ShOTION ~ a the vertions A and B of an equilaters! Two ohare —9 onch are pioeee o a trianato ARI NOW Whe taldepetne AR ornare Seguin a point along A) OA (o) Me ™ oe A student has ih . A guden Shee Tosimors, each of resiance R. To oinain #-aesinance of 3 Ry she should connect (A) all the A all the (©) Wo resistors ye third pes: DP) two Pesisto third resistor. rent of a conductor carrying 2 A current in x direction ly at origin of C field due to this segment at Point (1m, 1m, 0) is A) 10x 10-98 p ® -10x10° kT (0) Yen 1orek r ® -Sx1wekt 4. The magnetic field ai _— * dcance tom the oir aay re a (a) #2, 2M % M an 8 ® 2.4 4o M Ho 2M © ons o 2.2 5. In the figure X is a coil wound over a hollow wooden pipe. i x Y Zz A permanent magnet is pushed at a constant speed v from the right into the pipe and it comes out at the left end of the pipe. During the entry and the exit of the magnet, the current in the wire YZ will be from (A) YtoZand then Y toZ (®) ZtoY and then ¥toZ (©) YtoZand then Z to Y @) ZtoY and then Zto¥ on Page 5 of 24 Pa @ scanned with OKEN Scanner-_ ‘The alternating er F od 8 raph font Lin an inductor is observed to vary with time tas f | 55/2/1 Page 7 of 24 shown in the graph fory coe 1 't 0 Which one of the foll een - form of voltage V with tia (raphe is the correct representation of wave © HH: ©) LT tTRyF A transformer is connected to a 200 V i s ac source. The transformer supplies 3000 V to a device. If the number of turns in the primary coil is 450, then 1 the number of turns in its second, coil is ~ (A) 30 “"(B) 450 (©) 4500 (D) 6750 Which one of the following statements is correct ? Electric field due to static charges is 1 (A) conservative and field lines do not form closed loops. (B) conservative and field lines form closed loops. (C) non-conservative and field lines do not form closed loops. (D) non-conservative and field lines form closed loops. A tub is filled with a transparent liquid to a height of 30.0 cm. The apparent depth of a coin lying at the bottom of the tub is found to be 16.0 cm. The speed of light in the liquid will be a A) 16x 108mst (@) 2.0x108mst (©) 3.0x 108ms @) 25x 108mst Atomic spectral emission lines of hydrogen atom are incident on a zine surface. The lines which can emit photoelectrons from the surface are i members of (A) Balmer series (B) Paschen series (©) Lyman series ' (D) Neither Balmer, nor Paschen nor Lyman series P.T.O. | a @ scanned with OKEN Scannerenergy of an the electron in a hydrogen atom in ground state is 13.6 eV. 11. energy in an orbj He eras of nig StPesbonding to quantum number nis -0.544 eV. 2 1 “ e Bi j2, When the resistance f 2. ode is high, it can rarer between p and n ends of a p-n junction (A) resistor - 1 (©) capacitor (B) inductor () switch estions 18 to 16, For other labelled Reason {tatements are given ~ one labelled Assertion (A) and te codes (A), B) (Ona ee the comet answer to these questions fiom it both Assertion as given below : @ explanation of eee (R) are true and Reason (R) is the correct If both Asserti . © correct explanation oyna Reason (R) are true but Reason (R) is not the ; i sertion (A). OTe both han ape acon (Ri fale (D) Ifboth Assertion (A) and Reason (R) are false. Assertio! is 5 13 n (A) : In a semiconductor diode the thickness of depletion layer is not fixed. f Reason : Thi 4 (R) + Thickness’of depletion layer in a semiconductor device depends upon many factors such as biasing of the semiconductor. In Bohr model of hydrogen atom, the angular momentum of an electron in n' orbit is proportional to the square root of its orbit radius r,,. 1 According to Bohr model, electron can jump to its nearest orbits only. Out of Infrared and radio waves, the radio waves show u more diffraction effect. Radio waves have greater frequency than infrared 4, Assertion (A) : Reason (R) Assertion (A) : Reason (R) : waves. Assertion (A) : In an ideal step-down transformer, the electrical energy is not lost. i Reason (R) : Ina step-down transformer, voltage decreases but the current increases. Page 9 of 24 P.T.O. | 2/1 f @ scanned with OKEN Scanner: SECTION -B 1. @ To wi « wites of the same material and the same radius have their 1 i : — in the ratio 2: 3, They are connected in parallel to a battery Supplies a current of 15 A, Find the current through the wires, oR o) In the circuit three ideal cells of e.m.f. V, Vand 2V are connected to a Resistor ce resistance Ry a capacitor of capacitance C and another oo of resistance 2R as shown in figure. In the steady state find Mere, Potential difference between P and Q and Gi) potential ence across capacitor C, 4 R 7, c Prft-—{F—4a av, 2R 1 S._ Ina double-slit experiment, 6 dark fringe is observed at a certain point of the screen. A transparent sheet of thickness t and refractive index n is now introduced in the path of one of the two interfering waves to increase its phase by 2x (n~ 1) WA. The pattern is shifted and 8% bright fringe is observed at the same point, Find the relation for thickness t in terms of n and A. 2 19. Two concave lenses A and B, each of focal length 8.0 cm are arranged coaxially 16 cm apart as shown in figure. An object P is placed at a distance of 4.0 cm from A. Find the position and nature of the final image 2 Se A light of wavelength 400 nm is incident on metal surface whose work function is 3.0x 10-19 J. Calculate the speed of the fastest photoelectrons emitted. .2]. The threshold voltage of a silicon diode is 0.7 V. It is operated at this point by connecting the diode in series with a battery of V volt and a resistor of 1000 Q. Find the value of V when the current drawn is 15 mA. 2 SECTION - C 22. (a) A cell of e.m/f. E and internal resistance r is connected with a variable external resistance R and a voltmeter showing potential drop Vacross R. Obtain the relationship between V, E, R and r. 3 (e) Draw the shape of the graph showing the variation of terminal voltage V of the cell as a function of current I drawn from it. How one can determine the e.m of the cell and its internal resistance from this graph ? Page 11 of 24 P.T.O. ] | 55/2/1 @ scanned with OKEN Scanner(b) (a) mA. (b) 25. (a) ) © 26. (a) (b) (© | 55/2/1 In a region is moving oo electric fed £, 0 negatively charged particle conti cola * constant velocity 7 = —y,} near a lone straight axis. The partayint "ith XX axis and carrying current I towards -—X @) Draw diagr Temains at a distance d from the conductor. 8 Gi) What are ta 22 Wing direction of electric and ma — Gil) Find the vnf,Y2%10u8 forces acting on the charged particle? Value of v, in terme of Ed and 1. Two infini OR crepe long conductors kept along XX’ and YY asco se Find the czzent Ly and 1, along -X axis and -Y axis respectively at pole Poe and direction of the net magnetic field produced State Lenz’s law. 3 In the given figure - a Identify the machine. ; (ii) Name the parts P and Q and R of the machine. (ii) Give the polarities of the magnetic poles. tput voltage. (iv) Write the two ways of increasing the out ‘The electric field Hf of an electromagnetic wave propagating in north direction is oscillating in up and down direction. Describe the direction of magnetic field B of the wave. 3 ‘Are the wave length of radio waves and microwaves longer or shorter than those detectable by human eyes ? Write main use of each of the following in human life : (i) Infrared waves (i) Gamma rays When a parallel beam of light enters water surface obliquely at some angle, what is the effect on the width of the beam ? 3 fray diagram, show that a straw appears bent With the help of hat when it is partly dipped in water and explain it. Explain the transmission of optical signal through an optical fibre by a diagram. Page 18 of 24 P.T.O. I 4 © scanned with OKEN Scanner7 @ Show the var ; ©) Two uct si) T2™AIne unch, am é Git) DooZins unchanged 7% Of nuclei increases, decreases or 28. () Wh # the procews r ; at are majority and mi in wy) Semiconductor 7 P-n junction j, 6 fo ; charge carrier, whisper biased. Describe the movement of the ch produce current in it. © The <3€ Braph shows r junetion diode” "P® Variation of current with voltage for a p-n nergy or produce energy ? jority charge carriers in an extrinsic I (mA) “Ly rf -L2 -10-08-06-04-02 0 02 04 06 08 s V (volts) Estimate the dynamic resistance of diode at V = -0.6 volt. SECTION -D Question numbers 29 and 30 are case study based questions. Read the 7 following paragraphs-and answer the questions that follow. 29. A parallel plate capacitor has two parallel plates which are separated by an insulating medium like air, mica, etc. When the plates are connected to the terminals of a battery, they get equal and opposite charges and an electric field is set up in between them. This electric field between the two plates depends upon the potential difference applied, the separation of the plates and nature of the medium between the plates. 4x1=4 (i) The electric field between the plates of a parallel plate capacitor is B. Now the separation between the plates is doubled and simultaneously the applied potential difference between the plates is reduced to half of its initial value. The new value of the electric field between the plates will be : (A) E ® 2 E Zz OF ©) 9 I 55/2/1 Page 15 of 24 ram 4 i @ scanned with OKEN Scannerx, Gi) Gy) | 55/2/1 & Capacitor wh, IS to by eraphs correctio | S°Patation @8intained between the plored Pict the no ch between the two plates of the plates as a atte Potential ain ime. Which ‘ot ‘the 0 be applic ‘0 maintain the co neti ; re ion of “@ , tant electric ppeBeration betweon he ola a 2 ®) ¥ a © @) a In the above An” Plate G00", figure P, Q are the two parallel plates of a capacitor. imaginary j4,Positive potential with respect to plate P. MN is an graphs ; one drawa Perpendicular to the plates. Which of ree , ; a ield strength Baus A ie variations of the magnitude of elec @ a @t ol oi)\_/ ew oe Three parallel plates are placed above each other with equal displacement d between neighbouring plates. The electric field between the first pair of the plates is z, and the electric field between the second pair of the plates is E». The potential difference between the third and the first plate is — > i oe + oe (A) &,+E)-d ® &,-E,)-d A , a+ ED (© &,-#,)-d OR Page 17 of 24 P.T.O. l @ scanned with OKEN Scannera A material of diclects: : lect @ capacitor of capacitance ¢ constant Kj, i 8 filled i Phe ac SW Value of ts cana ge stalled plate (B) g Pacitance becomes ©) 42 yhen @ photon r 143) 30. protoelectron i Si pee frequency ® mae, is inci frequency (v,) for the gu; ae it. Tf the tegusaa? on a metal surface, frequency v(v > y,), ¢ ‘ce, No photoelectro lency is below a threshold . the kinetic energy ot n is emitted. For a photon of aide Rais be the emitted photoelectrons is hotel Ping Potential’ stopped by applying a potential V photoelectrons K, = eV. =} the anode, Thus maximum kinetic energy of and v for a metal ia shox) = h(v — y,). The experimental graph between V, n in figure. This is a straight line of slope m. 4x 1= 4 (i) The straight line graphs obtained for two metals (A) coincide each other. (B) are parallel to each other. (C) are not parallel to each other and cross at @ point on y-axis. (D) are not parallel to each other and do not cross at a point on v-axis. (ii) The value of Planck’s constant for this metal is as ® ae (©) me oe The intercepts on v-axis and V,-axis of the graph are respectively : hy, A). e97ge (B) v,,hy, hy, © saab @) by, % OR Page 19 of 24 P.T.O. | @ scanned with OKEN ScannerGi). When the wavelen; th of a photon is doubled, how many times i wave number and frequency become, respectively? 1 @ 23 ® 33 2 © x @) 2,2 (Gv) The _momentum of a photon is 5.0 x 10 kg. m/s. Ignoring relativistic effects (if any), the wavelength of the photon is (A) 1.33 ym ®) 33ym © 166um ©) 13.3 um SECTION - E (@) @ A small conducting sphere A of radius r charged to a potential V, is enclosed by a spherical conducting shell'B of radius R. If A and B are connected by a thin wire, calculate the final potential on sphere A and shell B. 5 (i) Write two characteristics of equipotential surfaces. A uniform electric field of 50 NC-? is set up in a region along +x axis. If the potential at the origin (0, 0) is 220 V, find the potential at a point (4m, 3m). OR What is difference between an open surface and a closed surface ? ® @ Draw elementary surface vector dS for a spherical surface S. Gi) Define electric flux through a surface. Give the significance of 2 Gaussian surface. A charge outside a Gaussian surface does not contribute to total electric flux through the surface. Why ? ii) A small spherical shell S, has point charges q, =—3 #C, d= —2 uC and q, = 9 uC inside it. This shell is enclosed by another big spherical shell S.. A point charge Q is placed in between the two surfaces S, and S,. If the electric flux through the surface S, is four times the flux through surface S,, find charge Q. tt is the source of force acting on a current-carrying 1d ? Obtain the expression for What conductor placed in a magnetic fiel _ force cate between two long straight parallel conductors i carrying steady currents and hence define ‘ampere’. J Page 21 of 24 PT. ‘| @ scanned with OKEN ScannerGi) A Point charge magneti =, 1 18 moving with velocity ¥ in a uniform Snetic field B. Find th nee © work (iii) Explain the ne charged Particl done by the magnetic force on “essary conditions in which the trajectory of a le is es in a uniform magnetic field. © @ Acurrent ca is tying loop can be considere: otic dipole Placed alone P can be considered as a magnetic dipol its axis, Explain, Gi) Obtai ; ‘ain the relation for magnetic dipole moment M of current carry: 71 5 iy A ‘ying coil. Give the direction of M. current carrying coil ig Placed in an external uniform Wont ia the a za coil is free to turn in the magnetic field. of the coil in stable tine 00 the coil ? Obtain the orientation oP cable equilibrium, Show that in thie orientation the flux of the total field field produced by the loop + external field) through the coil is asin, a A thin pencil of ) Principal axis of a 33. i oe) length (f/4) is placed coinciding with the ae mirror of focal length f. The image of the renal 3s real and enlarged, just touches the pencil. Calculate i) 2 « magnification produced by the mirror. . . ray of light is incident on a refracting face AB of a prism ABC at an angle of 45°. The ray emerges from face AC and the angle of deviation is 15°, The angle of prism is 30°. Show that the emergent ray is normal to the face AC from which it emerges out. Find the refraction index of the material of the prism. OR (©) (@ Light consisting of two wavelengths 600 nm and 480 nm is used to obtain interference fringes in a double slit experiment. The screen is placed 1.0 m away from slits which are 1.0 nm apart. (1) Calculate the distance of the third bright fringe on the screen from the central maximum for wavelength 600 nm. (2) Find the least distance from the central maximum where the bright fringes due to both the wavelengths coincide. Gi) (1) Draw the variation of intensity with angle of diffraction in single slit diffraction pattern. Write the expression for value of angle corresponding to zero intensity locations. (2) In what way diffraction of light waves differs from diffraction of sound waves ? 55/2/1 Page 23 of 24 | @ scanned with OKEN Scanner