. It is placed in a uniform electric field of intensity \[4\times {{10}^{5}}\,volt/m\]. The electric dipole moment is |
| A. | \[15.36\times {{10}^{-29}}\ coulomb\times m\] |
| B. | \[15.36\times {{10}^{-19}}\ coulomb\times m\] |
| C. | Along a line of force, if it has some initial velocity in the direction of an acute angle with the line of force |
| D. | \[7.68\times {{10}^{-19}}\ coulomb\times m\] |
| Answer» D. \[7.68\times {{10}^{-19}}\ coulomb\times m\] | |
| 47. |
Two identical thin rings each of radius R meters are coaxially placed at a distance R meters apart. If Q1 coulomb and Q2 coulomb are respectively the charges uniformly spread on the two rings, the work done in moving a charge qfrom the centre of one ring to that of other is [MP PMT 1999; AMU (Engg.) 1999] |
| A. | Zero |
| B. | \[\frac{q({{Q}_{1}}-{{Q}_{2}})(\sqrt{2}-1)}{\sqrt{2}.4\pi {{\varepsilon }_{0}}R}\] |
| C. | \[\frac{1}{4\pi {{\varepsilon }_{0}}}.\frac{2Q}{R}\] |
| D. | \[\frac{q({{Q}_{1}}+{{Q}_{2}})(\sqrt{2}+1)}{\sqrt{2}.4\pi {{\varepsilon }_{0}}R}\] |
| Answer» C. \[\frac{1}{4\pi {{\varepsilon }_{0}}}.\frac{2Q}{R}\] | |
| 48. |
The plates of a capacitor are charged to a potential difference of 320 volts and are then connected across a resistor. The potential difference across the capacitor decays exponentially with time. After 1 second the potential difference between the plates of the capacitor is 240 volts, then after 2 and 3 seconds the potential difference between the plates will be [MP PET 1996] |
| A. | 200 and 180 V |
| B. | 180 and 135 V |
| C. | \[\left( \frac{qQ}{4\pi {{\varepsilon }_{0}}}\frac{1}{{{a}^{2}}} \right)\,\frac{a}{\sqrt{2}}\] |
| D. | 140 and 20 V |
| Answer» C. \[\left( \frac{qQ}{4\pi {{\varepsilon }_{0}}}\frac{1}{{{a}^{2}}} \right)\,\frac{a}{\sqrt{2}}\] | |
| 49. |
Four metallic plates each with a surface area of one side A are placed at a distance d from each other. The plates are connected as shown in the circuit diagram. Then the capacitance of the system between \[a\] and \[b\] is |
| A. | \[\frac{3{{\varepsilon }_{0}}A}{d}\] |
| B. | \[\frac{2{{\varepsilon }_{0}}A}{d}\] |
| C. | \[\frac{Qq\sqrt{2}}{4\pi {{\in }_{0}}a}\] |
| D. | \[\frac{3{{\varepsilon }_{0}}A}{2d}\] |
| Answer» E. | |
| 50. |
Two condensers of capacities \[2C\] and C are joined in parallel and charged upto potential V. The battery is removed and the condenser of capacity C is filled completely with a medium of dielectric constant K. The p.d. across the capacitors will now be [IIT 1988] |
| A. | \[\frac{3V}{K+2}\] |
| B. | \[\frac{3V}{K}\] |
| C. | BD |
| D. | \[\frac{V}{K}\] |
| Answer» B. \[\frac{3V}{K}\] | |