#### Creative Important 7 Marks Questions

10th Standard

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Science

Time : 03:00:00 Hrs
Total Marks : 504

Part A

72 x 7 = 504
1. A passenger of mass 72 kg is riding in a lift what is the apparent weight of a person in
(i) descending with constant velocity
(ii) ascending with constant acceleration 3 m/s2?

2. A bullet of mass 50 g moving with a speed of 300 ms-1 is brought to rest in Is. Find the impulse and the force.

3. A body of mass 20 kg is hung by a spring balance in a lift. What would be the weight when (i) The lift is ascending with an acceleration of 2 m/s2
(ii) The lift is descending with a same acceleration of 2 m/s2
(iii) The lift is descending with a constant velocity 2 ms-1
Given g = 10 m/s2

4. A cricket ball of mass 100 g moving with a speed of 20 ms-1 is brought to rest by a player. Find the change in momentum of ball.

5. Two bodies have masses in the ratio 2 : 3 when a force is applied on first body, it moves with an acceleration of 6 ms-2, How much acceleration will be the same force produce in the other body?

6. A body of mass 20 x 10-3 kg when acted upon by a force for 4 second, attains a velocity of 100 m/s. If the same force is applied for 2 minutes, on a body of mass 10 kg at rest, what will be its velocity?

7. A sphere of mass 20 kg moving with a velocity 40 ms-1 collides with another sphere of mass 15kg which is at rest. After collision they move with the same velocity. Find that velocity.

8. A body of mass 2 kg moving with uniform velocity of 40 ms-1 collides with another body at rest. If two bodies move together with a velocity of 20 m-1, Find the mass of the other body.

9. A 2000 kg car traveling at 20 ms-1 hits concrete wall and stops in 0.05 s. What magnitude of impulse did the wall exert on the car?

10. The masses of two planets are in the ratio 1 : 2/ their radii are in the ratio 1 : 2. Find the ratio of the acceleration due to gravity on the planets.

11. If the acceleration due to gravity of a planet is half the acceleration due to gravity of the earth's surface and radius of planet is half the radius of the earth find the mass of planet in terms of mass of earth.

12. When a constant force acts of 10 s on a body of mass 10 kg, which is initially at rest, moves a distance of 500 cm in 10 s. Calculate the frictional force required to bring the body to rest.

13. Force of 50 N acts perpendicular on a body, which is fixed at a point O. The distance of point of action of force from O is 5 cm. Find the moment of force.

14. A person of weight 50 kg is moving down in an elevator Calculate downward acceleration offered by the elevator whose reaction force is 400 N on the surface.

15. Calculate the force of gravitation between two bodies of weight 50 kg and 10 kg respectively place at 10 m apart. If their distance increased to 100 % then find the change in percentage of force. (New force is 75% less than the original force)

16. The diameter of the objective lens is 5 m and wavelength of light is 6000 Å. Find the resolving power of resolution of the telescope.

17. The refractive index of kerosene is 1.44. Find the velocity of light through kerosene.

18. The refractive index of kerosene is 1.44 &that of diamond is 2.42. Calculate the refractive index of diamond with respect to kerosene.

19. Speed of light in glass is 2 x 108 ms-1. Find the refractive index of glass.

20. Alight travels from air into water, the angle of refraction is 25° to the normal. Find the angle of incidence. Refractive index of water is 1.33. μa=1.

21. Light in air enters a diamond at 45°. What is the angle of refraction? G.T μdia = 2.42.

22. A 5 cm tall object is placed fraction to the principle axis of a convex lens of focal length 20 cm. The distance of the object from the lens is 30 cm. Find the (i) Position, (ii) Nature, (iii) Size of the image formed.

23. An object is placed in front of a convex lens of a focal length 10 cm. What is the nature of the image formed if the object distance is 15 cm?

24. An object of height 6 cm is placed at a distance of 20 cm from a concave lens. It's focal length is 10 cm. Find the position and size of the image.

25. A concave lens has focal length of 20 cm. At what distance from the lens a 5 cm tall object be placed so that it forms an image at 15 cm from the lens? Calculate the size of the image formed.

26. A person needs of power -4 D for correcting his distant vision. For correcting his real vision he needs a lens of power +1.5 D. What is focal length of the lens required for correcting..
(i) Distant vision and
(ii) Real vision?

27. The far position of a myopic person is 90 cm in front of the eye. What is the nature and power of the lens required to correct the problem?

28. Draw a diagram to show how hypermetropia is corrected. The real position of hypermetropia eye is 1 m. What is the power of the lens required to correct this defect? G. T real position of the normal is 25 cm.

29. When an object is placed at 25cm from a concave lens, a virtual image is produced at a distance of 10cm. Calculate the magnification produced by the lens.

30. An object placed at 50 cm from a lens produces a virtual image at a distance of 10 cm in front of the lens. What is the focal length of the lens? Is it converging or diverging?

31. A piece of steel has a length 2 m at 200 k. At 250 k its length increases by 0.1 m. Find the coefficient of cubical expansion of steel.

32. If boiling point of water is 95°F, What will be the reading in kelvin scale?

33. An aluminium sheet of length 30 m is made into cone for temperature range ΔT = 300 k. Find the change in length of AI sheet?

34. A metal scale is graduated at 0°C so what would be original length of the object when measured at 25°C, reads 50 Cm? For a metal, the coefficient of linear expansion is 18 x 10-6/ °C.

35. A metal rod 6.522 m long at 285 k expands by 0.576 m at 363 k. Find the coefficient of linear expansion of the metal.

36. At 303 k the volume of an aluminium sphere is 0.3 m3. The coefficient linear expansion αL=24 K-1. If the final volume is 0.35 m3. What is the final temperature of aluminium sphere?

37. 100 W bulb draws 680 mA current. How much time will be required to pass 30 C of charge through the bulb?

38. A current of 6 A flows through metal wire. How many coulombs of charge pass through the wire in 2 miniatures?

39. The amount of work done to move 20C charge from one point to another is 2201. What is the potential difference between these two points?

40. The potential difference between two conductor is 110 V. How much work in moving 5 C charge from one conductor to the other?

41. An electric heater works for 30 min at 120 V and takes energy of 1 - 2 kwh. What is the current drawn by the heater?

42. What is the resistance of heating element of the heater when 20 A current passing through it at a potential of 220 V?

43. A 110 V light bulb takes 0.9 A current and operates 12h / day. Determine the energy consumed by the bulb for 30 days.

44. Find the
(i) equivalent resistance,
(ii) current through each reactor,
(iii) Total current for the given circuit,
(iv) Voltage drop across each resistor.

45. Determine the following quantities of the
given equivalent.
(i) The equivalent resistance
(ii) Total current through the circuit
(iii) The current through each resistor
(iv) Voltage drop across resistor
(v) Power dissipated in each resistor

R= 20Ω; R= 100Ω;R350Ω; V  =125V

46. wire is 1m long, 0.4 mm in diameter &has resistance of 20 fl. Calculate its resistivity.

47. Calculate the energy consumed by 120 w toaster in 20 min.

48. An observer approaches a stationary sound source 1000 Hz at twice the speed of sound. What frequency does the observer hear?

49. What is the frequency heard by a stationary observer when a train approaches with a speed of 30 ms-1. The frequency of the train is 600 Hz and the speed of sound is 340 m/s?

50. A boy hears two different sounds when a race car is moving toward and moving away. If the speed of sound in air is 340 ms-1. The frequency emitted by the car is 800 Hz and the car velocity is 120 ms-1. Find the frequency heard by the boy? (when the car moving forward).

51. Find the speed of sound in air at 9.23° C.

52. At 10° C, how for away is a reflecting surface if you hear an echo in 0.274s?

53. Plutonium - 239 specimen emits radiation of 4.3 x 103 GBq per second convert this disintegrations in terms of curie.
(IBq = 2.703 x 10-11curie)

54. Determine the energy produced in the fission reaction whose mass difference is 3.251 x 10-28 kg.

55. If the following quantity of energy was released during fission, determine the loss in mass that would result.
(a) 8.5 x 1014 J (b) 2.9 x 1017 J

56. Three hundred and fifty atoms of Ur-235 split. If 2.9 x 10-8 J of energy is released from each atom when fission occurs. What nuclear mass was converted into energy?

57. If the loss in mass during a fission reaction is 0.20 g, how much energy will have been produced?

58. How much energy will have been produced if the loss in mass during a fission reaction was 0.025 g?

59. 10Th23491Pa234+ -1e0
Which type of nuclear radiation is being emitted here?

60. In the equation 6C14⟶ 7N14+-1e0 which decay of radioactive carbon-14 results in the new nitrogen - 14 atom.

61. If Gadolinium - 150 undergoes through a - decay what is the new atomic mass of the resulting element?

62. Find the type of decay.
90Th231⟶ 91pa231+_______.

63. Solve this equation for ∝ - decay.
88Ra226 ➝Rn+________

64. Solve this equation for β - decay.
27Co60⇾ Ni+

65. Which unit is a measure of an individual's exposure to gamma radiation?

66. Convert IBq into curie.

67. Complete the following fission reactions:
(a) 92U2350n1 ⇾38Sr90+Xe+30n1
(b) 92U2350n1 ⇾43Tc107+n+50n1

68. Find the gram molecular mass of carbon dioxide (CO2)

69. Calculate the number of moles in 81g of aluminum.

70. Calculate the number of moles in 2g of NaOH.

71. Find the mass of 2.5 mole of oxygen atom.

72. Calculate the number of molecules in 11g of CO2