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Most important question for bihar board

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Dear Student is most important question for bihar board. It is test series question and it is minor test – 3  (See total set of test click). It is Bihar board important objective question and most important question for board. It is vvi question for state board exam. Student can learn important physics question for board exam. It is class 12 important question of physics and download physics important questions pdf for board exam.

Most important question for bihar board

हैलो student यह Bihar board के लिए important question का test series है. यह bihar board class 12 का important question का test series है और कोई भी student यहाँ से test देकर board exam में best mark ला सकता है. student के लिए physics का vvi question है. Class 12 का important question बोर्ड के लिए है. physics vvi question class 12 के लिए है. यह Minor Test-2 है (सारा सेट देखने के लिए click करें).

 

         Section – A


Note:- Section-A का सारा question Objective है और section – B का सारा question subjective है. Test देने के बाद नीचे जाकर इस test का solution का PDF download कर लीजिए !!


 

(1)  If an ion passes un-deflected by crossed electric field vector and magnetic field vector. If E = 20 kVm-1 and B =1400 G, then what will be velocity of charge particle.

(a)  142 km/s

(b)    500 m/s

(c) 1.28 km/h

(d)    2.89  cm/s

एक आयन किसी क्रॉस्ड विधुत-क्षेत्र और चुम्बकीय क्षेत्र से बिना विचलन के गुजर जाती है. अगर E = 20 kVm-1 और B =1400 G है तो आयन के वेग का मान क्या है ?

(a)  142 km/s

(b)    500 m/s

(c) 1.28 km/h

(d)    2.89  cm/s

 

(2) two straight parallel wires both carrying 10 A current in the same direction attract each other by a force of 10-3 N. if both current are doubled the force of attraction will be:-

(a) 10-3 N

(b)   2 x 10-3 N

(c)    4 x 10-3 N

(d)   0.25 x 10-3 N

दो सीधा समांतर तार जिसमें प्रत्येक में विधुत धारा 10 A सामान दिशा में बह रही है और वह एक-दुसरे को 10-3 N के बल से आकर्षित करती है. अगर दोनों विधुत-धारा को दुगुना कर दिया जाए तो आकर्षण बल का मान क्या होगा?

(a) 10-3 N

(b)   2 x 10-3 N

(c)    4 x 10-3 N

(d)   0.25 x 10-3 N

 

 

(3) A straight conductor is placed at right angle to the direction of a uniform magnetic field. When a current flows in the conductor it will experience

(a) a force in the direction of the field

(b) a force in the opposite direction of the field

(c) a force at right angle to the field

(d) none of these

एक सीधे चालक को किसी एक-समान चुम्बकीय क्षेत्र में लंबबत दिशा में रखा गया है. जब चालक में विधुत धारा प्रवाहित होगी, तो चालक पर :-

(a) चुम्बकीय-क्षेत्र की दिशा में बल लगेगा.

(b) चुम्बकीय क्षेत्र के दिशा के विपरीत में बल लगेगा.

(c) चुम्बकीय क्षेत्र के दिशा के लंबबत दिशा में बल लगेगा.

(d) इनमें कोई नहीं.

 

(4) A current carrying conductor produces

(a) an electric field only

(b)a magnetic field only

(c)   both electric and magnetic field

(d) none of these

एक विधुत धारा प्रवाहित चालक उत्पन्न करता है :-

(a) केवल विधुत क्षेत्र

(b) केबल चुम्बकीय क्षेत्र

(c) चुम्बकीय और विधुतीय क्षेत्र दोनों.

(d) इनमें कोई नहीं.

 

(5) Which of the following is not the unit of magnetic field?

(a) Tesla (T)

(b)   Weber/m2

(c)  Newton/Ampere-meter

(d)  Weber-m2

निम्नलिखित में कौन चुम्बकीय क्षेत्र का मात्रक नहीं है ?

(a) टेसला (T)

(b)   वेबर/मीटर2

(c)  न्यूटन/एम्पेयर-मीटर

(d)  वेबर-मीटर

 

(6) A uniform magnetic field is produced by:-

(a)  A straight current carrying wire

(b) current carrying circular loop

(c) Current carrying long solenoid

(d)    none of these

एक-समान चुम्बकीय क्षेत्र निम्नलिखित में किसके द्वारा उत्पन्न होता है :-

(a) एक सीधा विधुत-वाही तार के कारण

(b) एक विधुत-वाही वृतीय लूप के कारण.

(c) विधुत-वाही लम्बे सोलेनोआइड के कारण

(d) इनमें कोई नहीं.

 

 

(7) By mistake a voltmeter is connected in series and ammeter is connected in parallel with a resistance in an electrical circuit what will happen to the instrument:-

(a) Voltmeter is damaged

(b) ammeter is damaged

(c)  both are damaged

(d) none is damaged

एक प्रतिरोध के साथ गलती से वोल्टमीटर को श्रेणी-क्रम में और आमीटर को समांतर क्रम में जोड़ दिया गया है तो इन यंत्रों के साथ क्या होगा ?

(a) वोल्टमीटर ख़राब हो जाएगा

(b) आमीटर ख़राब हो जाएगा

(c) दोनों ख़राब हो जाएगा

(d) कोई ख़राब नही होगा.

 

 

(8) To deflect a magnet of moment M from the direction of field by 1800 degree the work done is:-

(a)  MB

(b)   zero

(c)   infinite

(d)   2MB

किसी चुम्बक, जिसकी चुम्बकीय आघूर्ण M है को चुम्बकीय क्षेत्र की दिशा से 1800 के कोण तक घुमाया जाता है तो कितना कार्य करना पड़ेगा ?

(a)  MB

(b)   zero

(c)   infinite

(d)   2MB

 

 

(9) A magnet of pole strength P is divided into four parts such that its length and breadth is half each time now the pole strength of different parts will be:-

(a) P/4

(b)  P/8

(c)  P/2

(d)  4P

किसी चुम्बक का ध्रुव-सामर्थ्य P है अगर इसे चार भागों में इस तरह बाटा जाये कि प्रत्येक बार में इसका लम्बाई और चौड़ाई आधी हो जाए तो अब प्रत्येक हिस्से का ध्रुव-सामर्थ्य होगा ?

(a) P/4

(b)  P/8

(c)  P/2

(d)  4P

 

(10) At any point on the perpendicular bisector of a bar magnet

(a) Magnetic field is zero

(b) Magnetic potential is zero

(c) Magnetic field and potential both are zero

(d) none of these

किसी छड़ चुम्बक के लम्बसम्धिभाजक रेखा के किसी बिंदु पर :-

(a) चुम्बकीय क्षेत्र शुन्य होता है.

(b) चुम्बकीय विभव शुन्य होता है

(c) चुम्बकीय क्षेत्र और चुम्बकीय विभव का मान शुन्य होता है

(d) इनमें कोई नहीं

 

 

(11) Two wires are held perpendicular to the plane of paper at 5 m apart. They carry current of 2.5 ampere and 5 ampere in same direction then the magnetic field strength at the point Midway between the wires will be:-

(a) μ0/4π

(b)  μ0/2 π

(c)    3μ0/2π

(d)  zero

दो तार किसी पेपर के लंबबत 5m के दूरी पर स्थित है. अगर इसमें 2.5 एम्पियर और 5 एम्पियर की विधुत-धारा समान दिशा में प्रवाहित हो रही है तो दोनों तारों के मध्य बिंदु पर चुम्बकीय-क्षेत्र का मान होगा.

(a) μ0/4π

(b)  μ0/2 π

(c)    3μ0/2π

(d)  zero

 

 

(12) the magnetic field due to a short magnet at a distance r proportional to

 (a) r

(b)   r-1

(c)   r-2

(d)   r-3

किसी लघु-चुम्बक से r दूरी पर चुम्बकीय-क्षेत्र का मान किसके समानुपाती होता है :-

 (a) r

(b)   r-1

(c)   r-2

(d)   r-3

 

 

(13) Which of the following is likely to have the large resistance?

(a)  a galvanometer

(b)  an Ammeter

(c) Milliameter

(d)  voltmeter

निम्नलिखित में कौन एक बड़े प्रतिरोध के जैसा कार्य करता है ?

(a) एक गैल्वेनोमीटर

(b) एक आमीटर

(c) मिली-आमीटर

(d) एक वोल्टमीटर

 

(14) An electron and a Proton having equal Momenta enter a uniform magnetic field at right angles to the field lines.  What is the ratio of radii of paths?

(a)  1 : 1

(b)  1 : 2

(c)   2 : 1

(d)  None of these.

एक इलेक्ट्रौन और एक प्रोटॉन समान संवेग से किसी एक समान चुम्बकीय क्षेत्र में क्षेत्र के साथ समकोण बनाकर उसमें प्रवेश करती है. इनके रास्ते के त्रिज्यों का अनुपात क्या होगा ?

(a)  1 : 1

(b)  1 : 2

(c)   2 : 1

(d) इनमें कोई नहीं

 

(15) Biot-savart law is analogous to

(a)  Coulomb’s law

(b)  Gauss’s law

(c)   Stoke’s law

(d)   Newton’s laws of motion

बायो-सेवार्ट का नियम किसके अनुरूप है

(a) कुलम्ब के नियम

(b) गौस का नियम

(c) स्टोक का नियम

(d) न्यूटन के गति का नियम

 

(16) Proton and α-particle enters in stable uniform magnetic field with same kinetic energy. If the radius of circular path are rp and rα  , then:-

(a)     rp /rα =2

(b)    rp /rα = 1/2

(c)      rp =rα =

(d)    rp <rα

 

(17) A electron is moving in positive direction of x-axis. Electric field is presented in

– ve  direction of y-axis. What should be the direction of suitable magnetic field, so           that net force on electron is zero.

(a) along +ve z-axis

(b) along negative z-axis

(c) along –ve y-axis

(d) NOT

(18) What is the value of flowing current through long straight wire; if developed                     magnetic field is 2mT at 10cm from wire.

(a) 500 A

(b) 1000 A

(c)  250 A

(d)  2000 A

(19)Any current carrying wire is wended in form of circular arc of radius R, which make         angle θ at centre, then magnitude of magnetic field at centre O will be:-

(a)    ​\( \frac{\mu _{0}I\\theta }{2R} \)

(b)     ​\( \frac{\mu _{0}I\\theta }{360R} \)

(c)   ​\( \frac{\mu _{0}I\\theta }{720R} \)

(d)  Zero

(20) In uniform magnetic field, if in the circular motion of charge particle v and R are              respectively speed and radius of circle, then which of the following proportionality is          correct?

(a)     ​\( v\oe \frac{1}{R^{2}} \)

(b)    ​\( v\oe \frac{1}{R} \)

(c)    ​\( v\oe R \)

(d)    ​\( v\oe R^{2} \)

(21)  Due to generating the strong magnetic field, near the static (at rest) charge;

(a) Positive charge will be move in direction of magnetic field.

(b) Negative charge will be move in opposite direction to magnetic field.

(c)  Spin motion developed in charge.

(d)  Charge will be at rest.

(22) If Shunt is uses in Ammeter, then its measuring range:-

 (a) Increases

(b)  Decreases

(c) Constant

(d)  NOT

(23) At the centre of current flowing circular loop magnetic field is B. If without changing         current radius of loop to be doubled, then what will be magnetic field at centre?

(a)   B/4

(b)   2B

(c)     B/2

(d)    4B

(24) If the radius of circular coil a, no. of turns n in which current I current is flowing,             then value of magnetic field at its centre will be:-

(a)     ​\( \frac{\mu _{0}nI}{2a} \)

(b)      ​\( \frac{\mu _{0}In}{a} \)

(c)    ​\( \frac{2\mu _{0}nI}{a} \)

(d)    NOT

(25) A Galvanometer may be converted into voltmeter; with joining:-

(a) High resistance in parallel

(b)  High resistance in series

(c)  Low resistance in series

(d)  Low resistance in parallel

(26) If the radius of circular coil a, no. of turns n in which current I current is flowing,              then value of magnetic field at its centre will be:-

(a)   ​\( I^{-1}ML^{0}T^{-2} \)

(b)

(c)

(d)   NOT

(25) A Galvanometer may be converted into voltmeter; with joining:-

(a) High resistance in parallel

(b)  High resistance in series

(c)  Low resistance in series

(d)  Low resistance in parallel

(26) Dimension formulae of magnetic field is:-  

(a)  I-1ML0T-2

(b)    I0MLT-2         

(c)     IM

(d) IM-1L-1T-2

(27) Torque experienced by a current-loop in magnetic field (​\( \underset{B}{\rightarrow} \)​)having magnetic dipole moment (​\( \underset{m}{\rightarrow} \)​) is:-

(a)  Torque =  ​\( \underset{m}{\rightarrow}\times \underset{B}{\rightarrow} \)

(b)  Torque =  ​\( \underset{B}{\rightarrow}\times \underset{m}{\rightarrow} \)

(c)  ​\( \underset{B}{\rightarrow} \)​= Torque ​\( times \underset{m}{\rightarrow} \)

(d) ​\( \underset{B}{\rightarrow} \)​ = ​\( \underset{m}{\rightarrow}\times \)​ Torque

(28) Magnetic field of 5 T is equal to:-

   (a) 5 Wb/m2                    

  (b)   5 ×105 Wb/m2

(c) 5 ×103 Wb/m2

(d) 5 ×102 Wb/m2

(29) At the centre of current carrying circular coli magnetic field is:-

(a)  In the plane of coil

(b) Perpendicular to plane of coil

(c)  may be at any angle with axis of coil

(d)  All are wrong

(30) The magnetic field at a distance ‘r’ from a current element varies as:-

(a)   r

(b)   r-1

(c)   r2

(d)     r-2

(31) If a current I flow along an infinitely long straight thin hollow tube then the                     magnetic field at any point inside the tube is:-

(a) zero

(b) infinite

(c)  ​\( \left ( \frac{\mu _{0}}{4\pi } \right )\frac{2I}{r} \)

(d) none of these

(32) If two parallel wires carry current in the opposite directions, the forces between                them will be

(a)  zero

(b)   attractive

(c)  repulsive

(d)   infinite

(33) Any circular coil having radius r, turns n in which current I is flowing, then magnetic          field at centre is directly proportional to:-

(a)    I & r

(b)     n & r

(c)      I &   1/r

(d)     I & 1/n

(34) An ideal ammeter has:-

(a) zero resistance

(b)  infinity resistance

(c) Both ‘A’ and ‘B’

(d)  None of these.

(35) In moving coil galvanometer, the deflection θ(in radian) is related to electric current         (i) through it as

         (a)  i  α   tan θ

(b)  i  α θ

(c)  i α   θ 2

(d)  i  α   1/θ

Section-B

(1)  A very small element of wire is placed of length 1cm placed at origin along x-axis             and electric current of 10A flowing in positive x-direction. Find magnetic field at y-           axis at 0.5m.

(2) Explain the meaning of current sensitivity and voltage sensitivity.

(3) What is Amperes circuital law?

(4) Shunt is suitable to prevent the galvanometer by high current. Explain how?

(5) Two long and parallel straight wires A and B carrying currents of 8 A and 5 A in the           same direction are separated by a distance of 4 cm. Estimate the force on a 10cm             section of wire A.

(6) Define unit of Ampere on the basis of force between two current carrying wire.

(7) Find the expression of magnetic field intensity at the centre of a loop of current I and       radius R (making angle at θ centre) with the help of Biot-sevart’s law.

(8) Write about the Fleming left hand rule.

(9) When a charge particle is projected in magnetic field then what is path of motion of          charge in following cases:-

(a) When charge is projected along magnetic field.

(b) When charge is projected perpendicular to magnetic field

(10) A circular coil of wire consisting of 100 turns, each of radius 8 cm carries a current          of 0.4 ampere. What is the magnitude of magnetic field B at the centre of coil?

(11) What is angle of dip? What changes occurs in angle of dip when goes from north              pole to South Pole.

(12) Write difference between electric field line and magnetic field line.

(13) Draw the shape of magnetic line of force due to long solenoid and infinity current              carrying wire.

(14) A horizontal overhead power line carries a current of 90A in east to west direction.           What is the magnitude and direction of the magnetic field due to current 1.5m below         the line.

(15) A solenoid of length 0.5 m has a radius of 1 cm and is made up of 500 terms. It               carries a current of 5 ampere. What is the magnitude of magnetic field inside the              solenoid?

(16) What is Biot-sevart’s law? Write it in vector form.

(17) Derive the value of magnetic field at near point due to long current carrying wire.

(18) A charge particle Q is projected in uniform magnetic field B. If mass of particle is m          and velocity is v. Find time period of circular motion.

                                          Long Answer Question

(19) Explain the Construction, principle and working method of Cyclotron. And write how         due to it positive charge may be accelerated?

(20) What is solenoid? Derive value of magnetic field at inside point of long solenoid with         the help of Ampere’s circuital law.

(21) Write about the moving coil galvanometer.

(i) principle

(ii) construction

(iii)   working function

(22) Explain the Construction, principle and working method of Cyclotron. And write how          due to it positive charge may be accelerated?

(23) Find the magnetic field due to bar magnet at equatorial position.

(24) Write the value of following:-

(a) Force on charge particle in magnetic field

(b) Force on electric current in magnetic field

(c) radius of charge particle when projected perpendicular to magnetic field.

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