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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. |
गति |
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Answer» 5 |
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| 2. |
calculate the magnitude and direction of the torqueacting on the combination, if it is placed in an external electric field of 10^(4) NC^(-1)directed along X-axis. |
| Answer» SOLUTION :`1.17xx10^(-3)` N m | |
| 3. |
Calculate Mass defect, |
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Answer» SOLUTION :For `._(6)^(12)C, A=12, Z = 6, m_(P)=1.007825u` `m_(N)=1.008665u ' M = 12.000000 u` `DELTA M = [Zm_(P)+(A-Z)m_(n)-M]` `=[6(1.007825)+(12-6) (1.008665)-12.00]` `= [6xx1.007825+6xx1.008665-12]` `= [6.04695+6.05199-12.00]` `Delta M =[12.09894-12.00]=0.098944` |
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| 4. |
किसी अचालक पदार्थ के गोले को आवेश देने पर वह वितरित होता है |
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Answer» सतह पर |
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| 5. |
Which one of the following is not a unit of electric potential ? |
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Answer» `JC^(-1)` |
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| 6. |
एक आवेशित चालक की सतह के किसी बिन्दु पर विधुतीय-क्षेत्र की तीव्रता |
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Answer» शून्य होती है |
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| 7. |
whichone of thefollowingcurvesrepresents thegraph of pHduring titrationof NaOH and HCl (aq).? |
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Answer»
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| 8. |
What pressure should be applied to a lead block to reduce its volume by 10%? (Bulk modulus of lead =6 xx 10^9 N/m^2) |
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Answer» Solution :K = `vdp//dv` `THEREFOR` `DP = Kdv/v `6 xx 10^9 xx 10/100 = 6 xx 10^8 N/m^2` |
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| 9. |
A copper of rod (resistivity 2.2 xx 10^(-8)Omega -m) and an iron (resistivity 1.1 xx 10^(-8) Omega-m)rod of same length 70 cm each and same diameter 1.4 mm each are joined in series, then the combined resistance is |
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Answer» `1.5 XX 10^(-2) OMEGA` |
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| 10. |
Give an account of work done by Magnetic Lorentz force on moving charge and corresponding change in K.E. |
| Answer» Solution :If velocity (displacement) is perpendicular to LORENTZ FORCE the work done will be zero and hence there will no CHANGE in K.E. | |
| 11. |
The false statement in the following is |
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Answer» radiations are electromagnetic waves |
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| 12. |
Give the expression for limit of resolution of a microscope along with the meaning of the symbols used. |
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Answer» Solution :The limit of RESOLUTION of a MICROSCOPE is defined as the minimum linear separation( distance ) between two POINT objects for which they are just resolved OR just separated in the IMAGE. `dx = ( LAMBDA )/( 2 n sin theta )` |
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| 13. |
A small flat search coil of area 5 cm^(2) with 140 closely wound turns is placed between the poles of a powerful loud speaker magnet and then quickly snatched out of the field region.The total charge flown in the coil is 10.5 mC. If the resistance of thecoil is 0.6 Omega, what is the field strength of the magnet ? |
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Answer» |
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| 14. |
A uniform magnetic field of 0.3 T is established along the positive Z-direction. A rectangular loop in XY plane of sides 10 cm and 5 cm carries a current of I = 12 A as shown. The torque on the loop is _____ |
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Answer» Solution :use `tau = IA xx B ` and `F = Il xx B` (a) `1.8 xx 10^(-2)` N m along - y direction (b) same as in (a) ( c) ` 1.8 x 10^(-2) N` m along -x direction ( d) `1.8 xx 10^(-2) N` m at an ANGLE of `240^@` with the +x direction (e ) zero ( f) zero Force is zero in each case. Case (e) corresponds to stable, and case (f) corresponds to unstable equilibrium. |
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| 15. |
How many watts of energy is required to keep a black body in the form of a cube of side 1 cm at 2000 K ? (Temperature of surrounding is 27^(@)C and sigma=5.67xx10^(-8)"W m"^(-2)K^(-4) ) : |
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Answer» 444 W `E=sigma(T^(4)-T_(0)^(4))A=5*67xx10^(-8)[(2000)^(4)-(300)^(4)]xx6xx10^(-4)`. `E=544` warr. THUS correct choice is (B). |
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| 16. |
A photographic plate is directly in fornt of as small diffused source in the shape of a circular disc. It takes 12 s to get a good exposure. If the source is rotated by 60^@ about one of its diameters, the time needed toget the same exposure will be |
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Answer» 6s |
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| 17. |
An astronomical telescope has a large aperture to …... |
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Answer» reduce SPHERICAL aberration `THEREFORE` Resolution power `PROP` D. `therefore` Resolution power increases. |
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| 18. |
Human body radiates |
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Answer» microwaves. |
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| 19. |
For a circuit shown in Fig. find the value of resistance R_2 and current I_2 flowing through R_2 |
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Answer» SOLUTION :If equivalent resistance of parallel combination of `R_(1) and R_(2)` is R,then `R=(R_(1)R_(2))/(R_(1)+R_(2))=(10R_(2))/(10+R_(2))` According to Ohm.s law, `R=(V)/(I)` `R=(50)/(10)=5Omega RARR (10R_(2))/(10+R_(2))=5 rArr R_(2)=10Omega`. The current is EQUALLY DIVIDED into `R_(1) and R_(2)`. Hence `I_(2)=5A`. |
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| 20. |
भारत में वनों को सबसे बड़ा नुकसान उपनिवेश काल में हुआ? |
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Answer» रेलवे लाइन बिछाने |
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| 21. |
A : Kepler's third law of planetarymotion is validonly forinversesquareforces . R : Only inversesquare forces are alwayscentral . |
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Answer» If both Assertion & Reasonare true . ANDTHE reasonis the correct EXPLANATIONOF theassertion , then mark (1) |
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| 22. |
वे जातियाँ जिनका अस्तित्व ही समाप्त हो गया है वह है |
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Answer» लुप्तजातियाँ |
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| 23. |
What is meant by hysteresis ? |
| Answer» Solution :The phenomenon of LAGGING of magnetic INDUCTION BEHIND the magnetising FIELD is called hysteresis. Hysteresis. Hysteresis MEANS 'lagging behind'. | |
| 24. |
The gravitational force between two protons is attractive. Then the Coulomb force between the protons is |
| Answer» Solution :The MOON can escape only if there is no ORBITAL motion. The moon, while revolving round the earth has also orbital velocity round the SUN. The gravitational attraction of the sun provides the CENTRIPETAL force necessary for the orbital motion around the sun. | |
| 25. |
Waves that cannot be polarised are |
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Answer» ELECTROMAGNETIC WAVES |
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| 26. |
Attwo points S_(1) and S_(2) on a liquid surface two coherent wave sources are set in motion at t = 0 with the same phase. The speed of the waves in the liquid v = 0.5 m/s, the frequency of vibration eta = 5 Hz and the amplitude A = 0.04 m. At a point P of the liquid surface which is at a distance x_(1) = 0.30m from S_(1) and x_(2) = 0.34 m from S_(2) a piece of cork floats: (a) Find the displacement ofthe cork at t = 3 s. (b) Find the time t_(0)that elapse from the moment the wave sources were set in motion until the moment that the cork passes through the equilibrium position for the first time. |
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Answer» `Delta = 0.04m` wavelength `lambda = (v)/(n) = (0.5)/(5)` = 0.1m = `2pi xx 0.04 = (4pi)/(5)` The waves from `S_(1)` and `S_(2)` arrive at point P at DIFFERENT time `t_(1)` and `t_(2)` given as = `t_(1) = (0.3)/(0.5)` = 0.6s and `t_(2) = (0.34)/(0.5)` = 0.68s equation of motion of cork it `t_(0) = 3s` is `y = y_(1) + y_(2)` = `Asin(omega + t_(0) - t) Asin(omega+(t_(0) - t_(2)))` `A[sin(10pi(2.4)) + Asin(omega(t_(0) - t_(2)))]` = `0.04 xx sin (23.2pi)` = - 0.02344m. If we consider t = 0 the time when cork starts it motion then the resulting oscillation at cork is given as `y = A sin omegat + A sin(omega -(4pi)/(5))` = `Rsin(omegat -THETA)` `theta = tan^(-1) ((Asin(4pi//5))/(A + Acos(PI//5)))` = `70^(@) = (2pi)/(5)` rad Here initial phaseof `70^(@)` `(or (2pi)/(5) rad` will be there in cork motion when SECOND wave arrives at it. Thus time after which cork will pass through mean position is given as ` t = 0.68 + pi - (2pi)/((5)/(omega))` = `0.68 + (3pi)/((5)/(10pi))` = 0.68 + 0.06 = 0.74s. |
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| 27. |
What are dimesional formulae for magnetic induction : |
| Answer» SOLUTION :`B = F/qv = [M^1L^1T^-2]/([A^1T^1][L^1T^-1])` | |
| 28. |
In moon rock sample the ratio of the number of stable argon-40 atoms present to the number of radioactive potassium-40 atoms is 7:1. Assume that all the argon atoms were produced by the decay of potassium atoms, with a half-life of 2.5 xx 10^(9_ yr. The age of the rock is |
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Answer» `2.5 xx10^(9)` YR |
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| 29. |
Three thin prisms are combined as shown in figure. The refractive indices of the crown glass for red, yellow and violet rays are mu_r, mu_y and mu_v respectively and those for the flint glass are mu_r^', mu_y^r and mu_v^' respectively. Find the ratio A'/A for which (a) there is no net angular dispersion, and (b) there is no net deviation in the yellow ray. |
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Answer» `delta_y = delta_(EY) - delta_(ty)` ` =2 delta_(ey) - 2delta_(ry)` `= 2 (mu_y + 1)A - (mu_(re) -1)A` Similarlyuthe ANGULAR dispersion produced by the combination is `(a) For net angular dispersion to be ZERO, `delta_t - delta_t = 0 =2 (mu_(upsilon c) - mu_(tc)A` `=(mu_(upsilon t) - mu_(rt)A` rArr (A)/(A) = (2(mu_(upsilon c) - mu_(r c)`/((mu_(upsilon c) - uu_rc)` `= (2(mu_r - u_r))/((mu_r - mu))` (b) Fro net deviation in the yellow ray to be zero, `DELTA = -0` `rArr 2(mu_(CY) -1)A = (2(mu_(cy) -1))/((mu_(ty) -1))` `=(2(mu_y -1))/((mu_y -1))` |
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| 30. |
प्रकाश की एक किरण जब विरल माध्यम से सघन माध्यम में आती है, तब वह |
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Answer» अभिलंब से दूर मुड़ जाती है |
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| 31. |
The work function of a photosensitive element is 2eV. Calculate the velocity of a photoelectron when the element is exposed to a light of wavelength 4xx10^(3) A. |
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Answer» Solution :Einstein.s photoelectric equation is `(1)/(2)mv^(2)=(HC)/(lamda)-W_(0)` `(1)/(2)mv^(2)=(6.62xx3)/(4xx10^(3)xx10^(-10))xx10^(-26)-2xx1.6xx10^(-19)` `v^(2)=(1.765xx2)/(9.1)xx10^(12)` `v=sqrt((1.765xx2)/(9.1))xx10^(6)=6.228xx10^(5)ms^(-1)` |
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| 32. |
What is the mass of 1 curie of ""_(27)C^(60) ? Half life of ""_(27)C^(60) is 5.25 years: |
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Answer» `8.8 xx 10^(-6)kg` `N=(3.7 xx 10^(10))/(lambda)=(3.7 xx 10^(10) xx T)/(0.693)` `=(3.7 xx 10^(10) xx 5.25 xx 3.16 xx 10^(7))/(0.693)` `=8.85 xx 10^(18)` Mass of N atoms `=(60 xx 8.85 xx 10^(18))/(6.02 xx 10^(26)) kg` `=8.8 xx 10^(-7)kg` |
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| 33. |
In Millikans oil drop experiment, a charged drop of mass 1.8xx10^(-14)kg is stationary between its plates. The distance between its plates is 0.90 cm and potential difference is 2.0 kilo volts. The number of electrons on the drop is |
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Answer» 500 |
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| 34. |
Name the experiment, which establish the wave nature of moving electrons. |
| Answer» SOLUTION :DAVISSON GERMER EXPERIMENT | |
| 35. |
Assertion (A) : The positively charged nucleus of an atom has a radius of almost 10^(-15) m. Reason (R) : In a-particle scattering experiment the distance of closest approach for alpha -particles is of the order of 10^(-15) m. |
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Answer» If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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| 36. |
A gaseous mixture enclosed in a vessel of volume V consists of one gram mole of a gas LA with gamma=5//3 and another has B with gamma=7//5 at a certain temperature T. The gram molecular weights of the gases A and B are 4 and 32 respectively. The gases A and B do not react with each other and are assumed to be ideal. The gasesous mixture follows the equation PV^(19//13)= constant in adiabatic processes. a. Find the number of gram moles of the gas B in the gaseous mixture. b. Find the speed of sound in the gaseous mixtrue at T=300K. c. If T is raised by 1 K from 300 K, find the percentage change in the speed of sound in the gaseous mixture. |
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Answer» |
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| 37. |
A galvaometer is converted into a ammeter using a |
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Answer» HIGH RESISTANCE in SERIES |
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| 38. |
क्रिस्टल के घनत्व को कम करने वाला बिंदु दोष है |
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Answer» शॉट्की दोष |
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| 39. |
If one of the slits in Young's double-slit experiment is fully closed, the new pattern has ______________ central maximum in angular size. |
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Answer» |
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| 40. |
The order of the size of nucleus and Bohr radius of an atom respectively are |
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Answer» `10^(-14)m, 10^(-10) m` |
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| 41. |
In the cylotron, as radius of the circular path of the charged particle increases (omega= angular velocity, v = linear velocity ) |
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Answer» both `omega` and v INCREASES `v=((Bq)/(m))r` As r increases, v increases. `omega=(v)/(r )=(Bq)/(m)` = constant (if mass is taken constant) |
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| 42. |
A multimode graded index fibre exhibits total pulse broadening of 0.1 us cover a distance of 1.5km. What is the maximum possible band width on the link assuming no inter symbol interference? |
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Answer» 10MHz `B_(T)=(1)/(2tau)=(1)/(2xx0.1xx10^(-6))=5MHz` |
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| 43. |
When dilute HCl is added to sodium carbonate , gas evolved is ........ |
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Answer» Hydrogen |
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| 44. |
An ionization chamber with parallel conducting plates as anode and cathode, has 5 xx10^7 electrons and the same number of singly charged positive ions per cm^3. The electrons are moving towards the anode with velicty 0.4m/s. The current density from anode to cathode is 4mu A//m^2. The velcoity of positive ions moving towards cathode is |
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Answer» `0.4ms^(-1)` |
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| 45. |
Two paper screens A and B are separated by a distance of 100 m. A bullet pierces A and then B. The hole in Bis 10 cm below the hole in A. If the bullet is travelling horizontally at the time of hitting the screen A, calculate the velocity of the bullet when it hits the screen A. Neglect the resistance of paper and air. |
Answer» Solution : The situation is shown in fig. `d=u sqrt((2(h_(1)-h_(2)))/g)` `100 = usqrt((2 XX 0.1)/9.8)` `u= 700 m//s` |
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| 46. |
sqrt 9 is a number. |
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Answer» Irrational |
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| 47. |
In Young's double-slit experiment, the intensity at a point P on the screen is half the maximum intensity in the interference pattern. If the wavelength of light used is lambda and d is the distance between the slits, the angular separation between point P and the center of the screen is |
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Answer» `sin^(-1)((lambda)/(d))` |
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| 48. |
To get three images of a single object, one should have two plane mirrors at an angle of ….. |
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Answer» `90^@` where `theta` is the angle between two plane mirrors Now TAKING n = 2 `therefore2+1=(360^@)/(theta)` `therefore theta =(360^@)/(3)=120^@` |
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| 49. |
The focal length of a spherical mirror of radius of curvature 30 cm is: |
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Answer» 10 cm |
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| 50. |
Elight water drops, each of radius 'r' collide to form a bigger drop of radius R. Then R is equal to |
| Answer» ANSWER :A | |
