Question

SCIENUD
NAVNEET
. Answer the following questions as
12. What is meant by Valency?
13. In an electric circuit. how can the battery having 12 V be shown symbolically?
14. "I am a chief constituent of blogas. Identify me Methane
15. Mention the full form of CFC chlorofluoro Carbon
16. Which tree leaves are used in manufacture of bidies? Tendu
Section B
Answer the following 9. no. 17 to 26 (within the limit of 40 to 50 words) as
20
directed : [2 marks each)
17. A milkman adds a very small amount of baking soda to fresh milk.
(A) Why does he make the milk slightly alkaline ?
(B) Why does the milk take a long time to set as curd ?
18. Give scientific reason : Hydrogen gas is not evolved when copper reacts with dilute H2SO4
19. An atom has electronic configuration 2, 8, 7.
(A) What is the atomic number of this element ?
(B) To which of the following elements would it be chemically similar ? (Atomic
numbers are given in parentheses.)
N(7). F(9), P(15), Ar(18)
OR
Answer the following questions based on depiction of Group 17 of Group 17
modern periodic table :
(A) State whether A is a metal or non-metal.
(B) State whether A is more reactive or less reactive than C.
20. State the name of any four organs of human digestive system.
OR
State the name of any four organs of human respiratory system.
21. If any animal is cut into many pieces, can a new complete animal body be generated
from each piece? If yes, then explain such event.
22. Draw the ray diagrams showing incident ray and reflected ray for (1) a ray parallel
to the principal axis and (2) a ray passing through the principal focus of a concave
mirror.
B. State the advantages / merits of a series combination of resistors.
OR
State two practical applications of heating effect of electric current
24. Explain : An electric fuse is an important component of all domestic circuits.
25. Distinguish between biodegradable waste and non-biodegradable waste.
26. Explain : (1) Refuse and (2) Repurpose aspects to save environment.
OR
Which four steps would you suggest to reduce the use of energy?​

Answer 1

Answer:

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