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MCQOPTIONS
This section includes 12583 Mcqs, each offering curated multiple-choice questions to sharpen your Joint Entrance Exam - Main (JEE Main) knowledge and support exam preparation. Choose a topic below to get started.
| 7351. |
Figures below show regular hexagons, with charges at the vertices. In which of the following cases the electric field at the centre is not zero [AMU 2000] |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| 7352. |
In the given figure distance of the point from A where the electric field is zero is [RPMT 2000] |
| A. | 20 cm |
| B. | 10 cm |
| C. | 33 cm |
| D. | None of these |
| Answer» D. None of these | |
| 7353. |
Two electric charges \[12\mu C\] and \[-6\mu C\] are placed 20 cm apart in air. There will be a point P on the line joining these charges and outside the region between them, at which the electric potential is zero. The distance of P from \[-6\mu C\] charge is [EAMCET 2000] |
| A. | 0.10 m |
| B. | 0.15 m |
| C. | 0.20 m |
| D. | 0.25 m |
| Answer» D. 0.25 m | |
| 7354. |
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. | \[-2q\] |
| D. | \[+q\] |
| Answer» C. \[-2q\] | |
| 7355. |
A charged particle of mass \[5\times {{10}^{-5}}kg\] is held stationary in space by placing it in an electric field of strength \[{{10}^{7}}N{{C}^{-1}}\] directed vertically downwards. The charge on the particle is [EAMCET 2000] |
| A. | \[-20\times {{10}^{-5}}\mu C\] |
| B. | \[-5\times {{10}^{-5}}\mu C\] |
| C. | \[5\times {{10}^{-5}}\mu C\] |
| D. | \[20\times {{10}^{-5}}\mu C\] |
| Answer» C. \[5\times {{10}^{-5}}\mu C\] | |
| 7356. |
Consider the points lying on a straight line joining two fixed opposite charges. Between the charges there is [Roorkee 2000] |
| A. | No point where electric field is zero |
| B. | Only one point where electric field is zero |
| C. | No point where potential is zero |
| D. | Only one point where potential is zero |
| Answer» B. Only one point where electric field is zero | |
| 7357. |
As shown in the figure, charges \[+q\] and \[-q\] are placed at the vertices \[B\] and \[C\] of an isosceles triangle. The potential at the vertex A is [MP PET 2000] |
| A. | \[\frac{1}{4\pi {{\varepsilon }_{0}}}.\frac{2q}{\sqrt{{{a}^{2}}+{{b}^{2}}}}\] |
| B. | Zero |
| C. | \[\frac{1}{4\pi {{\varepsilon }_{0}}}.\frac{q}{\sqrt{{{a}^{2}}+{{b}^{2}}}}\] |
| D. | \[\frac{1}{4\pi {{\varepsilon }_{0}}}.\frac{(-q)}{\sqrt{{{a}^{2}}+{{b}^{2}}}}\] |
| Answer» C. \[\frac{1}{4\pi {{\varepsilon }_{0}}}.\frac{q}{\sqrt{{{a}^{2}}+{{b}^{2}}}}\] | |
| 7358. |
Which of the following is deflected by electric field [CPMT 2000] |
| A. | X-rays |
| B. | \[\gamma \]-rays |
| C. | Neutrons |
| D. | \[\alpha \]-particles |
| Answer» E. | |
| 7359. |
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. | \[13.5\times {{10}^{6}}\] N/C directed towards \[+5\mu C\] |
| D. | \[13.5\times {{10}^{6}}\] N/C directed towards \[+10\mu C\] |
| Answer» B. \[4.5\times {{10}^{6}}\] N/C directed towards \[+10\mu C\] | |
| 7360. |
Electric lines of force about negative point charge are [MP PMT 1987] |
| A. | Circular, anticlockwise |
| B. | Circular, clockwise |
| C. | Radial, inward |
| D. | Radial, outward |
| Answer» D. Radial, outward | |
| 7361. |
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 [IIT 1987; CBSE PMT 1995; Bihar MEE 1995; CPMT 1999; MP PET 1999; MP PMT 1999, 2000; RPET 1999; KCET 2001; AIEEE 2002; AFMC 2002; Kerala PMT 2004; J & K CET 2004] |
| A. | \[-\frac{Q}{2}\] |
| B. | \[-\frac{Q}{4}\] |
| C. | \[+\frac{Q}{4}\] |
| D. | \[+\frac{Q}{2}\] |
| Answer» C. \[+\frac{Q}{4}\] | |
| 7362. |
An electron and a proton are at a distance of \[1{AA}\]. The moment of this dipole will be (C ´ m) [CPMT 1984] |
| A. | \[1.6\times {{10}^{19}}\] |
| B. | \[1.6\times {{10}^{-29}}\] |
| C. | \[3.2\times {{10}^{19}}\] |
| D. | \[3.2\times {{10}^{29}}\] |
| Answer» C. \[3.2\times {{10}^{19}}\] | |
| 7363. |
An electric dipole consisting of two opposite charges of \[2\times {{10}^{-6}}C\] each separated by a distance of \[3\,cm\] is placed in an electric field of \[2\times {{10}^{5}}\] N/C. The maximum torque on the dipole will be [MP PMT 1987] |
| A. | \[12\times {{10}^{-1}}N\,m\] |
| B. | \[12\times {{10}^{-3}}N\,m\] |
| C. | \[24\times {{10}^{-1}}N\,m\] |
| D. | \[24\times {{10}^{-3}}N\,m\] |
| Answer» C. \[24\times {{10}^{-1}}N\,m\] | |
| 7364. |
An electric dipole is kept in non-uniform electric field. It experiences [AIIMS 2003; DCE 2001] |
| A. | A force and a torque |
| B. | A force but not a torque |
| C. | A torque but not a force |
| D. | Neither a force nor a torque |
| Answer» B. A force but not a torque | |
| 7365. |
An electric dipole of moment \[p\] is placed in the position of stable equilibrium in uniform electric field of intensity \[E\]. It is rotated through an angle \[\theta \] from the initial position. The potential energy of electric dipole in the final position is [MP PET 1993] |
| A. | \[pE\cos \theta \] |
| B. | \[pE\sin \theta \] |
| C. | \[pE(1-\cos \theta )\] |
| D. | \[-pE\cos \theta \] |
| Answer» E. | |
| 7366. |
The electric field due to an electric dipole at a distance r from its centre in axial position is E. If the dipole is rotated through an angle of \[\text{9}0{}^\circ \]about its perpendicular axis, the electric field at the same point will be [J & K CET 2005] |
| A. | E |
| B. | E / 4 |
| C. | E / 2 |
| D. | 2E |
| Answer» D. 2E | |
| 7367. |
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. | \[-6\times {{10}^{-23}}J\] |
| D. | \[-2\times {{10}^{-23}}J\] |
| Answer» C. \[-6\times {{10}^{-23}}J\] | |
| 7368. |
What is the angle between the electric dipole moment and the electric field strength due to it on the equatorial line [AFMC 2005] |
| A. | \[{{0}^{\text{o}}}\] |
| B. | \[\text{9}0{}^\circ \] |
| C. | \[\text{18}{{0}^{\text{o}}}\] |
| D. | None of these |
| Answer» D. None of these | |
| 7369. |
When an electric dipole \[\overrightarrow{P}\] is placed in a uniform electric field \[\overrightarrow{E}\] then at what angle between \[\overrightarrow{P}\] and \[\overrightarrow{E}\] the value of torque will be maximum [MP PET 2002] |
| A. | \[{{90}^{o}}\] |
| B. | \[{{0}^{o}}\] |
| C. | \[{{180}^{o}}\] |
| D. | \[{{45}^{o}}\] |
| Answer» B. \[{{0}^{o}}\] | |
| 7370. |
Two electric dipoles of moment P and 64 P are placed in opposite direction on a line at a distance of 25 cm. The electric field will be zero at point between the dipoles whose distance from the dipole of moment P is [MP PET 2003] |
| A. | 5 cm |
| B. | \[\frac{25}{9}\]cm |
| C. | 10 cm |
| D. | \[\frac{4}{13}\] cm |
| Answer» B. \[\frac{25}{9}\]cm | |
| 7371. |
A region surrounding a stationary electric dipoles has [MP PET 1994] |
| A. | Magnetic field only |
| B. | Electric field only |
| C. | Both electric and magnetic fields |
| D. | No electric and magnetic fields |
| Answer» C. Both electric and magnetic fields | |
| 7372. |
An electric dipole of moment \[\overrightarrow{p}\] placed in a uniform electric field \[\overrightarrow{E}\] has minimum potential energy when the angle between \[\overrightarrow{p}\] and \[\overrightarrow{E}\] is [UPSEAT 2004] |
| A. | Zero |
| B. | \[\frac{\pi }{2}\] |
| C. | \[\pi \] |
| D. | \[\frac{3\pi }{2}\] |
| Answer» B. \[\frac{\pi }{2}\] | |
| 7373. |
A molecule with a dipole moment p is placed in an electric field of strength E. Initially the dipole is aligned parallel to the field. If the dipole is to be rotated to be anti-parallel to the field, the work required to be done by an external agency is [UPSEAT 2004] |
| A. | ? 2pE |
| B. | ? pE |
| C. | pE |
| D. | 2pE |
| Answer» E. | |
| 7374. |
For a dipole \[q=2\times {{10}^{-6}}\,C\] and \[d=0.01\,m\]. Calculate the maximum torque for this dipole if \[E=5\times {{10}^{5}}\,N/C\] [RPMT 2003] |
| A. | \[1\times {{10}^{-3}}N{{m}^{-1}}\] |
| B. | \[10\times {{10}^{-3}}N{{m}^{-1}}\] |
| C. | \[10\times {{10}^{-3}}Nm\] |
| D. | \[1\times {{10}^{2}}N{{m}^{2}}\] |
| Answer» D. \[1\times {{10}^{2}}N{{m}^{2}}\] | |
| 7375. |
The ratio of electric fields on the axis and at equator of an electric dipole will be [RPMT 2002] |
| A. | 1 : 1 |
| B. | 2 : 1 |
| C. | 4 : 1 |
| D. | None of these |
| Answer» C. 4 : 1 | |
| 7376. |
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. | \[\propto r\] |
| D. | \[\propto \frac{1}{{{r}^{3}}}\] |
| Answer» C. \[\propto r\] | |
| 7377. |
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. | \[E\propto \frac{1}{{{r}^{2}}}\] |
| D. | \[E\propto \frac{1}{r}\] |
| Answer» C. \[E\propto \frac{1}{{{r}^{2}}}\] | |
| 7378. |
The value of electric potential at any point due to any electric dipole is [MP PMT 2004] |
| A. | \[k.\frac{\overrightarrow{p}\times \overrightarrow{r}}{{{r}^{2}}}\] |
| B. | \[k.\frac{\overrightarrow{p}\times \overrightarrow{r}}{{{r}^{3}}}\] |
| C. | \[k.\frac{\overrightarrow{p}\cdot \overrightarrow{r}}{{{r}^{2}}}\] |
| D. | \[k.\frac{\overrightarrow{p}\cdot \overrightarrow{r}}{{{r}^{3}}}\] |
| Answer» E. | |
| 7379. |
An electric dipole has the magnitude of its charge as q and its dipole moment is p. It is placed in a uniform electric field E. If its dipole moment is along the direction of the field, the force on it and its potential energy are respectively [CBSE PMT 2004] |
| A. | \[2q\cdot E\] and minimum |
| B. | \[q\cdot E\] and \[p\cdot E\] |
| C. | Zero and minimum |
| D. | \[q\cdot E\] and maximum |
| Answer» D. \[q\cdot E\] and maximum | |
| 7380. |
The potential at a point due to an electric dipole will be maximum and minimum when the angles between the axis of the dipole and the line joining the point to the dipole are respectively [MP PMT 2002] |
| A. | \[{{90}^{o}}\] and \[{{180}^{o}}\] |
| B. | \[{{0}^{o}}\] and \[{{90}^{o}}\] |
| C. | \[{{90}^{o}}\] and \[{{0}^{o}}\] |
| D. | \[{{0}^{o}}\] and \[{{180}^{o}}\] |
| Answer» E. | |
| 7381. |
The distance between \[{{H}^{+}}\] and \[C{{l}^{-}}\] ions in HCl molecule is 1.28 Å. What will be the potential due to this dipole at a distance of 12 Å on the axis of dipole [MP PMT 2002] |
| A. | 0.13 V |
| B. | 1.3 V |
| C. | 13 V |
| D. | 130 V |
| Answer» B. 1.3 V | |
| 7382. |
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. | \[\frac{P}{4\pi {{\varepsilon }_{0}}{{r}^{3}}}\] |
| D. | \[\frac{2P}{4\pi {{\varepsilon }_{0}}{{r}^{3}}}\] |
| Answer» B. \[\frac{P}{4\pi {{\varepsilon }_{0}}{{r}^{2}}}\] | |
| 7383. |
The electric intensity due to a dipole of length 10 cm and having a charge of \[500\mu C\], at a point on the axis at a distance 20 cm from one of the charges in air, is [CBSE PMT 2001] |
| A. | \[6.25\times {{10}^{7}}\] N/C |
| B. | \[9.28\times {{10}^{7}}\] N/C |
| C. | \[13.1\times {{11}^{11}}\] N/C |
| D. | \[20.5\times {{10}^{7}}\] N/C |
| Answer» B. \[9.28\times {{10}^{7}}\] N/C | |
| 7384. |
An electric dipole in a uniform electric field experiences (When it is placed at an angle \[\theta \] with the field) [RPET 2000] |
| A. | Force and torque both |
| B. | Force but no torque |
| C. | Torque but no force |
| D. | No force and no torque |
| Answer» D. No force and no torque | |
| 7385. |
If the magnitude of intensity of electric field at a distance \[x\] on axial line and at a distance \[y\] on equatorial line on a given dipole are equal, then \[x:y\] is [EAMCET 1994] |
| A. | \[1:1\] |
| B. | \[1:\sqrt{2}\] |
| C. | \[1:2\] |
| D. | \[\sqrt[3]{2}:1\] |
| Answer» E. | |
| 7386. |
A point \[Q\] lies on the perpendicular bisector of an electrical 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 field at \[Q\] is proportional to [CBSE PMT 1998; JIPMER 2001, 02] |
| A. | \[{{p}^{-1}}\] and \[{{r}^{-2}}\] |
| B. | \[p\] and \[{{r}^{-2}}\] |
| C. | \[{{p}^{-1}}\] and \[{{r}^{-2}}\] |
| D. | \[p\] and \[{{r}^{-3}}\] |
| Answer» E. | |
| 7387. |
An electric dipole is placed in an electric field generated by a point charge [MP PMT 1999] |
| A. | The net electric force on the dipole must be zero |
| B. | The net electric force on the dipole may be zero |
| C. | The torque on the dipole due to the field must be zero |
| D. | The torque on the dipole due to the field may be zero |
| Answer» E. | |
| 7388. |
If \[{{E}_{a}}\] be the electric field strength of a short dipole at a point on its axial line and \[{{E}_{e}}\] that on the equatorial line at the same distance, then [MP PET 1999; J & K CET 2004] |
| A. | \[{{E}_{e}}=2{{E}_{a}}\] |
| B. | \[{{E}_{a}}=2{{E}_{e}}\] |
| C. | \[{{E}_{a}}={{E}_{e}}\] |
| D. | None of the above |
| Answer» C. \[{{E}_{a}}={{E}_{e}}\] | |
| 7389. |
Two opposite and equal charges \[4\times {{10}^{-8}}coulomb\] when placed \[2\times {{10}^{-2}}cm\] away, form a dipole. If this dipole is placed in an external electric field \[4\times {{10}^{8}}newton/coulomb\], the value of maximum torque and the work done in rotating it through \[180{}^\circ \] will be [MP PET 1996] |
| A. | \[64\times {{10}^{-4}}Nm\] and \[64\times {{10}^{-4}}J\] |
| B. | \[32\times {{10}^{-4}}\]Nm and \[32\times {{10}^{-4}}J\] |
| C. | \[64\times {{10}^{-4}}Nm\] and \[32\times {{10}^{-4}}J\] |
| D. | \[32\times {{10}^{-4}}Nm\] and \[64\times {{10}^{-4}}J\] |
| Answer» E. | |
| 7390. |
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. | Will be perpendicular |
| D. | Are not related |
| Answer» C. Will be perpendicular | |
| 7391. |
The torque acting on a dipole of moment \[\overrightarrow{P}\] in an electric field \[\overrightarrow{E}\] is [MP PMT 1994; CPMT 2001] |
| A. | \[\overrightarrow{P}\cdot \overrightarrow{E}\] |
| B. | \[\overrightarrow{P}\times \overrightarrow{E}\] |
| C. | Zero |
| D. | \[\overrightarrow{E}\times \overrightarrow{P}\] |
| Answer» C. Zero | |
| 7392. |
Electric charges \[q,\,q,\,-2q\] are placed at the corners of an equilateral triangle \[ABC\] of side \[l\]. The magnitude of electric dipole moment of the system is [MP PMT 1994] |
| A. | \[ql\] |
| B. | \[2ql\] |
| C. | \[\sqrt{3}ql\] |
| D. | \[4ql\] |
| Answer» D. \[4ql\] | |
| 7393. |
An electric dipole is placed along the \[x-\]axis at the origin \[O\]. A point \[P\] is at a distance of \[20\,cm\] from this origin such that \[OP\] makes an angle \[\frac{\pi }{3}\] with the x-axis. If the electric field at \[P\] makes an angle \[\theta \] with the x-axis, the value of \[\theta \] would be [MP PMT 1997] |
| A. | \[\frac{\pi }{3}\] |
| B. | \[\frac{\pi }{3}+{{\tan }^{-1}}\left( \frac{\sqrt{3}}{2} \right)\] |
| C. | \[\frac{2\pi }{3}\] |
| D. | \[{{\tan }^{-1}}\left( \frac{\sqrt{3}}{2} \right)\] |
| Answer» C. \[\frac{2\pi }{3}\] | |
| 7394. |
An electric dipole of moment \[p\]is placed at the origin along the \[x\]-axis. The electric field at a point \[P\], whose position vector makes an angle\[\theta \]with the \[x\]-axis, will make an angle ..... with the \[x\]-axis, where \[\tan \alpha =\frac{1}{2}\tan \theta \] [MP PMT 1994] |
| A. | \[\alpha \] |
| B. | \[\theta \] |
| C. | \[\theta +\alpha \] |
| D. | \[\theta +2\alpha \] |
| Answer» D. \[\theta +2\alpha \] | |
| 7395. |
The electric field due to a dipole at a distance\[r\] on its axis is [MP PMT 1993; RPET 2001; MP PET/PMT 2002; BCECE 2003] |
| A. | Directly proportional to \[{{r}^{3}}\] |
| B. | Inversely proportional to \[{{r}^{3}}\] |
| C. | Directly proportional to \[{{r}^{2}}\] |
| D. | Inversely proportional to \[{{r}^{2}}\] |
| Answer» C. Directly proportional to \[{{r}^{2}}\] | |
| 7396. |
An electric dipole when placed in a uniform electric field \[E\] will have minimum potential energy, if the positive direction of dipole moment makes the following angle with \[E\] [CPMT 1981; MP PMT 1987] |
| A. | \[\pi \] |
| B. | \[\pi /2\] |
| C. | Zero |
| D. | \[3\pi /2\] |
| Answer» D. \[3\pi /2\] | |
| 7397. |
The resistance of an incandescent lamp is [KCET 2002] |
| A. | Greater when switched off |
| B. | Smaller when switched on |
| C. | Greater when switched on |
| D. | The same whether it is switched off or switched on |
| Answer» D. The same whether it is switched off or switched on | |
| 7398. |
The resistance of a 5 cm long wire is 10 W. It is uniformly stretched so that its length becomes 20 cm. The resistance of the wire is [MH CET 2002] |
| A. | 160 W |
| B. | 80 W |
| C. | 40 W |
| D. | 20 W |
| Answer» B. 80 W | |
| 7399. |
At room temperature, copper has free electron density of \[8.4\times {{10}^{28}}\] per \[{{m}^{3}}\]. The copper conductor has a cross-section of \[{{10}^{6}}{{m}^{2}}\]and carries a current of 5.4 A. The electron drift velocity in copper is [UPSEAT 2002] |
| A. | 400 m/s |
| B. | 0.4 m/s |
| C. | 0.4 m/s |
| D. | 72 m/s |
| Answer» D. 72 m/s | |
| 7400. |
There is a current of 40 ampere in a wire of \[{{10}^{-6}}\,{{m}^{2}}\] area of cross-section. If the number of free electron per \[{{m}^{3}}\] is \[{{10}^{29}}\], then the drift velocity will be [Pb. PMT 2001] |
| A. | \[1.25\text{ }\times ~{{10}^{3}}m/s\] |
| B. | \[2.50\text{ }\times ~{{10}^{-3}}m/s\] |
| C. | \[25.0\text{ }\times ~{{10}^{-3}}m/s\] |
| D. | \[250\text{ }\times ~{{10}^{-3}}m/s\] |
| Answer» C. \[25.0\text{ }\times ~{{10}^{-3}}m/s\] | |