Assertion: A solution is a homogenous mixture of two or more substances.
Reason :a solution scatters a beam of light passing through it.
SECTION B
2 MARKS QUESTION
18. List any two properties of colloid
19. why is crystallization technique considered better than simple evaporation to purify the
solids
20. Name the technique to separate
a) butter from curd b)camphor from Salt
21. what is the role of epidermis in plants
Section-C
3 MARKS QUESTION
22. list two differences between distance and displacement.
23. A solution of Urea in water contains 16 gram of it in 120 gram of solution find out the mass
percentage of the solution.
24. A) why is plasma membrane called selectively permeable membrane?
B) which organelle is known as powerhouse of the cell.why.
25. Give the names of the elements present in the following compounds
a) quicklime b) hydrogen Bromide c) baking powder d)Potassium Sulphate
SECTION- D
5 MARKS QUESTION
26. Derive the mathematical relation of Newton's second law of motion
or
Derive the mathematical formula of conservation of momentum.
27. From a rifle of mass 4 kg A bullet of mass 50 gram is fired with an initial velocity of 35 metre
per second calculate the initial recoil velocity of the rifle .
Or
Draw well labelled dia of neuron.
Answers
18.
properties of colloid =
It is a heterogeneous mixture having particle size between 1 nm to 100 nm. Size of particles is very small, cannot be seen with naked eyes. It scatters a beam of light. They are stable as the particles do not settle when left undisturbed.
19.
Crystallization is the better method of separating the mixture than evaporation. This is because, on evaporation, some of the solid particles in mixture get decomposed leaving behind impurities whereas, in crystallization, pure crystals of solids are obtained.
20.
(i) Butter from curd can be separated by the technique of centrifugation. (ii) Salt from sea water can be separated by the technique of crystallization or by the evaporation. (iii) Camphor is sublimable but salt is not. So, camphor can be separated from salt sublimation technique.
21.
Epidermis, in botany, outermost, protoderm-derived layer of cells covering the stem, root, leaf, flower, fruit, and seed parts of a plant. The epidermis and its waxy cuticle provide a protective barrier against mechanical injury, water loss, and infection.
22.
Distance is a scalar quantity that refers to "how much ground an object has covered" during its motion. Displacement is a vector quantity that refers to "how far out of place an object is"; it is the object's overall change in position.
23.
Mass of solute = 100 g
Mass of solvent = 400 g
Mass of solution = 400 + 100 = 500 g
Mass % of solution =
Mass of solution
Mass of solute×100
= 500
100×100
=20%
Hence, the correct option is A
24.
A.
The plasma membrane is called a selectively permeable membrane as it permits the movement of only certain molecules in and out of the cells. ... As the plasma membrane acts as a mechanical barrier, the exchange of material from its surroundings through osmosis or diffusion in a cell won't take place.
B.
Mitochondria
Mitochondria are tiny organelles inside cells that are involved in releasing energy from food. This process is known as cellular respiration. It is for this reason that mitochondria are often referred to as the powerhouses of the cell.
25.
(a) Quick lime (b) Hydrogen bromide (c) Baking powder (d) Potassium sulphate. Answer: (a) Quick lime is CaO. Elements present are calcium and oxygen.
26.
1.
Newton's second law of motion states that the acceleration of a system is directly proportional to and in the same direction as the net external force acting on the system, and inversely proportional to its mass. In equation form, Newton's second law of motion is a=F netm a = F net m .
NOTE:
Draw well labelled dia of neuron at the top and 26 question me option thee tu mane 1 kar dea ha...
