SECTION
A
(A). Short- Answer question: 1X20=20
1.
State the cause of refraction of light?
2.
What is the minimum number of rays required for locating an image
formed by a concave lens for an object?
3.
A magnesium ribbon is burnt in oxygen to give a white compound ‘X’
accompanied by emission of light. Write a
balanced chemical equation,
when ‘X’ is dissolved in water.
4.
Indicate the oxidising and reducing agent in the reaction.
H2S + Cl2
------- 2HCl + S
5.
Two green plants are kept separately in oxygen free containers, one in the
dark and the other in continuous light.
Which one will live longer? Give
reasons.
6.
Mention any one point of difference between Pepsin and Trypsin.
7.
A doctor has prescribed a corrective lens of power +1.5 D. Find the focal
length of the lens. Is the prescribed lens
diverging or converging?
8.
State the Laws of Reflection.
9.
Give reason why acids are not stored in metal containers?
10.
Write a balanced chemical equation for a neutralisation reaction,
mentioning the physical state of the
reactants and products.
11.
What will happen if platelets were absent in the blood?
12.
Define excretion.
13.
Why is a normal eye not able to see clearly the objects placed closer
than 25 cm?
14.
Which phenomenon is responsible for making the path of light visible?
Or
Study the diagram and answer the question
that follows:
Identify the defect of vision represented
by this diagram.
15.
What is reflex action?
16.
What is tropic movement?
Assertion
and Reason
Direction- Q. No. 17 to 20 –
a. Both
Assertion (A) and Reason (R) are true and Reason(R) is the correct explanation
of Assertion (A).
b. Both
Assertion (A) and Reason (R) are true but Reason(R) is not a correct
explanation of Assertion (A).
c. Assertion
(A) is true but Reason (R) is false.
d. Assertion
(A) is false but Reason (R) is true.
17.
Assertion (A): The following
chemical equation,
2C6H6 + 7/2O2-------
4CO2 + 3H2O
Is a balanced chemical equation.
Reason (R): In a balanced chemical equation, the
total number of atoms
of each element are equal on both sides of
the equation.
18.
Assertion (A): White silver chloride
turns grey in sunlight.
Reason
(R): Decomposition of silver chloride in presence of sunlight
takes place to form silver metal and
chlorine gas.
19.
Assertion (A): Higher is the
refractive index of a medium or denser the
medium, lesser is the velocity of light
in that medium.
Reason (R): Refractive index is inversely proportional
to velocity.
20.
Assertion (A): The planets twinkle
while the stars do not.
Reason (R): The planets are much closer to the earth
than the stars.
SECTION
B
(B). Short answer type question: 3X10=30
19.
(a).List the parts of the human eye that control the amount of light entering into it. Explain how they perform
this function.
(b).
Write the function of retina in human eye.
(c).
What do we have to keep in mind when eyes have to donated?
20.
(a).With the help of labelled ray diagram, show the path followed by a
narrow beam of monochromatic light when
it passes through a glass
prism.
(b).
What would happen if this beam is replaced by a narrow beam of white
light?
21.
Write the balanced chemical equations for the following reactions and identify
the type of reaction in each case.
(a).
Nitrogen gas is treated with hydrogen gas in the presence of a catalyst at 773K
to form ammonia gas.
(b).
Ethene is burnt in the presence of oxygen to form carbon dioxide, water and
release heat and light.
22. Define Rancidity and corrosion with suitable
examples.
23.
Write two different ways in which glucose is oxidized to provide energy in
human body. Write the products formed in each case.
24.
Why is transpiration important for plants?
25.
Name the hormones secreted by the following endocrine glands and specify one
function of each:
(a).
Thyroid
(b).
Pituitary
(c).
Pancreas
26.
The magnification of an image formed by a lens is -1. If the distance of the
image from the optical centre of the lens is 25 cm, where is the object placed?
Find the nature and focal length of the lens. If the object is displaced 15 cm
towards the optical centre of the lens, where would the image be formed? Draw a
ray diagram to justify your answer.
Or
Rohit
focused the image of a candle flame on a white screen using a convex lens. He
noted down the position of the candle, screen and lens as under:
Position
of candle= 26.0 cm
Position
of convex lens= 50.0 cm
Position
of screen= 74.0 cm
(a).
What is the focal length of the convex lens?
(b).
Where will the image be formed if he shifts the candle towards the lens at a
position of 38cm?
(c).
Draw a ray diagram to show the formation of the image in case (b) as said
above.
27.
Explain the following giving chemical equation in each case:
(a).
Baking soda
(b).
Gypsum is heated at 373K
28.
2 ml of sodium hydroxide solution is added to a few pieces of granulated zinc
metal taken in a test tube. When the contents are warmed, a gas evolves which
is bubbled through a soap solution before testing. Write the equation of the
chemical reaction involved and the test to detect the gas. Name the gas which
will be evolved when the same metals reacts with dilute solution of a strong
acid.
SECTION
C
(C). Long answer type question: 5X6=30
29.
(a). Blood circulation in fishes is different from the blood circulation in
human beings. “justify the statement”.
(b).
Describe the “blood circulation” in Human beings.
30.
(a). Identify the endocrine glands A, B, C, D, E and F in the given diagram.
(b).
List the function of each part.
31.
Equal length of magnesium ribbon are taken in two test tubes ‘A’ and ‘B’. H2SO4
is added to test tube ‘A’ and H2CO3 to the test tube ‘B’
in equal amounts:
(a).
Identify the test tube showing vigorous reaction.
(b).
Give reason to support your answer.
(c).
Name the gas liberated in both the tubes. How will you prove its liberation?
(d).
Write chemical equations for both reactions.
(e).
Out of the two acids taken above:
1. Which one will have lower PH
value?
2.
Which one will have lower H+ concentration?
32.
An object is placed at a distance of 30 cm from a concave lens of focal length
30 cm.
(1)
Use lens formula to determine the distance of the image from the lens.
(2)
List four characteristics of the image (nature, position, size, erect/inverted) in this case.
(3)
Draw a labelled diagram to justify your answer of part (2).
33.(a).
What is meant by scattering of light? Mention the factor on which it depends.
(b).
An astronaut in space finds sky to be dark. Explain reason for this
observation.
34.
(1). Balance the following chemical equations:
(a)
NaOH + H2SO4 ------- Na2SO4 + H2O
(b)
PbO + C --------- Pb + CO2
(c)
Fe2O3 + Al ------ Al2O3 + Fe + Heat
(2).
Write the balanced chemical equations for the following reactions:
(a).
Barium chloride + Potassium sulphate --------Barium sulphate +
Potassium chloride
(b).
Zinc + Silver nitrate --------- Zinc nitrate + Silver
Comments
Post a Comment