Page 1 : Roth NO. ect ED cncnosiigs, , , , Total No. of Questions : 26] [Total No. of Printed Pages : 4, , XIIKDAR21, 5001-C, PHYSICS, , Time : 3 Hours] [Maximum Marks : 70, , Section—A _ 1 each, , 1. What is the order of resistivity of an insulator ?, , Vv, , From where does the electrical energy come in a generator ?, , 3. Which part of the electromagnetic spectrum is suitable for treatment, , of cancer tumours 2 %- ¢% °, 4. How intensity of incident light effects photoelectric current ?, 5. For which diode, the output voltage is a regulated voltage ?, Section-B 2 each, , 6. When is the force on a moving charage due to magnetic field, maximum and when is it minimum ?, , Or, , Give two factors by which the current sensitivity of a moving coil, galvanometer can be increased.,, , i. Distinguish between average value and r.m.s. value of an alternating é, current., , , , XIIKDAR21—5001-C, , ‘ Turn Over, B-1-C | j, , , , Scanned with CamScanner

Page 2 : ee, , 10., , 16., , XIIKDAR21—5001-C, , B-1-C, , (2), , Can an electromagnetic wave be deflected by magnetic or electric, field ? Explain., , Write the conditions for total internal reflection to take place,, (a) What is Communication System ?, (b) Name the elements of Communication System.: ~ ,, , Section—C 3 each, Deduce Ohm’s law using the concept of drift velocity. _, State Coulomb’s law in electrostatics. Express it in vector form., Or . , Calculate electric field intensity at a point on the axial line of a, , dipole., , Explain how the internal resistance of a primary cell can be, , determined using a potentiometer ?. ~, , An electron enters a magnetic field of 5 T intensity with a velocity, of 5 x 10° ms? at an angle of 30° with the field. Find the, , magnitude of the force acting on the electron., , State Ampere’s circuital law. Derive an expression for the magnetic, , field due to a current carrying straight solenoid., , In Young’s interference experiment, the ratio of intensity at the, maxima and minima in the interference pattern is 25 : 9. What will, be the ratio of amplitude of two waves 2, , Scanned with CamScanner

Page 3 : (3), , 17. (@) What ‘do you mean by dual nature of matter waves ?, _(b) Obtain de-Broglie equation for a material particle., iG 18. ‘What is Radioactivity ? Deduce the relation N = Ny.e™., 19. Distinguish between isotopes and isobars. Give examples., , 20. What is a Rectifier ? Explain the working of p-n junction diode as, , full wave rectifier., , , , 21. Explain with the help of circuit diagram, the action of PNP or NPN, , transistor., 22. Explain ground wave propagation of radio waves., Section=D 4, , 23. Rekha and Ruhi were classmates. Rekha found out that Ruhi was, not able to see the letters on the board properly and also complained, of frequent headaches. Rekha suggested to Ruhi to get her eyes, checked. Ruhi followed Rekha’s suggestion and thanked her saying —, she felt comfortable after wearing the spectacles. Now answer the, , following questions :, , Questions :—, , (i) What was the eye defect that Ruhi had ?’%*, (ii) How can it be corrected ?, , (iii) Rekha was a true friend. Justify., , XIIKDAR21—5001-C “ue, , B-1-C a Turn “A, , Scanned with CamScanner

Page 4 : (4), , Section-E 5 each, , 24. (a) Using Gauss’s law, prove that electric field at a point due to 4, . uniformly charged plane sheet is independent of-distance from, it., (b) How is the field directed if the sheet is (i) positively charged, (ii) negatively charged ?, Or, Pa Define capacitance of a capacitor. Derive an expression for the, , capacitance of a parallel plate capacitor., , (b) Explain principle of capacitor., , Bt, , 25. Derive an expression for average power of an ac. circuit. How will, , you differentiate between average power and virtual power ?, > Or, Describe briefly the theory of a transformer. Explain copper loss,, iron loss and hysteresis loss in it., 26. Stating the assumptions made and convention of signs used, derive, “the Jens maker’s formula for a thin lens., , Or ds, State Huygens principle. Using this principle, illustrate: how a parallel, , beam of light is reflected from a plane mirror. Prove the laws of, , reflection., , _ XTIKDAR21—5001-C, , 2 -C, , Scanned with CamScanner

Page 5 : Roll No. wi. cetesseeveesserseneereeetsentes, B-1-A oll No. xe, , , , , , , , Total No. of Questions : 26] [Total No. of Printed Pages : 4, , XIIKDAR21, 5001-A, PHYSICS, , Time : 3 Hours] [Maximum Marks : 70, , Section-A 1 each, 1. What is the significance of direction of current ? ed 2, , N, , Why induced e.m.f. is sometimes named as back e.m.f. |2, , 3. Which part of electromagnetic wave is used for viewing. objects, through haze and fog ?, , 4. How does stopping potential vary with intensity of light causing, , photo-electric emission ?, , 5. What is the effect of reverse biasing on the resistance of a p—n, , junction ?, Section-B 2 each, 6. Is any work done by magnetic field on a moving charge ? Explain., Or, How does an ammeter differ from a galvanometer ?, , 4H, 7. Djstinguish between resistance and reactance of an a.c. circuit., , _——, , ss I" ?, , XIIKDAR21—5001-A : Turn Over, , ‘B-1-A, , Scanned with CamScanner