Q. Hydrogen being a highly inflammable gas and oxygen being a supporter of
combustion, yet water which is a compound made up of hydrogen and oxygen is
used to extinguish fire. Why?
Q. What happens chemically when quicklime is added to water filled in a bucket?
Q. What change in colour is observed when white silver chloride is left exposed to
sunlight? State the type of chemical reaction in this change.
Q. The pH of a sample of vegetable soup was found to be 6.5. How is this soup likely
to taste?
Q. Write a balanced chemical equation for the reaction between sodium carbonate
and hydrochloric acid indicating the physical state of the reactants and the products.
.Q Name the gas usually liberated when a dilute acid reacts with a metal. What
happens when a burning candle is brought near this gas?
Q. Name the natural source of each of the following acid
(i) Citric acid. (ii)Oxalic acid.
(iii)Lactic acid. (iv)Tartaric acid
Q. Why does calcium float in water?
Q. Explain how antacid works.
Q. A student detected the pH of four unknown solution A, B, C and D as follows 11, 5,
7 and 2. Predict the nature of the solution.
Q. State the chemical name of Plaster of Paris. Write a chemical equation to show the
reaction between Plaster of Paris and water.
Question. Give the names of the following functional groups:
(i) —OH (ii) —COOH
Question. Name the carbon compound which on heating with excess of concentrated
sulphuric acid at 443 K gives ethene.
Question. Draw the structure of CH3COOH molecule.
Q. What would be the consequences of deficiency of hemoglobin in your body?
Q. Give one reason why multicellular organisms require special organs for exchange of
gases between their body and their environment. :
Q. What is‘translocation’in plants?
Q. Smita’s father has been advised by a doctor to reduce his sugar intake.
1. Name the disease he is suffering from and name the hormone whose deficiency is? ,
2. Identify the gland that secretes it and mention the function of this hormone.
3. Explain how the time and amount of secretion of this hormone is regulated in human
system.
Q. State the functions of plant hormones. Name four different types of plant hormones.
Question. Name the largest cell present in the
human body.
Question. “Variations that confer an advantage to
an individual organism only will survive in a population.” Justify.
Question. List any four reasons for vegetative propagation being practised in the growth
of some type of plants.
Q. What is a sex chromosome?
Q. How is the equal genetic contribution of male and female parents ensured in the progeny?
Q. “The refractive index of diamond is 2.42”. What is the meaning of this statement in relation to
speed of light?
Q...Which kind of mirrors are used in the headlights of a motor-car and why
Q. Redraw the diagram given below in your answer book and show the direction of the light ray after
reflection from the mirror.
Q Redraw the diagram given below in your answer book and show the direction of the light ray after
reflection from the mirror
Q. Redraw the diagram given below in your answer book and show the direction of the light ray after
refraction from the lens
Q. Study the diagram given below and answer the questions that follow it:
(a) Which defect of vision is represented in this case? Give reason for your answer.
(b) What could be the two causes of this defect?
(c) With the help of a diagram show how this defect can be corrected by the use of a
suitable lens.
Q. What happens to resistance of a conductor when its area of cross-section is increased?
Q. Two resistors of 10 Ω and 15 Ω are connected in series to a battery of 6 V. How can the
values of current passing through them be compared?
Q. Draw a schematic diagrams of an electric circuit comprising of 3 cells and an electric bulb,
ammeter, plug-key in the ON mode and another with same components but with two bulbs in
parallel and a voltmeter across the combination.
Q.The wattage of a bulb is 24 W when it is connected to a 12 V battery. Calculate its effective
wattage if it operates on a 6 V battery (Neglect the change in resistance due to unequal heating
of the filament in the two cases).
Q. A positively charged particle (alpha-particle) projected towards west is deflected towards
north by a magnetic field. The direction of magnetic field is
(a) towards north (b) towards east
(c) downward (d) upward
Q.What is meant by the term ‘frequency of an alternating current’? What is its value in India?
Why is an alternating current considered to be advantageous over direct current for long range
transmission of electric energy?
Q. A black surface absorbs more heat radiations as compared to a white or a
reflecting surface under identical conditions. List two solar devices which make use of this
property in their design.
Q. What is a solar cell panel? Mention any three of its applications.
Q. What are the various steps in a food chain called?
Q. What is water harvesting? Mention any two water harvesting structures.
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