ALLEN. NEET(UG) 2017 TEST PAPER WITH ANSWER & SOLUTIONS (HELD ON SUNDAY 07 th MAY, 2017) 6000Å 3 10 (50)

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1 CODE - X. spring o orce constant k is cut into lengths o ratio : : 3. They are connected in series and ns. () NEET(UG) 07 TEST PPE WTH NSWE & SOLUTONS (HELD ON SUNDY 07 th MY, 07) the new orce constant is k'. Then they are connected in parallel and orce constant is k. Then k' : k is : - () : 9 () : : 4 (4) : 6 Length o the spring segments l, l, l 6 3 s we know K µ l so spring constants or spring segments will be K 6K, K 3K, K 3 K so in parallel combination K" K + K + K 3 K in series combination K' K (s it will become original spring) so K' : K" :. The ratio o resolving powers o an optical ns. () microscope or two wavelengths l 4000 Å and l 6000 Å is :- () 9 : 4 () 3 : 6 : 8 (4) 8 : 7 esolving power µ l P l 6000Å 3 P l 4000Å 3. The two nearest harmonics o a tube closed at one end and open at other end are 0 Hz and 60 Hz. What is the undamental requency o the system? () 0 Hz () 30 Hz 40 Hz (4) 0 Hz ns. () Dierence between any two consecutive requencies v o COP Hz 4l 4. Consider a drop o rain water having mass g alling rom a height o km. t hits the ground with a speed o 50 m/s. Take 'g' constant with a value 0 m/s. The work done by the (i) gravitational orce and the (ii) resistive orce o air is :- () (i).5 J (ii) 8.5 J () (i) 00 J (ii) 8.75 J (i) 0 J (ii) 8.75 J (4) (i) 0 J (ii) 8.5 J ns. Work done by the gravity (W g ) mgh J y work energy theorem W g + W res DKE 0 + W res 0 (50) W res 8.75 J physical quantity o the dimensions o length that can be ormed out o c, G and LLEN e 4pe 0 is [c is velocity o light, G is universal constant o gravitation and e is charge] :- () ns. (4) / é e ù c êg ú () ë 4 pe0 e G c 4pe é e ù [L] [c] a [G] b ê ú ë4pe0 0 c é e ù ê ú c ëg4pe0 é e ù (4) êg ú c ë 4 pe0 [L] [LT ] a [M L 3 T ] b é - c 3 ëml T ù [L] L a+3b+3c M b+c T a b c a + 3b + 3c b + c 0 a + b + c 0 On solving, / / v Þ 0Hz 4l So undamental requency 0 Hz \ L a, b, c é e ù G. ê ú c êë 4 pe0 ú

2 NEET(UG) Two rods and o dierent materials are welded together as shown in igure. Their thermal conductivities are K and K. The thermal conductivity o the composite rod will be :- T T 8. n a common emitter transistor ampliier the audio signal voltage across the collector is 3V. The resistance o collector is 3 kw. current gain is 00 and the base resistance is kw, the voltage and power gain o the ampliier is :- () 5 and 00 () 50 and 5000 d 0 and 000 () 3(K + K ) () K + K (K + K ) (4) ns. (4) K + K n parallel + eq K eq () K K + l l l K eq K + K 7. capacitor is charged by a battery. The battery is ns. () removed and another identical uncharged capacitor is connected in parallel. The total electrostatic energy o resulting system :- () Decreases by a actor o () emains the same ncreases by a actor o (4) ncreases by a actor o 4 Ui CV évù U [C] ê ú Ui ë Decrease by a actor o ns. () (4) 00 and 000 C 3kW V b kw LLEN Power gain b V Thermodynamic processes are indicated in the ns. () ollowing diagram : P Match the ollowing Column- iv 700k 500k 300k V Column- P. Process a. diabatic Q. Process b. sobaric. Process c. sochoric S. Process V d. sothermal () P c, Q a, d, S b () P c, Q d, b, S a P d, Q b, a, S c (4) P a, Q c, d, S b Process () volume constant sochroic Process () adiabatic Process Temperature constant sothermal Process (4) Pressure constant sobaric

3 CODE - X 0. Suppose the charge o a proton and an electron dier slightly. One o them is e, the other is (e + De). the net o electrostatic orce and gravitational orce between two hydrogen atoms placed at a distance d (much greater than atomic size) apart is zero, then De is o the order o [Given mass o hydrogen m h kg] () 0 3 C () 0 37 C 0 47 C (4) 0 0 C ns. () 3. The de-roglie wavelength o a neutron in thermal equilibrium with heavy water at a temperature T (Kelvin) and mass m, is :- () h 3mkT () h 3mkT h h (4) mkt mkt ns. () Kinetic energy o thermal neutron with equilibrium is 3 KT K ( De) Gm r r - G D e m K C. The resistance o a wire is '' ohm. it is melted and stretched to 'n' times its original length, its new resistance will be :- () n ns. () () n n rl! rl Þ µ l volume Þ n C (4) n. The given electrical network is equivalent to : ns. () () O gate () NO gate NOT gate (4) ND gate NO NO NOT y y y y + y y + y y + + y y + NO GTE LLEN Y h h h l mv m K.E æ3 ö m ç KT è ø h 3 mkt 4. Which one o the ollowing represents orward bias diode? ns. (4) () 4V 3V () V +V 3V 5V (4) 0V V V n orward bias V > V Þ only 0V V is in orward bias 5. long solenoid o diameter 0. m has 0 4 turns per meter. t the centre o the solenoid, a coil o 00 turns and radius 0.0 m is placed with its axis coinciding with the solenoid axis. The current in the solenoid reduces at a constant rate to 0 rom 4 in 0.05 s. the resistance o the coil is 0p W. the total charge lowing through the coil during this time is :- () 6 mc () 3 mc 6 p mc (4) 3 p mc ns. () éæd ö ù q êç údt ëè Dt ø é Diù q êm0nnpr ú Dt ë Dt V é æ 4 öù q ê4p p (0 ) ç ú 0.05 ë è.05 ø0p q 3 µc 3

4 NEET(UG) Preeti reached the metro station and ound that the escalator was not working. She walked up the stationary escalator in time t. On other days, i she remains stationary on the moving escalator, then the escalator takes her up in time t. The time taken by her to walk up on the moving escalator will be () ns. () tt t - t () t t (4) V velocity o Preeti V velocity o escalator l distance t V + V tt t + t t + t l tt l l t + t + t t l 7. Young's double slit experment is irst perormed in air and then in a medium other than air. t is ound that 8 th bright ringe in the medium lies where 5 th dark ringe lies in air. The reractive index o the medium is nearly :- ().59 () (4).5 ns. (y 8 ) right, medium (y 5 ) Dark, air 8lmD æ(5) - öld ç d è ø d 8l D 9 ld m d d Þ m beam o light rom a source L is incident normally on a plane mirror ixed at a certain distance x rom the source. The beam is relected back as a spot on a scale placed just above the source. When the mirror is rotated through a small angle q, the spot o the light is ound to move through a distance y on the scale. The angle q is given by :- () y x ns. (4) () x y LLEN x y (4) y x light spot y Source (L) q y x x q ; q y x 9. q and q be the apparent angles o dip observed ns. (4) q in two vertical planes at right angles to each other, then the true angle o dip q is given by :- () tan q tan q + tan q () cot q cot q cot q tan q tan q tan q (4) cot q cot q + cot q tanq Þ tanq tanq cos a Þ sin a + cos a tanq tanq cos(90 a) sin a Þ cot q + cot q cot q 0. Tow cars moving in opposite directions approach ns. each other with speed o m/s and 6.5 m/s respectively. The driver o the irst car blows a horn having a a requency 400 Hz. The requency heard by the driver o the second car is [velocity o sound 340 m/s] :- () 36 Hz () 4 Hz 448 Hz (4) 350 Hz v m/s s 400 Hz 0 v o 6.5 m/s s we know or given condition æv + vobserver ö ç è v - vsource ø app 0 app 448 Hz æ ö 400ç è ø 4

5 CODE - X. Two blocks and o masses 3 m and m respectively are connected by a massless and inextensible string. The whole system is suspended by a massless spring as shown in igure. The magnitudes o acceleration o and immediately ater the string is cut, are respectively :- 3. The acceleration due to gravity at a height km above the earth is the same as at a depth d below the surace o earth. Then :- () d km () d 3 km d km (4) d km () g,g 3 3m m () g,g g, g 3 3 ns. () eore cutting the strip :- 4mg T 3mg T \ T mg ter cutting the strip :- 4mg a a 3mg 4mg -3mg g 3m 3 mg g m mg mg (4) g g 3. thin prism having reracting angle 0 is made o glass o reractive index.4. This prism is combined with another thin prism o glass o reractive index.7. This combination produces dispersion without deviation. The reracting angle o second prism should be :- () 6 () 8 0 (4) 4 ns. () For dispersion without deviation d d (m ) (m ) 0(.4 ) (.7 ) 6 ns. Q g h g d æ hö æ d ö gç - gç - è ø è ø d h km 4. potentiometer is an accurate and versatile device to make electrical measurements o E.M.F. because the method involves :- ns. () () Potential gradients () condition o no current low through the galvanometer combination o cells, galvanometer and resistances (4) Cells n zero delection condition, potentiometer draws no current. LLEN 5. spherical black body with a radius o cm radiates 450 watt power at 500 K. the radius were halved and the temperature doubled, the power radiated in watt would be :- ns. () 450 () (4) 5 P µ r T 4 Þ P P 4 ær ö æ T ö ç ç èr ø è T ø P 800 watt 5

6 NEET(UG) Figure shows a circuit that contains three identical resistors with resistance 9.0 W each, two identical inductors with inductance L.0 mh each, and an ideal battery with em e 8 V. The current 'i' through the battery just ater the switch closed is,... :- + e L () 0. () 0 ampere (4) m ns. (onus) at t 0 i i i i e e 8 9 \ Current through the battery is i i 4 (onus) O ccording to question language : Capacitor is not mentioned so i 7. adioactive material '' has decay constant '8 l' and material '' has decay constant 'l'. nitially they have same number o nuclei. ter what time, the ratio o number o nuclei o material '' to that '' will be e? () 7l () ns. () l 8 l, l l Þ N 8l L C LLEN N e Þ N 0 e lt 9l N0 e e -8lt (4) l 8. The diagrams below show regions o equipotentials:- 0V 40V 0V 30V ns. () 0V 40V 0V 30V 0V 0V 30V 40V 40V 0V 0V 30V (a) (b) (c) (d) positive charge is moved rom to in each diagram. () n all the our cases the work done is the same () Minimum work is required to move q in igure (a) Maximum work is required to move q in igure (b) (4) Maximum work is required to move q in igure (c) W qdv as DV is same in all conditions, work will be same. 9. Two astronauts are loating in gravitational ree space ater having lost contact with their spaceship. The two will :- ns. () () Move towards each other. () Move away rom each other. Will become stationary (4) Keep loating at the same distance between them. stronauts move towards each other under mutual gravitational orce. 30. The x and y coordinates o the particle at any time are x 5t t and y 0t respectively, where x and y are in meters and t in seconds. The acceleration o the particle at t s is :- ns. () () 5 m/s () 4 m/s 8 m/s (4) 0 Þ lt 8lt Þ 7lt Þ t - 7 l est answer is t 7l v x 5 4t, v y 0 a x 4, a y 0 r a ai ˆ+ aj ˆ x a -4i ˆm/s y r 6

7 CODE - X 3. One end o string o length l is connected to a particle o mass 'm' and the other end is connected to a small peg on a smooth horizontal table. the particle moves in circle with speed 'v' the net orce on the particle (directed towards centre) will be (T represents the tension in the string) :- mv () T + l mv () T - l Zero (4) T ns. (4) Net orce on the particle in uniorm circular motion is centripetal orce, which is provided by the tension in string. 3. particle executes linear simple harmonic motion with an amplitude o 3 cm. When the particle is at cm rom the mean position, the magnitude o its velocity is equal to that o its acceleration. Then its time period in seconds is :- () 5 p () 4p 5 p ns. () mplitude 3 cm When particle is at x cm, its velocity acceleration 3 (4) 5 p i.e., w -x -x w x Þ w x p æ ö 4p T w p ç è 5 ø Two Polaroids P and P are placed with their axis perpendicular to each other. Unpolarised light 0 is incident on P. third polaroid P 3 is kept in between P and P such that its axis makes an angle 45 with that o P. The intensity o transmitted light through P is :- ns. () () 0 4 () 0 8 P P 3 LLEN 0 6 (4) P 3 cos cos The bulk modulus o a spherical object is ''. it is subjected to uniorm pressure 'p', the ractional decrease in radius is :- ns. () 3p DP DV - V DP Þ - 3 D () 3p, D V 3 D V D P - 3 p 3 (DP P) (4) p 35. n an electromagnetic wave in ree space the root mean square value o the electric ield is E rms 6V/m. The peak value o the magnetic ield is :- () T () T T (4) T ns. () E 0 C 0 E E rms 0 Þ E C Þ rms 0 Erms 6 C T rope is wound around a hollow cylinder o mass 3 kg and radius 40 cm. What is the angular acceleration o the cylinder i the rope is pulled with a orce o 30 N? () 0.5 rad/s () 5 rad/s 5 m/s (4) 5 m/s ns. () t a F m a 30 N 0 45 a F 30 m 5 rad/s

8 NEET(UG) Two discs o same moment o inertia rotating about their regular axis passing through centre and perpendicular to the plane o disc with angular velocities w and w. They are brought into contact ace to ace coinciding the axis o rotation. The expression or loss o energy during this process is:- ns. () 4 w -w () ( ) 8 w -w ( ) COM : () ( ) w -w w +w (4) ( ) w +w w + w wþw (K.E.) i w + w æw +w ö (K.E.) w ç è ø Loss in K.E. (K.E.) i (K.E) ( w -w ) The photoelectric threshold wavelength o silver is m. The velocity o the electron ejected rom a silver surace by ultraviolet light o wavelength m is :- (Given h evs and c ms ) ()» ms ()» ms» ms (4)» ms ns. ( or 4) l Å l 536 Å é ù mv hc ê - l l ú ë 0 v hc m é ù ê - l l ú ë 0 LLEN é 74 ù -3 ê 9. 0 ë ú m/s m/s Turn rectangular coil o length. cm and width.5 cm carries a current o 85 µ and subjected to magnetic ield o strength 0.85 T. Work done or rotating the coil by 80º against the torque is:- ns. (4) () 4.55 µj ().3 µj.5 µ J (4) 9. µ J Work M[cos q cos q ] Work M[cos 0 cos 80 ] W Ni[ ( )] W ; 9. µj 40. The ratio o wavelengths o the last line o almer series and the last line o Lyman series is :- ns. () () () (4) For last line o almer : n & n é ù é ù Z - () ê - l ú êën nú ë 4 l...() For last line o Lyman series : n & n é ù é ù Z - () ê - l ú L êën nú ë l L /...() l (4/) 4 l (/ ) L 4. carnot engine having an eiciency o 0 ns. () as heat engine, is used as a rerigerator. the work done on the system is 0 J, the amount o energy absorbed rom the reservoir at lower temperature is :- () 90 J () 99 J 00 J (4) J b Q -h W h Þ Q Þ Q J 8

9 CODE - X 4. gas mixture consists o moles o O and 4 moles o r at temperature T. Neglecting all vibrational modes, the total internal energy o the system is :- ns. () 5 T () 9 T T (4) 4 T U nt 5 3 U total ()T + (4)T U total T 43. n arrangement o three parallel straight wires placed perpendicular to plane o paper carrying same current ' along the same direction is shown in ig. Magnitude o orce per unit length on the middle wire '' is given by :- () ns. m0i pd m0i pd m ii F pd F 0 d d 90 () C m0i pd LLEN (4) m 0i pd orce per unit length ( m i) i m i 0 0 pd pd F F [due to wire ] 44. U tube with both ends open to the atmosphere, is partially illed with water. Oil, which is immiscible with water, is poured into one side until it stands at a distance o 0 mm above the water level on the other side. Meanwhile the water rises by 65 mm rom its original level (see diagram). The density o the oil is :- ns. Oil Pa 65 mm D 65 mm F E Pa 0 mm Final water level nitial water level C Water () 45 kg m 3 () 800 kg m 3 98 kg m 3 (4) 650 kg m 3 r 0 g r w g r 0 0» 98 kg/m Which o the ollowing statements are correct? (a) (b) (c) (d) ns. (4) Centre o mass o a body always coincides with the centre o gravity o the body Central o mass o a body is the point at which the total gravitational torque on the body is zero couple on a body produce both translational and rotation motion in a body Mechanical advantage greater than one means that small eort can be used to lit a large load () (a) and (b) () (b) and (c) (c) and (d) (4) (b) and (d) Centre o mass may lie on centre o gravity net torque o gravitational pull is zero about centre o mass. F [due to wire C] i 0 F + net F F m pd Mechanical advantage Load Eort > Þ Load > Eort 9

PHYSICS. [Time 3 hours] [Maximum Marks: 720]

PHYSICS. [Time 3 hours] [Maximum Marks: 720] CBSE MAINS-07 PHYSICS [Time 3 hours] [Maximum Marks: 70] General Instructions:. The Answer Sheet is inside this Test Booklet. When you are directed to open the Test Booklet, take out the Answer Sheet and