SAMPLE PAPER I. Time Allowed : 3 hours Maximum Marks : 70

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Oswald Quinn
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1 SAMPL PAPR I Time Allowed : 3 hous Maximum Maks : 70 Note : Attempt All questions. Maks allotted to each question ae indicated against it. 1. The magnetic field lines fom closed cuves. Why? 1 2. What is band pass filte How does magnifying powe of a micoscope change on deceasing the apetue of its objective? 1 4. Name the pat of lectimagnetic spectum which is suitable fo Physical theapy TV communication Why is enegy distibution of ay continuous? 1 6. A point souce of light is at the focus of a convex lens. What is the type of efacted wavefont? 1 7. Dawn a gaph showing vaiation of de Boglie wavelength of an electon with the vaiation of its momentum 1 8. All the cells ae identical each of emf and intenal esistance. What is the cuent passing though R. 2 R 9. What is a epeate? xplain with the help of a diagam. How does it incease the communication ange [XII Physics]

2 10. In a wie connected acoss a souce, dift speed and electic field ae v and espectively. The wie is stetched unifomly of double the length, what will be new dift speed electic field Sketch the output wave fom fom an gate. The input A and B ae shown in the figue. If the output of above gate is fed to a Not gate, name the gate so fomed. 2 A B ? 12. A chaged paticle of chage q and mass m is acceleated though potential diffeent V befo enteing a magnetic field B, pependicula to the diection of motion. What will be the adius of cicula path 2 A cicula coil of adius is caying cuent I. at what distance fom the cente of loop on the axis magnetic field is one eight the magnetic field at the cente. 13. P and Q ae long staight conductos distance apat. N is a point in the plane of wies 4 distance away fom P caying cuent I. What is the magnitude and diection of cuent in the wie Q, so that net magnetic field at N is zeo. [XII Physics] 184.N 14. In an electiomagnetic wave popagating along + x-axis electic field vecto is y = 4 x 10 3 Cos (3 x 10 8 t 1.5 x) V/m. What is the fequency of emwave amplitude of magnetic field. 15. A and B ae two concentic metallic spheical shell of adii a and b having chage q and Q espectively. How much wok will be done in moving a test chage q 0 fom A to B (a < b) What is the SI unit of adioactivity. xpess cuie in SI unit. The mean life of adio active substance is 2400 ys. What is its half life 2 P Q

3 17. What is meant by tem modulation? Daw a block diagam of a simple modulato fo obtaining an AM signal In intefeence patten obtained in young s double slit expeiment, explain how will the angula width of finge be affected if Slits sepeation is inceased Sceen is moved away (iii) xpeiment is pefomed in a dense medium 1+½+½ State Gauss s law in electostatics. Find net electic flux and chage enclosed by the cube of side a. Given 0 xi y x 20. In an atom enegy of electon in n th obit is atomic numbe. z 13.6 Z n n 2 2 ev, whee Z is What is the shotest and longest wave length of emitted adiation in singly ionized He With the helps of a schematic diagam explain the pinciple and woking of a cycloton. 3 A ba magnet of magnetic moment Mv held in magnetic field of stength B. What is maximum toque on the magnet wok done in tuning it fom stable equilibium to unstable equilibium. 22. A paallel plate capacito of capacitance 4.8 F has been chaged by a battey of 6 V. Afte disconnecting the battey dielectic medium of dielectic contant 5 in intoduced between its plates Find new capacitance. What is the atio of electostatic enegy stoed befoe and afte. (iii) Calculate new potential diffeence acoss the plates [XII Physics]

4 23. Define mutual inductance. Wite its SI Unit. Deive an expession fo mutual inductance of a system of two concentic and coplane cicula loop P and Q of adii a and b and numbe of tun N 1 o N 2 espectively (a << b). 24. State the pinciple of a potentiomete. In the following figue find the length PJ whee J si null deflection position. Given PQ = 400cm, Resistance of PQ is 20, Dive cell emf = 4V and 1 = 40 mv. 25. What is photo electic efect. Two monochomatic adiations, blue and violet, of the same intensity, ae incident on a photo sensitive suface and cause photo electic emission. Would the numbe of electons emitted pe second and the maximum kinetic enegy of the electons, be equal in the two cases? Justify you answe Aditya paticipated in a goup discussion in his school on Human eye and its defects in the evening he noticed that his fathe is eading a book by placing it at a distance of 50 cm o moe fom his eye. He adviced him fo his eye check-up. Suggest the focal length/powe of the eading spectacle fo him, so that he may easily ead the book placed at 25 cm fom eye. Name the value displayed by Aditya. 27. Deive lens makes fomula fo a double convex lens of adii R 1 and R 2 and efaction index n 2 of the mateial of lens kept in a medium of efactive index n 1. How will this lens behave if n 1 > n 2, tace the equied ay diagam. Daw a labelled diagam of compound micoscope fo the fomation of image. Deive an expession fo the magnifying powe of a compound micoscope. 28. Deive an expession fo impedence of a seies LCR cicuit connected to an ac souce. When does its value become minimum. Sketch gaph X L Vs v X C Vs v (iii) Z Vs v. Deive the elationship between the peak and ms value of cuent in an ac cicuit. Fo cicuits used fo tansmission of electic powe a low powe facto implies lage powe loss in the tansmission explain. 5 [XII Physics] 186

5 29. With the help of cicuit diagam of an npn tansiste in common emitte mode, explain its use as an amplifie. Dawn the output vesus input voltage cuve and mak egion in which the tansiste is used a switch, and amplifie. Daw fowad and evese chaacteestic cuves of a pn junction diode. xplain biefly with the help of a cicuit diagam, how a pn junction diode woks as a full wave ectifie. If fequency of input ac signal is f what is the fequency of output. 187 [XII Physics]

ELECTROSTATICS::BHSEC MCQ 1. A. B. C. D.

ELECTROSTATICS::BHSEC MCQ 1. A. B. C. D. ELETROSTATIS::BHSE 9-4 MQ. A moving electic chage poduces A. electic field only. B. magnetic field only.. both electic field and magnetic field. D. neithe of these two fields.. both electic field and magnetic