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This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
A charged particle P leaves the origin with speed `v=v_0` at some inclination with the x-axis. There is a uniform magnetic field B along the x-axis. P strikes a fixed target T on the x-axis for a minimum value of `B=B_0`. P will also strike T ifA. `B=2B_(0),v=2v_(0)`B. `B=2B_(0),v=v_(0)`C. `B=B_(0),v=2v_(0)`D. `B=B_(0)//2, v=2v_(0)` |
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Answer» Correct Answer - A::B |
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| 2. |
A charged particle entering a magnetic field from outside in a direction perpendicular to the fieldA. can never complete one rotation inside the fieldB. may or may not complete one rotation in the field dependent on its angle of entry into the fieldC. will always complete exactly half of a rotatioin before leaving the fieldD. may follow a helical path depending on its angle of entry into the field |
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Answer» Correct Answer - A |
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| 3. |
A particle with a specific charge s is fired with a speed v toward a wall at a distance d, perpendicular to the wall. What minimum magnetic field must exist in this region for the particle not to hit the wall?A. `v//sd`B. `2v//sd`C. `v//2sd`D. `v//4sd` |
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Answer» Correct Answer - A |
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| 4. |
A ring of area `A` and resistance `R` is placed on the axis of a solenoid. The mutual inductance between them is `M`. When the current in the solenoid changes at the rate of `I`, the magnetic moment of the ring isA. `ARMI`B. `AI//RM`C. `MRI//A`D. `AMI//R` |
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Answer» Correct Answer - A |
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| 5. |
A metal rod of length `l` pivoted at is upper end. It is released from a horizontal position. There is a uniform magnetic field `_|_` to its plane of rotation. When it becomes vertical, the p.d. across its ends is proportional toA. `l^(1//2)`B. `l`C. `l^(3//2)`D. `l^(2)` |
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Answer» Correct Answer - A |
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| 6. |
A charged particle begins to move in a magnetic field, initially parallel to the field. The direction of the field now begins to change, with its magnitude remaining constantA. The magnitude of the force acting on the particle will remain constant.B. The magnitude of the force acting on the particle will change.C. The particle will always move parallel to the field.D. The speed of the particle will change. |
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Answer» Correct Answer - B |
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| 7. |
The flux linked with a coil is `0.8Wb` when `2A` current flows thorugh it. If this current begins to increase at the rate of `0.4A//s`, the emf induced in the coil will beA. `0.02V`B. `0.04V`C. `0.08V`D. `0.16V` |
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Answer» Correct Answer - A |
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| 8. |
A long, narrow beam of electrons, of uniform cross-section consists of electrons moving with velcity `v` (`c=` velocity of light ). The ratio of the electric field to the magnetic field at any point near the beam isA. `v`B. `c`C. `c^(2)//v`D. `v^(2)//v` |
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Answer» Correct Answer - A |
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| 9. |
A thin, straight conductor lies along the axis of a hollow conductor of radius `R`. The two carry equal currents in the same direction. The magnetic field `B` is plotted against the distance `r` from the axis. Which of the following best represents the resulting curve?A. B. C. D. |
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Answer» Correct Answer - A |
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| 10. |
A rectangular, horizontal conducting frame carries current, flowing clockwise as seen from above,. `P` is a point vertically above the centre of the frame. The direction of the magnetic field at `P` due to the current isA. vertically upwardsB. horizontal, prallel to the loner sides of the frameC. vertically downwardsD. horizontal parallel to the diagonal of the frame |
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Answer» Correct Answer - A |
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| 11. |
A long, straight conductor lies along the axis of a ring. Both carry current `I`. The force on the ring is proportional toA. `I`B. `I^(3//2)`C. `I^(2)`D. zero |
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Answer» Correct Answer - A |
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| 12. |
A solenoid is connected to a cell. There is no resistance in the circuit. If the current `I` flowing in the circuit is plotted against time `t`, the slope of the curve `(dI//dt)` willA. increase with timeB. decrease with timeC. remain constantD. be almost infinite |
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Answer» Correct Answer - C |
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| 13. |
A long bar magnet moves with constant velocity along the axis of a fixed metal ring. It stars form a large distance from the ring, passes through the ring and then moves away far from the ring. The current `i` flowing in the ring is plotted against time `t`. Which of the following best represents the resulting curve?A. B. C. D. |
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Answer» Correct Answer - A |
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| 14. |
A small flat coil carrying current has magnetic moment `mu`. It is placed in an external magnetic field `B`. The maximum potential energy of the system can beA. `muB//2`B. `muB`C. `muB In 2`D. `2muB` |
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Answer» Correct Answer - A |
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| 15. |
An electron moving in a circular orbit of radius `r` makes `n` rotation per secound. The magnetic field produced at the centre has magnitudeA. `mu_(0) omegae//2r`B. `mu_(0) omega e//2pir`C. `mu_(0) omega e//4pir`D. `mu_(0) omega^(2)e//4pir` |
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Answer» Correct Answer - A |
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| 16. |
In a cell, or accumulatr battery, current flows inside the cell from the negatilve plate to the positive plate whenA. it drives currents through an external resistanceB. it is being charged from an external sourceC. its emf is being measured by a potentiometer and the balance position has been reached.D. when it is connected to a charged capacitor whose potential diefference is greater than its emf, and its positive and negative plates are connected to the plates of similar polarities of the capacitor. |
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Answer» Correct Answer - A |
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| 17. |
A charged particle moves undeflected in a region of crossed electric and magnetic fields. If the electric field is switched off, the particle has an initial acceleration `a`. If the magnetic field is switched off, instead of electric field, the particle will have an initial accelerationA. equal to 0B. `gt a`C. equal to `a`D. `lt a` |
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Answer» Correct Answer - C |
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| 18. |
A charged particle moves with velocity `vec v = a hat i + d hat j` in a magnetic field `vec B = A hat i + D hat j.` The force acting on the particle has magnitude F. Then,A. `F=0`, if `aD=dA`B. `F=0` if `aD=-dA`C. `F=0`, if `aA=-dD`D. `Fprop(a^(2)+b^(2))^(1//2)xx(A^(2)+D^(2))^(1//2)` |
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Answer» Correct Answer - A |
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| 19. |
A particle of charge ` +q` and mass `m` moving under the influence of a uniform electric field ` E hat(i)` and uniform magnetic field ` B hat(k)` follows a trajectory from ` P to Q` as shown in fig. The velocities at `P and Q` are ` v hat(i)` and ` - 2v hat(j)` . which of the following statement(s) is/are correct ? A. `E=3/4((mv^(2))/(qa))`B. The rate of work done by the electric field at `P` is `3/4((mv^(3))/a)`C. The rate of work done by the electric field at `P` is 0.D. The rate of work done by both the fields at `Q` is 0 |
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Answer» Correct Answer - A::B::D |
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| 20. |
A conductro `AB` carrying current `i` is placed vertically above and parallel to a long horizontal conductor `XY` carrying current `I`. Assume that `AB` is free to move and that the wires through which currents enter and leave it do no exert any forces on it. If `AB` is in equilibriumA. `i=I`B. `i` and `I` must flow in the same directiionC. the equilibrum of `AB` is usntableD. if `AB` is given a small vertical displacement it will undergo oscillations |
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Answer» Correct Answer - A |
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| 21. |
In which of the following situations will a charge experience no force?A. It is stationary in an electric field.B. It moves parallel to an electric field.C. It is stationary in a magnetic field.D. It moves parallel to a magnetic field. |
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Answer» Correct Answer - C::D |
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| 22. |
Two parallel conductors carrying current in the same direction attract each other, while two parallel beams of electrons moving in the same direction repel each other. Which of the following statement provide part of all of the reason for this ? (Choose the incorrect option)A. The conductors are electrically neutralB. The conductors produce magnetic fields on each other.C. The electron beams do not produce magnetic fields on each other.D. The magnetic forces caused by the electron beams on each other are weaker than the electrostatic forces between them. |
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Answer» Correct Answer - A::B::D |
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| 23. |
Two particles `X` and `Y` with equal charges, after being accelerated throuhg the same potential difference, enter a region of uniform magnetic field and describe circular paths of radii `R_(1)` and `R_(2)` respectively. The ratio of the mass of `X` to that of `Y` isA. `(R_(1)//R_(2))^(1//2)`B. `R_(2)//R_(1)`C. `(R_(1)//R_(2))^(2)`D. `R_(1)//R_(2)` |
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Answer» Correct Answer - C |
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| 24. |
A uniform electric field E is established between two parallel charged plates as shown in figure. An electron enter the field symmetrically between the plates with a speed u. The length of each plate is l. if the electron does not stricke any of the plates, find the angle of deviation of the electron as it comes out of the field at the outer end of plates. `[tan^(-1) ((eEl)/(mu^(2)))]` A. `E`B. `s`C. `l^(2)`D. `u^(-2)` |
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Answer» Correct Answer - A::B::C::D |
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| 25. |
`X,Y` and `Z` are parallel plates. `Y` is given some positive charge. Two electrons `A` and `B` start form `X` and `Z` respectively and reach `Y` in times `t_(A)` and `t_(B)` respectively.A. `t_(A)=t_(B)`B. `t_(A)=sqrt(2)t_(B)`C. `2t_(A)=t_(B)`D. `t_(A)=2t_(B)` |
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Answer» Correct Answer - D |
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| 26. |
An electron enters the region between the plates of a parallel plate capacitor at an angle `theta` to the plates. The plate width is `l`, the plate separation is `d`. The electron follows the path shown just missing the upper plate. Neglect gravity. Then, `A. `tan theta=2d//l`B. `tan theta=4d//l`C. `tantheta=8d//l`D. The data given is insufficient to find a relation between `d,l,theta`. |
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Answer» Correct Answer - B |
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