CBSE Class 10 Marking Scheme 2022 for Science

Sample Question Paper (TERM – I) 2021-22
Class X
Science (086)

Q.NO ANSWERS

Section - A

1. B. Yellow precipitate is formed

2. B. Hydrogen

3. D. ii and iv

4. B. 3Fe(s) + 4H2O(g) → Fe3O4 (s) + 4H2(g)

5. D. D

6. A. Fe and Fe respectively.

7. C. Combination reaction

8. B H2CO3 Ca(OH) 2

9. A. By adding acid to water with constant stirring.

10. C. To verify the Law of conservation of mass

11. C. (iii) Alveoli: Thin-walled sac like structures for exchange of gases.

12. B. (i) - amylase, (ii) - pepsin, (iii) - trypsin

13. D. water content in the guard cells

14. D. (iv) Vena cava takes blood from body parts to right auricle

15. B. Blood is transferred to lungs for oxygenation and is pumped into various organs
simultaneously.

16. B. i.- b) ; ii – c) ; iii – d) ; iv- a)

17. C. Concave mirror

18. C.

19. A. Concave mirror as well as convex lens

20. C. The speed of light in air > the speed of light in water > the speed of light in glass.

21. D. r < v

22. B. The mirror has a focal length of -3 cm and will produce an image of magnification
-1.

23. B. 0°

24. B. (ii)

Section - B

25. C.  

26. A. 2002

27. B. Mg reacts with dil. HCl to produce H2 gas which helps in floating

28. B. B, C

29. B. ii and iii

30. B. i and iv

31. C. A is true but R is false

32. D. A is False but R is true

33. C. A is true but R is false.

34. B. Both A and R are true and R is not the correct explanation of A.

35. B. B and D

36. D. Shark, dog fish, sting ray

37. D. Thin walled capillaries richly supplied with blood.

38. B. They selectively filter toxic substances through their leaves.

39. C. concave lens of focal length -25 cm
P = -4 D
100
P =
𝑓(𝑐𝑚 )
100
f(cm) = 𝑝
100
−4
= -25 cm.
Negative focal length means concave lens. Concave lens of focal length -25cm.

40. A. 30 cm in front of the mirror
If rays converge at a point 15cm from the mirror, then,
f = -15cm
then, C = -30cm
An object kept at C makes an image of the same size as object correct answer –
(A) 30cm in front of mirror

41. B. yeast, mushroom, bread mould

42. D. Urine is more diluted.

43. D. -80/3 cm
m = -3
V = 80cm
𝑣
m=
𝑢
80
-3 =
𝑢
80 −80
u = −3 = 3 cm.
−80
Correct answer = (D) cm.
3

44. C. ii, iii and iv

45. D. Medium 1 and 3 are essentially the same medium, but medium 2 is denser than
1 and 3

46. B. 1.21
𝑅.𝐼 𝑜𝑓 𝑓𝑙𝑖𝑛𝑡 𝑔𝑙𝑎𝑠𝑠
Refractive index of flint glass w.r.t alcohol =
𝑅.𝐼 𝑜𝑓 𝑎𝑙𝑐𝑜 𝑕𝑜𝑙
1.65
= 1.36 = 1.21
Correct answer –(B)1.21

47. C. 4 mm
f = +10cm (Convex lens)
𝑕1 = 2mm = 0.2cm.
u = -5cm.
1 1 1
𝑓
= 𝑣−5
1 1 1
= −
𝑣 10 5
1−2 −1
10
= 10
V = -10cm.
𝑣 𝑕
m= 𝑢 = 𝑕 2
1
−10 𝑕
m= −5 = 0.22
 𝑕2 = 0.4cm.

𝑕2 = 4mm

Correct answer (C) 4mm

48. B. X, Y, Z

Section - C

49. C. CaCO3

50. C. 18 g

51. A. Brine

52. A. Between 1 to 3

53. C. Carbon dioxide

54. B. Carbon dioxide

55. B. Blue - black colour would be obtained on the leaf of plant Y and no change in
colour on leaf of plant X.

56. C. i. and iii

57. B. a parallel-sided glass block

58. C. 300
sin 𝑖
Refractive index of medium =
sin 𝑟
sin 48.6°
1.5 = sin 𝑟
0.75
1.5 =
sin 𝑟
0.75
sin 𝑟 = 0.5
sin 𝑟 =0.5
r= sin−1 (0.5)
r= 30°
Correct answer (C) 30°

59. D. III and V are correct.

60. A. lateral shift of the rays would have been less.

***

Marking Scheme in lieu of diagram based questions for VI candidates
Section - A
2. B. Hydrogen
3. D. Zinc
5. B. Acidic
11 A. Alveoli: Thin-walled sac like structures for exchange of gases.
12
L M N
B amylase pepsin trypsin
14 D. Vena cava - takes deoxygenated blood from body parts to right atrium
15. B. Blood is transferred to lungs for oxygenation and is pumped into
various organs simultaneously.
16. B. i.- b) ; ii – c) ; iii – d) ; iv- a)
18. C. It is a convex lens and the object is placed between pole and focus.
22. B. The mirror will produce an image of magnification -1.
23. B. 0°
24. B. Violet.
Section - B
26. B. Rain water consists of dissolved oxides of sulphur.
27. B. Mg reacts with dil. HCL to produce H2 gas which helps in floating.
30. B. I and iv
44. C. pass through the centre of curvature.
45. D. glass is optically denser than water.
47. C. 4 mm
Section - C
53. C. Carbon dioxide
54. B. Carbon dioxide
55. B. Blue - black colour would be obtained on the leaf of plant B
56. C. i. and iii
57. A. Dispersion
58. B. Red colour is monochromatic.
59. D. Different wavelengths travel at different speeds in the glass.
60. C. Rainbow.

***