(a) Write the molecular formula of the following carbon compounds: (i) Methane (ii) Propane. (b) Carbon compounds have low melting and boiling points. Why?
Science 2022 board paper
24 questions · 51 marks counted · grouped by chapter, each linked to the topic it tests.
Carbon and its Compounds
3 questions · 8 marks
(i) Write the molecular formula of benzene and draw its structure. (ii) Write the number of single and double covalent bonds present in a molecule of benzene. (iii) Which compounds are called alkynes?
Draw two different possible structures of a saturated hydrocarbon having four carbon atoms in its molecule. What are these two structures of the hydrocarbon having same molecular formula called? Write the molecular formula and the common name of this compound. Also write the molecular formula of its alkyne.
How do Organisms Reproduce?
3 questions · 7 marks
Which one of the two multicellular organisms - Spirogyra and Planaria reproduces by regeneration and why? Give an example of any other organism which can also reproduce by the same process.
(a) Which of the following flowers will have higher possibility of self-pollination? Mustard, Papaya, Watermelon, Hibiscus. (b) List the two reproductive parts of a bisexual flower.
(a) Mention one function each of the following organs in human male reproductive system: (i) Testis (ii) Scrotum (iii) Vas deferens (iv) Prostate gland. (b) Name the type of germ cell which (i) is motile, and (ii) stores food.
Heredity
6 questions · 10 marks
(i) In a cross between violet flowered plants and white flowered plants, state the characteristics of the plants obtained in the F_1 progeny. (ii) If the plants of F_1 progeny are self-pollinated, then what would be observed in the plants of F_2 progeny? (iii) If 100 plants are produced in F_2 progeny, then how many plants will show the recessive trait?
What is variation? List two main reasons that may lead to variation in a population.
Sex-determination in humans: humans have 46 (23 pairs) chromosomes; 44 (22 pairs) control body characters and 2 (one pair) are sex chromosomes of two types - X chromosome and Y chromosome; at fertilisation the type of male gamete that fuses with the female gamete decides the sex of the newborn. Why is a pair of sex chromosomes in human beings called a mismatched pair in terms of type and size?
Sex-determination in humans (46 chromosomes: 44 autosomes + 2 sex chromosomes X and Y; sex of newborn decided by which male gamete fuses with the female gamete). Out of male or female, which of them has a perfect pair of sex chromosomes? In case of a perfect pair, will the gametes produced be of the same kind or of a different kind?
Sex-determination in humans (46 chromosomes: 44 autosomes + 2 sex chromosomes X and Y; sex of newborn decided by which male gamete fuses with the female gamete). Write the names of two organisms whose sex determination is not done on a genetic basis. Explain the process of their sex determination.
Sex-determination in humans (46 chromosomes: 44 autosomes + 2 sex chromosomes X and Y; sex of newborn decided by which male gamete fuses with the female gamete). With the help of a flow chart only, show how sex determination in human beings takes place genetically.
Electricity
3 questions · 9 marks
(a) Three resistors R_1, R_2 and R_3 are connected in parallel and the combination is connected to a battery, an ammeter, a voltmeter and a key. Draw suitable circuit diagram to show the arrangement of these circuit components along with the direction of current flowing. (b) Calculate the equivalent resistance of the following network: [network shown: along line A-C-D-B, R_1 = 5 ohm is between A and C and R_4 = 5 ohm is between D and B; between C and D, R_2 = 10 ohm (upper branch) and R_3 = 10 ohm (lower branch) are in parallel].
(i) Define Electric Power and write its SI unit. (ii) Two bulbs rated 100 W; 220 V and 60 W; 220 V are connected in parallel to an electric mains of 220 V. Find the current drawn by the bulbs from the mains.
(i) State Joule's law of heating. Express it mathematically when an appliance of resistance R is connected to a source of voltage V and the current I flows through the appliance for a time t. (ii) A 5 ohm resistor is connected across a battery of 6 volts. Calculate the energy that dissipates as heat in 10 s.
Magnetic Effects of Electric Current
6 questions · 10 marks
A girl student fixes a white paper sheet on a drawing board using a sticky material. She places a bar magnet at its centre and, using a salt-sprinkler, uniformly sprinkles some iron filings around the bar magnet. On tapping the board gently she observes that the iron filings have arranged themselves in a particular pattern. Draw a diagram to represent this pattern of iron filings.
Iron filings sprinkled around a bar magnet on a tapped drawing board arrange into a pattern. Draw the magnetic field lines of a bar magnet. Show on it the poles of the bar magnet and the direction of the magnetic field lines.
Iron filings sprinkled around a bar magnet on a tapped drawing board arrange into a pattern. How is the direction of the magnetic field at a point determined using field lines? Why do two magnetic field lines not intersect each other?
Iron filings sprinkled around a bar magnet on a tapped drawing board arrange into a pattern. How are the magnetic field lines of a bar magnet drawn using a small compass? Draw one magnetic field line on each side of the magnet.
(i) What is a solenoid? (ii) Draw the pattern of magnetic field lines of the magnetic field produced by a solenoid through which a steady current flows.
(i) Name and state the rule to determine the direction of force experienced by a current carrying straight conductor placed in a uniform magnetic field which is perpendicular to it. (ii) An alpha particle while passing through a magnetic field gets projected towards north. In which direction will an electron project when it passes through the same magnetic field?
Our Environment
3 questions · 7 marks
(i) List two human-made ecosystems. (ii) "We do not clean a pond in the same manner as we do in an aquarium." Give reason to justify this statement.
(a) Name the group of organisms which form the first trophic level of all food chains. Why are they called so? (b) Why are human beings most adversely affected by bio-magnification? (c) State one ill-effect of the absence of decomposers from a natural ecosystem.
What is ozone? How is it formed in the upper layers of the Earth's atmosphere? How does ozone affect our ecosystem?