Question

Choose the correct option from following 1×4=4

1)While cooking,if the bottom of the vessel is getting blackened on the Outside,it means that

A.the food is not cooked completely

B.the fuel is not burning completely

C.the fuel is wet

D.the fuel is burning completely

2)Aquatic animals breathe faster in water because

a. they breathe dissolved carbon dioxide

b. they have to breathe dissolved oxygen

c. oxygen level is high in water

d. oxygen level is very low in water

3)Hydrogen gas is not evolved when a metal reacts with concentrated nitric acid because

a. nitric acid is a strong oxidizing agent

b. nitric acid is a strong reducing agent

c. nitric acid is a weak oxidizing agent

d. nitric acid is a weak reducing agent

4)Which part of the solar cooker is responsible for greenhouse effect?

a. Coating with black colour inside the box

b. Mirror

c. Glass sheet

d. Outer cover of the solar cooker

Answer the following in one or two sentences 1×4= 4

5). State Snells law.

6)Write any two reason why Mendel choose pea plant for his experiment.

7)Write any one function of pituitary gland.

8)Why is 18 group elements called noble gases?

Answer the following questions 2×5=10

9)Define Ohms law

10)Write the preventive measures of corrosion

11) When an object is placed (a) at c and (b) at f in the concave mirror what is position

nature and size of the image

12)What is rainwater harvesting?

13)Define Food chain and Food Web

Answer the following questions 3×5=15

14)a. Why forests are called biodiversity hotspots

b. Mention any four stakeholders for conservation of forest and wildlife.
16) draw neat labelled diagram of bio gas plant

17)Write the functions of a) Gibberellins b)Cytokinin c)Abscisic acid

18) draw diagram to show reaction of zinc granules with dilute sulphuric acid and testing

hydrogen gas by burning.

Answer the following questions 4×3=12

19)A student fixes a sheet of paper on a drawing board.He places a bar Magnet in the center

of it.He sprinkles some iron fillings uniformly Around the barmagnet.Then he taps the board

gently and observes That their on fillings arrange themselves in a particular pattern

a)Why do the iron fillings arrange in a pattern?

b)What does the lines along which the iron fillings align represent?

c)How does the strength of magnetic fieldlines is indicates?

20)In human females,what happens when

i)egg is fertilized

ii)egg is not fertilized

21)(a) Define 1 watt.

(b) State the commercial unit of electric energy. Express it in terms of SI unit of energy.

(c) An electric refrigerator rated as 750 W operates 8 hours per day. What is the cost of the

energy to operate it for a month of June at Rs. 2.50 per kWh?

Answer the following 1×5=5

22)Atoms of eight elements A. B. C. D, E, F. G and H have the same number of shells but

different number of electrons in their outermost shell. It was found that elements A and G

combine to form an ionic compound. This compound is added in a small amount to almost all

vegetable dishes during cooking. Oxides of elements A and B are basic in nature while those

of E and F are acidic. The oxide of D is almost neural. Based on the above information

answer the following questions:

i) To which period of the periodic table do the listed elements belong?

ii) What would be the nature of compound formed by a combination of elements B and F?

iii) Which two of these elements could definitely be metals?

iv) Which one of the eight elements is to be found in gaseous state at room temperature?

v) If the number of electrons in the outermost shell of elements C and G are 3 and 7

respectively, write the formula of the compound formed by the combination of C and G​

Answer 1

Answer:

1)B

2)B

3)A

4)C

5) Snell's law states that the ratio of the sine of angle of incidence in the first medium to the sine of angle of refraction in the second medium is a constant for a given pair of media and for a given wavelength of light .

6) for his experiments, Mendel selected pea ( pisum sativum) plant because numerous varities of peas with many different traits ( hereditary characteristics) were available . pea was easy to cultivate, easy to breed and produced new generaz within a reasonable short time.

7) To secrete harmones into your bloodstream.

8)The noble gases are in group 18 (8A). they are helium,neon,argon, krypton,xenon,and radon. they were once called inert gases because they were thought to be vompi inert-- unable to form compounds .... becoz this configuration is extremely stables as well as symmetrical , the noble gases are very unreactive.

9) A law stating that electric current is proportional to voltage and inversely proportional to resistance.

10) methods of stopping & preventing metal corrosion

1. turn to non- corrosive metals such as aluminum and stainless steel.
2. keep the area around the metal surface dry .
3. use drying agents and moisture barrier products.

4.make sure underground piping is laid in a layer of backfill ,such as limestone .

12)Rain water harvesting is the process of collecting the rain water which used to run off from te roof tops, parks, roads, and tanks.

...... also it is recharged to the ground water to reuse the water . instead of letting the rainwater to run off and go waste ,it is stored and used for future purpose