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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 401. |
There are four concentric shells A,B, C and D of radii `a,2a,3a` and `4a` respectively. Shells B and D are given charges `+q` and `-q` respectively. Shell C is now earthed. The potential difference `V_A-V_C` is `k=(1/(4piepsilon_0))` |
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Answer» Correct Answer - 6 |
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| 402. |
Three concentric metallic spherical shells `A,B` and `C` of radii `a,b` and `c(a lt blt c)` have surface charge densities `-sigma ,+sigma `and `-sigma` respectively ,the potential of shell `A` isA. `sigma/epsi_(0) [(b^(2)-c^(2))/b+a]`B. `sigma/epsi_(0) [(b^(2)-c^(2))/c+a]`C. `sigma/epsi_(0) [(a^(2)-b^(2))/a+c]`D. `sigma/epsi_(0) [(a^(2)-b^(2))/b+c]` |
| Answer» Correct Answer - D | |
| 403. |
A spherical charged conductor has surface charge density `sigma`.The intensity of electric field and potential on its surface are `E` and `V` .Now radius of sphere is halved keeping the charge density as constant .The new electric field on the surface and potential at the centre of the sphere areA. 2E, 2 VB. 4E, 2 VC. 4E, 4 VD. 2E, 4 V |
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Answer» Correct Answer - B |
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| 404. |
The Gaussian surface for calculating the electric field due to a charge distribution isA. any surface near the charge distributionB. always a spherical surfaceC. a symmetrical closed surface containing the charge distribution, at very point of which electric field has a single fixed valueD. None of the given options |
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Answer» Correct Answer - C |
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| 405. |
The energy stored in a charged capacitor of capa city 25 µF is 4J. Find the charge on its plate. |
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Answer» Data: C = 25 pF = 25 × 10-12 F, U = 4 J U = \(\cfrac12\)\(\cfrac{Q^2}C\) ∴ The charge, Q = \(\sqrt{2UC}\) = \(\sqrt{2\times4\times25\times10^{-12}}\) = 1.414 x 10-5 C (= 14.14 µC) |
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| 406. |
The plates of a parallel plate capacitor are charged up to `100 v`. Now, after removing the battery, a `2 mm` thick plate is inserted between the plates Then, to maintain the same potential deffernce, the distance betweem the capacitor plates is increase by `1.6 mm`. The dielectric canstant of the plate is .A. 6B. 8C. 5D. 4 |
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Answer» Correct Answer - C |
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| 407. |
Two capacitors of capacitances `3muF and 5muF` respectively are connected in parallel and this combination is connected in series with a third capacitor of capacitance `2muF`. A potential difference of 100 V is applied across the entire combination. The charge and the potential difference across the third capacitor isA. `100muC, 40 V`B. `100muC, 80 V`C. `160muC, 40 V`D. `160muC, 80 V` |
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Answer» Correct Answer - D `C_(P)=C_(1)+C_(2)=3+5=8muF` `C_(S) = (C_(p)*C_(3))/(C_(p)+C_(3))=(8xx2)/(8+2)=1.6muF` `Q=C_(S)*V=1.6xx100=160muC` `V_(3)=(C_(p)/(C_(p)+C_(3)))V=(8/(8+2))100=80V.` |
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| 408. |
Two capacitors of capacity `6 muF` and 3 muF` are charge `100 V` and `50 V` separately and connected as shown in Now all the three switches `S_(1),S_(2)`, and `S_(3)` are closed. Which plates form an isolated system?A. plate 1 and plate 4 separatelyB. plate 2 and plate 3 separatelyC. plates 1 and 4 jointlyD. plates 2 and 3 jointly |
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Answer» Correct Answer - D |
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| 409. |
Three capacitors `2muF`, `3muF` and `5muF` can withstand voltages to `3V`,`2V` and `1V` respectively. Their series combination can withstand a maximum voltage equal toA. 5 VB. 31/6 VC. 26/5 VD. 6 V |
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Answer» Correct Answer - B |
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| 410. |
Two capacitors of `2muF` and `3muF` are charged to `150 V` and `120 V`, respectively. The plates of capacitor are connected as shown in the figure. An uncharged capacitor of capacity `1.5muF` falls to the free end of the wire. Then A. charge on the `1.5 muF` capacitor is `20 muC`B. charge on the `2muF` capacitor is `280 muC`C. positive charge flows through A from right to leftD. positive charge flows through A from left to right |
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Answer» Correct Answer - A::B::C |
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| 411. |
Three concentric spherical shells have radii `a, b` and `c(a lt b lt c)` and have surface charge densities `sigma, -sigam` and `sigma` respectively. If `V_(A), V_(B)` and `V_(C)` denote the potentials of the three shells, then for `c = q + b`, we haveA. `V_(C) = V_(A) ne V_(B)`B. `V_(C) = V_(B) ne V_(A)`C. `V_(C) ne V_(B) ne V_(A)`D. `V_(C) = V_(B) = V_(A)` |
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Answer» Correct Answer - D |
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| 412. |
Three concentric spherical shells have radii `a, b` and `c(a lt b lt c)` and have surface charge densities `sigma, -sigam` and `sigma` respectively. If `V_(A), V_(B)` and `V_(C)` denote the potentials of the three shells, then for `c = q + b`, we haveA. `V_(C ) = V_(A) != V_(B)`B. `V_(C ) = V_(B) != V_(A)`C. `V_(C ) != V_(A) != V_(B)`D. `V_(C) = V_(B) = V_(A)` |
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Answer» Correct Answer - 1 If `c = a + b` `V_(A) = V_(C) != V_(B)` |
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| 413. |
A parallel plate air capacitor is charged to a potential difference of `V` volts. After disconnecting the charging battery the distance between the plates of the capacitor is increased using an isulating handle. As a result the potential difference between the platesA. decreasesB. does not changeC. becomes zeroD. increases |
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Answer» Correct Answer - D |
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| 414. |
A square surface of side `L` metre in the plane of the paper is placed in a uniform electric field `E ("volt"//m)` acting along the same place at an anlge `theta` with the horizontal side of the square as shown in figure. The electric flux linked to the surface in uint of `V-m` is |
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Answer» Correct Answer - D |
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| 415. |
Under the influence of the Coulomb field of charge `+Q`, a charge `-q` is moving around it in an elliptical orbit. Find out the correct statement(s).A. The angular momentum of the charge -q is constant.B. The linear momentum of the charge -q is constant.C. The angular velocity of the charge -q is constant.D. The linear speed of the charge -q is constant. |
| Answer» Correct Answer - A | |
| 416. |
Three concentric metallic spherical shells of radii R, 2R, 3R are given charges `Q_(1) Q_(2) Q_(3)`, respectively. It is found that the surface charge densities on the outer surface of the shells are equal. Then, the ratio of the charges given to the shells `Q_(1) : Q_(2) : Q_(3)` isA. `1 : 2 : 3`B. `1 : 3 : 5`C. `1 : 4 : 9`D. `1 : 8 : 18` |
| Answer» Correct Answer - B | |
| 417. |
Two identical charged spheres of material density `rho`, suspended from the same point by inextensible strings of equal length make an angle `theta` between the string. When suspended in a liquid of density `sigma` the angle `theta` remains the same. The dielectric constant K of the liquid isA. `(rho)/(rho - sigma)`B. `(rho - sigma)/(rho)`C. `(rho)/(rho + sigma)`D. `(rho + sigma)/(rho)` |
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Answer» Correct Answer - A |
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| 418. |
Two small balls having equal positive charge Q (coulumb) on each suspended by two insulating strings of equal length L (metre) from a hook fixed to a stand. The whole set-up is taken in a satellite into space where there is no gravity (state of weightlessness). Then tension (newtons) in each string is:A. `(Q^(2))/(4piin_(0)L^(2))`B. `(Q^(2))/(8piin_(0) L^(2))`C. `(Q^(2))/(12 pi in_(0)L^(2))`D. `(Q^(2))/(16 pi in_(0)L^(2))` |
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Answer» Correct Answer - D Since, there is no gravity in a space statellite, so electrostatic repultion force (only) acts on two charges which is balanced by tension in strings. |
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| 419. |
Two particles `X` and `Y` of equal mass and with unequal positive charges, are free to move and are initially far away from each other. With `Y` at rest,` X` begins to move towards it with initial velocity `u`. After a long time, finallyA. `X` will stop `Y` will move with velocity `u`B. `X` and `Y` will both move with velocities `u//2` eachC. `X` will stop `Y` will move with velocity `ltu`D. both will move with velocities `ltu//2` |
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Answer» Correct Answer - A |
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| 420. |
Two positively charged particles ` X` and `Y` are initially far away from each other and at rest , `X` begins to move towards `Y` with some initial velocity. The total momentum and energy of the system are `p` and `E`.A. If `Y` is fixed both `p` and `E` are conserved.B. If `Y` is fixed `E` is conserved but not `p`C. If both are free to move `p` is conserved but not `E`D. If both are free, `E` conserved, but not `p`. |
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Answer» Correct Answer - B |
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| 421. |
A circular ring of radius R with uniform positive charge density `lambda` per unit length is located in the y z plane with its center at the origin O. A particle of mass m and positive charge q is projected from that point `p( - sqrt(3) R, 0,0)` on the negative x - axis directly toward O, with initial speed V. Find the smallest (nonzero) value of the speed such that the particle does not return to P ? |
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Answer» Correct Answer - ` sqrt (lambdaq)/( 2 varepsilon_0m)` . As both have same charge tharge threfore repulion will take place when charge reaches from `P` to `O`. If we provide such a velocity that it come to `O` then it will not retum to `P` For miimum velocity it should reach `O` ` V_P ( KQ)/( sqrt ( R^2 + 3 R^2)) = (KQ)/(2R) & V_0 = (KQ)/R` From consevation of mechanical enrgy ` Delta U + Delta =0 rArr - delta K = Delta U` `1/2 mv^2 = q (Delta V)` `1/2 mv^2 = q (V_0 -V_P ) rArr 1/2 mv^2 = q [(Kq)/R - (KQ)/(2R)]` `1/2 mv^2 = (KQq)/(2R) rArr v= sqrt (Qq)/(Rm)` put `v= sqrt ( 1/(4 pi in_0) xx ( lambda(2 pi R)q)/(mR)) rArr v= sqrt (( almbdaq)/(2 in_0 m))`. |
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| 422. |
The electric potential V at any point x, y, z (all in meters) in space is given by `V=4x^2` volts. The electric field at the point (1m, 0, 2m) is……………..`V//m`.A. `-8hati`B. `8hati`C. `-16`D. `8sqrt(5)` |
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Answer» Correct Answer - A |
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| 423. |
A non-conducting ring of radius `0.5 m` carries a total charge of `1.11xx10^(-10)`C distributed non-uniformly on its circumference producing an electric field E everywhere is space. The value of the integral `int_(l=oo)^(l=0)-E.dI (l=0` being centre of the ring) in volt isA. `+2`B. `-1`C. `-2`D. `0` |
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Answer» Correct Answer - 1 `int_(l = oo)^(l = 0) - vec(E ) . D vec(l) = V_(l = 0) - V_(l = oo) = (1)/(4 pi in_(0)) (Q)/(R ) - 0` `= (9 xx 10^(9) xx 1.11 xx 10^(-11))/(0.5) = 2 V` |
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| 424. |
A non-conducting ring of radius 0.5 m carries a total charge of `1.11xx10^(-10) C` distributed non-uniformly on its circumference producing an electric field `vec(E)` every where in space. The value of the line integral `int_(i=oo)^(i=0) - vec(E).d vec(l)` (`l=0` being centre of the ring) in volts is : (Approximately)A. `+2`B. `-1`C. `-2`D. zero |
| Answer» Correct Answer - A | |
| 425. |
A circular ring carries a uniformly distributed positive charge and lies in the xy plane with center at the origin of the cooredinate system. If at a point (0,0,z) the electric field is E, then which of the following graphs is correct?A. B. C. D. |
| Answer» Correct Answer - 3 | |
| 426. |
An uncharged capacitor is connected to a battery. Show that half the energy supplied by the battery is lost as heat while charging the capacitor. |
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Answer» Let capacitance of a capacitor = C emf of the battery = V `:.` Charge given to the capacitor, q = CV Energy supplied by battery = work done by battery = qV Energy stored in the capacitor `= (1)/(2) CV^(2) = (1)/(2) qV` So, half energy is lost as beat while charging the capacitor. |
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| 427. |
A `2muF` capacitor is charged as shown in the figure. The percentage of its stored energy disispated after the switch S is turned to poistion 2 is A. `20%`B. `75%`C. `80%`D. `0%` |
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Answer» Correct Answer - C |
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| 428. |
Suppose the charge of a proton and an electron differ slightely. One of them is `-e`, the other is `(e+Deltae)`. If the net of electrostatic force and gravitational force between two hydrogen atoms placed at a distance `d` (much greater than atomic size) apart is zero. Then `Deltae` is of the order of [Given mass of hydrogen `m_(h)=1.67xx10^(-27)kg`]A. `10^(-20) C`B. `10^(-23) C`C. `10^(-37) C`D. `10^(-47) C` |
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Answer» Correct Answer - C Here, electrostiac force = gravitonal force `(k(e + Delta e)^(2))/(d^(2)) = (G m_(h) m_(h))/(d^(2))` `(e + Delta e)^(2) = (G m_(h) m_(h))/(k)` `= (6.7xx10^(-11)(1.67xx10^(-27))^(2))/(9xx10^(9))` `(6.7xx1.67xx1.67)/(9) xx10^(-74)` `e + Delta e = (2.076xx10^(-74))^(1//2) = 1.44xx10^(-37)` Hence `Delta e` is of the order of `10^(-37) C` |
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| 429. |
Suppose the charge of a proton and an electron differ slightely. One of them is `-e`, the other is `(e+Deltae)`. If the net of electrostatic force and gravitational force between two hydrogen atoms placed at a distance `d` (much greater than atomic size) apart is zero. Then `Deltae` is of the order of [Given mass of hydrogen `m_(h)=1.67xx10^(-27)kg`]A. `10^(-20)C`B. `10^(-23)C`C. `10^(-37)C`D. `10^(-47)C` |
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Answer» Correct Answer - C |
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| 430. |
A capacitor `C_(1)` is charged to a p.d.V. The charging battery is then removed and the capacitor is connected to an uncharged capacitor `C_(2)`. The final p.d. across the combination isA. `VC_(1)/(C_(1)+C_(2))`B. `VC_(2)/(C_(1)+C_(2))`C. `V(C_(1)C_(2))/(C_(1)+C_(2))`D. `V/(C_(1)+C_(2))` |
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Answer» Correct Answer - A The charge on condenser `C_(1)=Q_(1)=C_(1)V` If it is connected across uncharged condenser of capacity `C_(2)`, then p.d. across `C_(2)` is given by , `"potential"=Q_(1)/C_(2)=VC_(1)/(C_(1)+C_(2))` |
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| 431. |
A capacitor is charged by a battery. The battery is removed and another identical uncharged capacitor is connected in parallel. The total electrostatic energy of resulting system:A. increases by a factor of 4B. decreases by a factor of 2C. remains the sameD. increases by a factor of 2 |
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Answer» Correct Answer - D |
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| 432. |
The electric field at a point due to a point charge is `20 NC^(-1)` and electric potential at that point is `10 JC^(-1)`. Calculate the distance of the point from the charge and the magnitude of the charge.A. 2500 VB. 22500 VC. 2000 VD. 20500 V |
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Answer» Correct Answer - B `V=1/(4piin_(0))xxq/r=(9xx10^(9)xx25xx10^(-6))/10` = 22500 V |
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| 433. |
Three equal charges `Q` are placed at the three vertices of an equilateral triangle. What should be the va,ue of a charge, that when placed at the centroid, reduces the interaction energy of the system to zero ?A. `(-Q)/2`B. `(-Q)/3`C. `(-Q)/(2sqrt(3))`D. `(-Q)/(sqrt(3))` |
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Answer» Correct Answer - D `U_(1)=(3KQ^(2))/a` where a side of equilateral triangle `U_(1)=(3kQ^(2))/a+(3kQ.q)/(a//sqrt(3))` where q is the charge brought at the centre , `U_(f)=0 rArr q=(-Q)/(sqrt(3))` |
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| 434. |
A uniformly charged semicircular ring (ABCD) produces an electric field E0 at the centre O. AB, BC and CD are three equal arcs on the ring. Portion AB and CD are cut from either side and removed. Find the field at O due to remaining part BC. |
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Answer» Correct Answer - `(E_(0))/(2)` perpendicular to AD |
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| 435. |
A semicircular ring of radius 0.5 m is uniformly charged with a total charge of `1.5 xx 10^(-9)` coul. The electric potential at the centre of this ring is :A. 27 VB. 13.5 VC. 54 VD. 45.5 V |
| Answer» Correct Answer - A | |
| 436. |
Two parallel metal plates having charges `+Q` and `-Q` face each other at a certain distance between them.If the plates are now dipped in kerosene oil tank ,the electric field between the plates willA. became zeroB. increaseC. decreaseD. remain same |
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Answer» Correct Answer - C |
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| 437. |
Some charge is being given to a conductor. Then its potential : -A. maximum at surfaceB. maximum at centreC. same throughout the conductorD. maximum somewhere between surface and centre |
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Answer» Correct Answer - C |
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| 438. |
A capacity of capacity `C_(1)` is charged up to `V` volt and then connected to an uncharged capacitor of capacity `C_(2)`. Then final potential difference across each will beA. `(C_(2)V)/(C_(1)+C_(2))`B. `(C_(1)V)/(C_(1)+C_(2))`C. `(1+(C_(2))/(C_(1)))V`D. `(1-(C_(2))/(C_(1)))V` |
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Answer» Correct Answer - B |
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| 439. |
If identical charges `(-q)` are placed at each corner of a cube of side `b`, then electric potential energy of charge `(+q)` which is palced at centre of the cube will beA. `-(4sqrt(2)q^(2))/(pi epsilon_(0))`B. `(8sqrt(2)q^(2))/(pi epsilon_(0)b)`C. `-(4q^(2))/(sqrt(3)pi epsilon_(0)b)`D. `(8sqrt(2)q^(2))/(4pi epsilon_(0)b)` |
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Answer» Correct Answer - C |
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| 440. |
If identical charges `(-q)` are placed at each corner of a cube of side `b`, then electric potential energy of charge `(+q)` which is palced at centre of the cube will beA. `(8sqrt(2) q^(2))/(4 pi epsilon_(0) b)`B. `(-8sqrt(2) q^(2))/(pi epsilon_(0) b)`C. `(-4 sqrt(2) q^(2))/(pi epsilon_(0) b)`D. `(-4 q^(2))/(sqrt(3) pi epsilon_(0) b)` |
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Answer» Correct Answer - 4 Number of pairs `= 8` `U = (1)/(4 pi in_(0)) .(-q*q)/((sqrt(3) b//2)) xx 8 = (-4q^(2))/(sqrt(3) pi in_(0) b)` |
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| 441. |
Magnitude of electric field only on the x-coordinate as `vec(E)=20/x^(2) hat(i) V//m`. Find (i) The potential difference between two points A (5m, 0) and B (10m, 0). (ii) Potential at `x = 5` if V at `oo` is 10 volt. (iii) In part (i), does the potential difference between a and B depend on whether the potential at `oo` is 10 volt or something else. |
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Answer» Given, `vec(E)=20/x^(2) hat(i) V//m` We know that : `intdV=-int vec(E).vec(dr)" "implies" "underset(V_(1))overset(V_(2))(int)dV=-underset(x_(1))overset(x_(2))(int) 20/x^(2) dx` `:.` Potential difference, `DeltaV=20/x|_(x_(1))^(x_(2))" "implies" "V_(2)-V_(1)=20/x_(2)-20/x_(1)` (i) Potential difference between point A and B `(DeltaV" for A to B")` `V_(B)-V_(A)=20/10-20/5=-2` volt (ii) `DeltaV` for `x=oo` to `x=5` `V_(5)-V_(oo)=20/5-20/oo" ":." "V_(5)=10+4=14` volt (iii) Potential difference between two point does not depend on reference value of potential. So, the potential difference between a and B does not depend on whether the potential at `oo` is 10 volt ot something else. |
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| 442. |
If `V=x^(2)y+y^(2)z` then find `vec(E)` at (x, y, z) |
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Answer» Given `V=x^(2)y+y^(2)z` and `vec(E)=- (del v)/(del r)` `vec(E)=-[(delV)/(delx) hat(i)+(delV)/(dely) hat(j)+(delV)/(delz) hat(k)]" "implies" "vec(E)=-[2xy hat(i)+ (x^(2)+2yz) hat(j)+y^(2) hat(k)]` |
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| 443. |
A uniform electric field exists in a region of space. Potential at potential O,A,B and C are `V_(0)=0` and `V_(A)=-1V,V_(B)=-6V` and `V_(C)=-3V` respectively. Alll the cubes shown in fig have side length of 1m. ltbr. (a). Find `V_(P)-V_(Q)` (b). Find the smallest distance of a point from O where the potential is `-2V` |
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Answer» Correct Answer - (a). `5V` (b) `sqrt((2)/(3))m` |
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| 444. |
Three point charges are placed at the following points on x-axis : `3 muC` at `x = 0, -4 muC ` at `x = 50 cm` and `-5 muC` at `x = 50 cm` and `-5 muC` at `x = 120 cm`, Calculate the force on `-4 muC` charge. |
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Answer» Here, force of repulsion `(F_(1)) on -4 muC` charge by `-5 muC` charge will be towards left, Fig `F_(1) = (1)/(4pi in_(0)) (q_(1) q_(2))/(r^(2))` ` = (9xx10^(9)xx4xx10^(-6)xx5xx10^(-6))/((0.7)^(2)) = 0.367 N` And force of attraction by` + 3` muC charge on `-4 muC` charge will also be towards left. `F^(2) = ((9xx10^(9)xx4xx10^(-6)xx3xx10^(-6))/((0.5)^(2))) = 0.432 N` Total force,` F = F_(1) + F_(2)` `0.367 + 0.432 = 0.799 N` towards left. |
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| 445. |
STATEMENT 1: When a negative charge -q is released at a distance R from the centre and along the axis of a uniformly and positvely charged fixed ring of radius R, the negative charge does oscillation but not SHM. STATEMENT 2: The force on negative charge is always towards the centre of the ring but it is not proportional to the displacement from the centre of the ring.A. Statement-1 is true, Statement-2: is true, Statement-2 is a correct explanation for Statement-1.B. Statement-1 is true, Statement-2: is true, Statement-2 is NOT a correct explanation for Statement-1.C. Statement-1 is true but statement-2 is falseD. Statement-1 is false, Statement-2 is true |
| Answer» Correct Answer - A | |
| 446. |
Mid wat between the two equal and similar charfes , we place th third equal and similar charge. Which of the following statements is coarrect , concerned to the equilibrium along , the line jouning the charges ?A. The third charge experienced a net force inclined to the line joining the chargesB. The third charge is in stable equilibriumC. the third charge is ins table equilibriumD. The third charge experiences a net force perpendicular to the line joining the charges |
| Answer» Correct Answer - B | |
| 447. |
A charged particle having mass m I projected in a uniform electric field with a kinetic energy `K_(0)`. After time `t_(0)` it was observed that the kinetic enrgy of the particle was `(K_(0))/(4)` and its velocity was perpendicular to the field. (a). (a) How much more time is required for the particle to regain its lost kinetic energy? (b) Write the impulse of the electric force acting on the particle between the two points where its kinetic energy is `K_0`. Neglect all other forces on the particle apart from the electrostatic force. |
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Answer» Correct Answer - (a). `t_(0)` (b). `sqrt(6mK_(0))` |
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| 448. |
A particle is projected at a speed of u = 40 m/s in vertically upward direction in a place where exists a horizontal uniform electric field E0. The specific charge of the particle is `(4g)/(3E_(0))` . (a) Find the time after projection, when speed of the particle will be least. (b) Find the time (after projection) when displacement of the particle becomes perpendicular to its acceleration. (c) Assuming that the particle has been projected from a great height and the electric field is present in large region, what angle the velocity of the particle will make with horizontal after a long time? |
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Answer» Correct Answer - (a). `(36)/(25)s` (b). `(72)/(25)s` (c). `tan^(-1)((3)/(4))` |
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| 449. |
In the figure shown sphere `S_(1),S_(2)` and `S_(3)` have radii `R,(R)/(2)and (R)/(4)` respectively `C_(1),C_(2)` and `C_(3)` are centers of the three spheres lying in a plane Angle `angleC_(1)C_(2)C_(3)` is right angle. Sphere `S_(3)` has a uniformly spread volume charge density `4rho.` the remaining pat of `S_(2)` has uniform charge density of `2rho` and the left over part of `S_(1)` has a uniform charge density of `rho`. (a) Find electric field at a point A at a distance `(R)/(8)` from `C_(3)` on the line, `C_(2)C_(3)` (see figure) (b). Find electric field at point B at a distance `(R)/(4)` from `C_(2)` on the line `C_(3)C_(2)` (See figure) |
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Answer» Correct Answer - (a). `(sqrt(5))/(6)(rhoR)/(epsilon_(0))` (b). `(sqrt(41))/(24)(rhoR)/(epsilon_(0))` |
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| 450. |
A point charge `q_1 = 4.00 nC` is placed at the origin, and a second point charge `q_2 = -3.00 nC`, placed on the x-axis at x = + 20.0 cm. A third point charge `q_3 = 2.00 nC` is placed on the X-axis between `q_1, and q_2`. (Take as zero the potential energy of the three charges when they are infinitely far apart). (a) What is the potential energy of the system of the three charges if `q_3` is placed at x= + 10.0 cm?(b) Where should `q_3` be placed to make the potential energy of the system equal to zero? |
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Answer» Correct Answer - B::C::D a. `U=k((q_1q_2)/r_12+(q_1q_3)/r_13+(q_2q_3)/r_23)`…i Where `k=1/(4piepsilon_0)` b. Suppose `q_3` is placed at coordinate `x( gt 0.2m or 20cm)` them in eqn i of part a put `U=0, r_12=0.2m, r_13=x` and `r_23=(x-0.2)` Now, solving eq i we get the desired value of x. |
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