cet physics full
Transcription
cet physics full
KOTA ACADEMY RAMKUNJ, SAHYADRI HOUSING SOCIETY, SHANIWAR PETH, KARAD 9423866425 MH-CET / JEE / JEE - Adv. / AIPMT Date : Time : 00:45:00Mins Marks : 50 1. 2. 3. 4. 5. 6. 7. 8. The work done by the centripetal force in quarter revolution would be, a) infinity b) increases c) zero d) decreases In half period of revolution displacement and the distance covered is: a) 2r , πr b) πr, 2r c) 2 πr,2r d) zero, 2 πr A ball of mass 0.5kg and diameter 8cm rotates in a horizontal circle at the end of a string of 1.96 m long. The tension in the string, when the speed of rotation is 10 revolution in 2 sec. will be a) 785 N b) 986 N c) 585 N d) 685 N 24 The earth (mass =6.10 kg) revolves round the sun with an angular velocity of 2×10-7 rad/s in a circular orbit of radius 1.5 ×108 km in a circular orbit of radius 1.5×108 km the gravitational force exerted by the sun in the earth, in Newton, is a) Zero b) 18×1025 c) 36×1021 d) 3.6×1018 Gravitational force between two bodies exists a) When they are in contact only b) When they are not in contact only c) Any of the above two cases d) Can not be predicted A cylinder full of water is rotating about its own axis with uniform angular velocity Then the shape of free surface of water will be a) parabola b) elliptical c) circular d) spherical M.I. of a uniform disc about a central axis is 1 kgm2. It is rotating with an angular velocity of 100 rad/sec. Another identical disc is gently placed on it so that their centre coincides now these two move together with the same axis the loss in K.E. of rotation will be in joules: a) 2.5 kJ b) 3.0 kJ c) 3.5 kJ d) 4.0 kJ AB is a stick half of which is wood and the other half steel. IA is moment of inertia about an axis TEST ID: 24 PHYSICS passing through A and perpendicular to the length. IB is moment of inertia about an axis passing through B and perpendicular to the length Then 9. a) IA = IB b) IA > IB c) IB > IA d) we cannot say A simple pendulum is suspended from roof of lift. If lift moves downward with acceleration a then period of pendulum T = 2 π 10. 11. 12. 13. 14. 𝑙 g then g' will be: a) g + a b) g - a 2 2 d) g c) 𝑔 + 𝑎 If the rope of the lift breaks , time period of suspended pendulum in a lift is a) zero b) abrupt by increases c) abrupt by decreases d) infinite The displacement of a particle performing S.H.M. is given by x = 10 sin (𝜔𝑡 + 𝛼 ) metre. If the displacement of the particle is 5 m, then the phase of S.H.M. is 𝜋 𝜋 a) radian b) radian 3 6 𝜋 𝜋 c) radian d) radian 4 2 The spring balance shows wrong readings after they have been used for a long time because a) of extension in the spring decreases b) of extension in the spring is more c) of the spring looses elastic property and becomes plastic d) of lack of internal elastic forces A wire of length L, radius r when stretched with a force F changes the length by ℓ. What will be the change in length of a wire of same material having length 2L, radius 2r and stretched by a force 2F? a) ℓ /2 b) ℓ c) 2 ℓ d) 4 ℓ Two soap bubbles of different radii are in Page|1 15. 16. 17. 18. 19. 20. communication with each other. : a) Air flows from the larger bubble into the smal1er one until the two bubbles are of equal size b) The size of the bubbles remains the same. c) Air flows from smaller bubble into the larger one and the larger bubble grows at the expense of the smaller one d) Air flows from larger bubble into the smal1er one and the smal1er bubble grows at the expense of the larger one If two soap bubbles of unequal radii are in communication with each other , then a) air flows from the larger bubbles into smaller bubble until they have the same size b) the size of the bubbles remains the same c) air flow from smaller bubbles into larger bubble and the larger bubble grows in size and the size of the smaller bubble decreases. d) air may flow from the smaller bubble into the larger bubble or from the lager bubble into the smaller bubble depending upon the concentration of the soap solution A drop of water splits up into 64 droplets each of equal radius of 1 mm. The original droplet is having a diameter of: a) 2 mm b) 4 mm c) 64 mm d) 128 mm The prongs of the tuning fork are filled a little, the frequency of the tuning fork after filled a) increases b) remains constant c) decreases d) cannot be predicated The equation of a sound wave is y = 0.0015 sin (62.8 x + 316 t). Find the wavelength of this wave: a) 0.2 unit b) 0.1 unit c) 0.3 unit d) 0.4 unit When longitudinal stationary waves are produced in a medium, then the physical characteristics changes at antinode is / are a) density only b) density and pressure c) pressure only d) neither density nor pressure A tuning fork of frequency of resonants with a closed organ pipe when the length of the shortest air columns are a & b respectively The speed of sound in air is: f b−a a) f (a - b) b) 2 c) 2V (b + a) d) 2f (b - a) 21. Velocity of a particle in stationary wave is maximum at a) antinode b) node c) mid way between node and antinode d) can not be predicted 22. Rice takes longest time to cook: a) at the sea level b) in srinager c) at mount Everest d) in submarine 100 m below the surface of sea 23. The luminousity of a star is10000 times that of the sun. If the surface temperature of the sun is 6000 K, then the surface temperature of the star is a) 8446 K b) 84860 K c) 848600 K d) 60,000 K 24. The average velocity of the gas molecules in a gas in equilibrium is a) proportional to square root of temperature b) proportional to temperature c) proportional to square of temperature d) equal to zero 25. The radius of curvature of a plane wavefront a) is less than that of a spherical wavefront b) is infinity c) is equal to the radius of curvature of a reversing wavefront d) is slightly more than that of a cylindrical wavefront 26. According to Huygen's construction which of the following wavefront does not exists? a) forward wavefront b) backward wavefront c) cylindrical wavefront d) can not be predicted 27. In which of the following coloured light limit of resolution is more : a) Red b) Green c) Yellow d) Violet 28. Biprism experiment is conducted with a wavelength of 5000 Å. The distance between the Virtual sources is 0.2 mm and the micrometer eyepiece is at a distance of 100 cm from the slits. The distance between the consecutive bright and dark band is a) 1.25 mm b) 2.5 mm c) 3.5 mm d) 0.25 mm 29. Two capacitors of capacitances 10 F and 20 F are connected in series across a potential difference of 100V. The potential difference across each condenser is respectively a) 66.67 V, 33.33 V b) 60 V, 40 V Page|2 30. 31. 32. 33. 34. 35. 36. 37. c) 50 V, 50 V d) 90 V, 10 V A dielectric is introduced between thy elements of the condenser kept at a constant potential difference. Then the charge on condenser a) Decrease b) increase c) remains unchanged d) may increase or decrease A potentiometer wire is 10 m long and has a resistance of 2 Ω/m. It is connected in series with a battery of e. m. f. 3 V and a resistance of 10 Ω. The potential gradient along the wire in V/m is a) 0.01 b) 0.02 c) 0.1 d) 0.2 The internal resistance of an ideal cell is a) Zero b) 1 ohm c) 2 ohm d) Infinity When a number of thermocouple are joined in series, the thermo e. m. f. a) Decreases b) Increases c) Becomes zero d) Remains same. A proton is to circulate the earth along the equator with a speed of 1 × 107 m/s. The minimum magnetic field which should be created at the equator for this purpose will be (mp = 1.7 × 10-27 kg and r = 6.37 × 106m) a) 1.6 × 10-8 T b) 2.6 × 10-8 T c) 3.6 × 10-8 T d) 4.6 × 10-8 T The coil of a galvanometer consists of 100 turns and effective area of 1 square cm. The restoring couple is 10-8 N-m/radian. The magnetic field between the pole pieces is 5T. The current sensitivity of this galvanometer will be (a) p (8) (c) (d) 1oq,i a) 5 × 104 rad/ µamp b) 5 × 10-6 rad/ amp c) 2 × 10-7 rad/ amp d) 5 rad/ µamp A galvanometer of resistance 25 Ω is shunted by 2.5 Ω resistance. The part (fraction) of the total current that flows through the galvanometer is given as IG 1 IG 2 a) = b) = I0 11 I0 11 IG 3 IG 4 c) = d) = I0 11 I0 11 In hydrogen atom the electrons revolves around the nucleus 6.8× 1015 times per second in an orbit of radius 0.53A. Determine its equivalent magnetic moment(e = 1.6 × 10−19 C) a) 9.1 × 10−24 Am2 b) 9.3 × 10−24 Am2 −24 2 c) 9.0 × 10 Am d) 9.6 × 10−24 Am2 38. Curie temperature is particular temperature at which ferromagnetic material changes to a) Diamagnetic b) Nonmagnetic c) Paramagnetic d) Antimagnetic 39. An L.C. circuit contains 10 mH inductor and a 2.5μF capacitor the resistance of the circuit is negligible. The energy stored in the circuit is completely magnetic at time (in milli seconds)being measured from the instant when the circuit is closed a) 1.57,4.71,7.85 b) 1.57,3.14,4.17 c) 0,1.57,4.71 d) 15.7,47.1,78.5 40. A voltmeter reads V volts in an A.C. circuit then V is a) peak value of the voltage b) peak value of the current c) r.m.s. value of the current d) r.m.s. value of the voltage 41. In circuit shown in figure what will be the reading of a voltmeter and ammeter if a.c. source of 220 V and 100 Hz is connected? a) 220 V, 2 A b) 300 V, 2A c) 220 V, 2.2A d) 300 V, 2.2 A 42. The work function for photoelectric effect a) depends upon the frequency of incident light b) is same for all metals c) is different for different metals d) none of these 43. ln photoelectric effect, the number of photoelectrons emitted is proportional to a) intensity of incident beam b) frequency of incident beam c) velocity of incident beam d) none of these 44. If the kinetic energy associated with an electron is doubled, then its de Broglie wavelength changes by the factor a) 2 b) 1/2 c) 2 d) 1 / 2 45. The ratio of the frequencies of the long wavelength limits of Lyman and Balmer series of hydrogen is: a) 4: 1 b) 1: 4 Page|3 c) 27: 5 d) 5: 27 46. LASER is and acronym of: a) Light Analysis of Spontaneous Emission of Radiation b) Light Amplification of Spontaneous Emission of Radiation c) Light Amplification by Stimulated Emission of a) 2A b) 1A Radiation c) 0.5A d) 0.25A d) Light Analysis by Stimulated Emission of 49. Sky wave propagation is called as shortwave Radiation. band (SW) used in: 47. In a half wave rectifier, the r.m.s. value of the a.c. a) Radio communication component of the wave is b) T.V. communication a) equal to d.c. value b) more than d.c. value. c) Satellite communication c) less than d.c. value. d) zero. d) Satellite and T.V. communication 48. Current through the battery in the given figure: 50. In the process of modulation , the signals whose characteristic is changed according to modulating signals is called as : a) Modulated signals b) Analog signals c) Digital signals d) Modulating signals Page|4 KOTA ACADEMY RAMKUNJ, SAHYADRI HOUSING SOCIETY, SHANIWAR PETH, KARAD 9423866425 MH-CET / JEE / JEE - Adv. / AIPMT Date : Time : 00:45:00Mins Marks : 50 TEST ID: 24 PHYSICS : ANSWER KEY : 1) 5) 9) 13) 17) 21) 25) c b b b a a b 2) 6) 10) 14) 18) 22) 26) a a d c b c b 3) 7) 11) 15) 19) 23) 27) b a b c b d a 4) 8) 12) 16) 20) 24) 28) c b b b d a a 29) 33) 37) 41) 45) 49) a b d c c a 30) 34) 38) 42) 46) 50) b a c c c a 31) 35) 39) 43) 47) d d a a d 32) 36) 40) 44) 48) a a d d c Page|5 KOTA ACADEMY RAMKUNJ, SAHYADRI HOUSING SOCIETY, SHANIWAR PETH, KARAD 9423866425 MH-CET / JEE / JEE - Adv. / AIPMT Date : Time : 00:45:00Mins Marks : 50 TEST ID: 24 PHYSICS : HINTS AND SOLUTIONS : 1 (c) ω=F.S=F S cos 90=F S x 0=0 3 (b) F = mrω2 = mr 2πn 2 Here r = 1.96 + 0.04 =2m F = 0.5 × 2 × 2× π×5 2= 1× 10π 2 = 100 π2 = 100 × 9.86= 986N 4 (c) F=mrω2 6 (a) 28 2 Because difference in centrifugal force (F = mr which is propontional to r) 29 7 (a) Common ang. speed after coupling I1 1 + I2 2 1 (1000) = = = 50 rad/sec I1 + I2 2 Loss of K.E. = K.E. initial – K.E. final = 2.5 kJ 31 11 (b) x = 5 = 10 sin ωt+α 1 ⇒2= sin ωt+α 𝜋 ∴ sin ωt+α = sin6 𝜋 ⇒ ωt+α =6 13 (b) F L Y= × ℓ = extension A ℓ Y1 = Y2 F1 L1 F2 L2 FL 2F × 2L = ⇒ 2= ⇒ ℓ = ℓ A1 ℓ1 A2 ℓ2 πr 4πr 2 × ℓ 16 (b) Volume of n droplet = volume of single drop R3 = 64 r3 R = 4mm 18 (b) 𝑘 = 62.8 𝑢𝑛𝑖𝑡 2π 2π k= ⇒λ= λ k 2×3.14 = =0.1 unit 62.8 23 (d) 34 35 P1 = I1 A1 and P2 = I2 A2 But P1 = σ A1T41 and P2 = σ A1T41 ∴ σ T41 A1 = I1A1 σ T42 A2 = I1A2 T2 4 I2 = T1 I1 T2 I2 1/4 = = 104 1/4 = 10 T1 I1 T2 = T1 ×10 60000K° (a) 𝛽 D. λ 1 × 5 × 10−7 = = = 1.25 mm 2 2. d 2 × 2 × 10−4 (a) Q VC2 100 × 20 × 10−6 V1 = = = C1 C1 + C2 30 × 10−6 = 66.67V V2 = V – V1 = 100 – 66.67 = 33.33 (d) R AB = 2 × 10 = 20Ω 3 3 1 i= = = 10 + 20 30 10 1 V = i R AB = × 20 = 2 V 10 V 2 = = = 0.2 v/m L 10 (a) For circular the required centripetal force is provided by magnetic force. m v2 mv I. e. Q v b ∴b= R qr B ≈ 1.6 × 10−8 t (d) ∅ Nab 100 × 10−4 × 5 Current sensitivity = = = i c 10−8 =5 rad/ µamp Page|6 36 (a) G=25 Ω , s=2.5 Ω 𝐼𝐺 𝑆 = 𝐼𝑜 𝑆 + 𝐺 2.5 = 2.5 + 25 2.5 = 27.5 25 = 275 1 = 11 37 (d) ev M = IA = 2πr 𝐴 = e. f. A. = e. f. π r 2 = VR = 220 V = 220 Volt ∴ I = 44 (d) 2 = 1 VR2 + VL − VC K. E.1 1 = k. E.2 2 45 (c) Longest wavelength for B Series = 36 5R 𝐿𝑜𝑛𝑔𝑒𝑠𝑡 𝑤𝑎𝑣𝑒𝑙𝑒𝑛𝑔𝑡 𝑓𝑜𝑟 𝐿. 𝑠𝑒𝑟𝑖𝑒𝑠 = =1.6 × 10−19 × 6.8 × 1015 × 3.14 × 0.53 × 10−10 2 = 9.596 × 10−24 ≈ 9.6 × 10−24 Am2 39 (a) a when R is negligible, 1 1 n= = 2π LC 2π 10−2 × 25 × 10−6 104 103 = = 10𝜋 𝜋 π T= 3 milli second 10 sec = π T 3T 5T as energy is magnetic at time t = , , 2 2 2 Therefore, t = 1.57,4.74,7.85 … … milli second 41 (c) VL = VC from given relation V = EV 220 = = 2.2A R 100 4 3𝑅 𝜆𝐵 36 3𝑅 27 1 = × = ,𝜆 ∝ 𝜆𝐿 5𝑅 4 5 𝑣 𝜆𝐵 5 𝜆𝐿 27 = 𝑜𝑟 = 𝜆𝐿 27 𝜆𝐵 5 48 (c) V 5 One diode is reverse bias I=R = 10 = 0.5 A 2 Page|7