Q. Name and define the SI unit of current

Q. Write the name of the main constituent of biogas. Also state its percentage.

Q. Write the name, symbol and electronic configuration of an element X whose atomic number is 11.

Q. Can the following groups of elements be classified as Dobereiner's triad:

Q. Write the structure of eye lens and state the role of ciliary muscle in the human eye.

Q. Identify the acid and base which form sodium hydrogen carbonate . Write chemical equation in support of your answer. State whether its compound is acidic, basic or neutral. Also write its pH value.

Q. $2$g of silver chloride is taken in a china dish and the china dish is placed in a sunlight for sometime. What will be your observation in this case? Write the chemical reaction involved in the form of a balanced chemical equation. Identify the type of chemical reaction.

Q. Identify the type of reactions taking place in each of the following cases and write the balanced chemical equation for the reactions:

Q. Define the term transpiration . Design an experiment to demonstrate this process.

Q. What is feedback mechanism of hormonic regulation. Take the example of insulin to explain this phenomenon.

Q. What are plants hormones ? Name the plant hormones responsible for the following:
(i)Growth of stem
(ii)Promotion cell division
(iii)Inhibition of growth
(iv)Elongation of cells

Q. Name the plant Mendel used for his experiment. What type of progeny was obtained by Mendel in $F_1$ and $F_2$ generations when he crossed the tall short -plants? Write the ratio he obtained in $F_2$ generation plants.

Q. List two differences between acquired traits and inherited traits by giving an example of each.

Q. Why should there be equitable distribution of resources ? List three forces that would be working against an equitable distribution of our resources.

Q. How can we help in reducing the problem of waste disposal? Suggest any three methods.

Q. Define an ecosystem. Draw a block diagram to show the flow of energy in an ecosystem.

Q. What is a rainbow? Draw a labelled diagram to show the formation of a rainbow.

Q. Write the chemical formula and name of the compound which is the active ingredient of all alcoholic drinks. List its two uses. Write chemical equation and name of the product formed when this compound reacts with-
(i) Sodium metal
(ii) Hot concentrated sulphuric acid

Q. What is methane? Draw its electron dot structure. Name the type of bonds formed in this compound. Why are such compounds
(i) Are Poor conductors of electricity and
(ii) Have low melting and boiling points? What happens when this compound burns in oxygen?

Q. Write chemical equation for the following reaction:

Q. What are alloys? List two properties of alloys.

Q. An object is placed at a distance of $30$ cm from a concave lens of focal length $30$ cm.
(i) Use lens formula to determine the distance of the image from the lens.
(ii) List four characteristics of the image (nature position, size, erect/inverted) in this case.
(iii) Draw a labelled diagram to justify your answer apart (ii)

Q. (a) With the help of a suitable circuit diagram prove that the reciprocal of the equivalent resistance of a group of resistance joined in parallel is equal to the sum of the reciprocal of the individual resistances.
(b) In an electric circuit two resistors of $12\Omega$ each are joined in parallel to a $6V$ battery. Find the voltage drawn from the battery.

Q. What is a solenoid? Draw the pattern of magnetic field lines of
(i) A current carrying solenoid and
(ii)A bar magnet. List two distinguishing features between the two fields.

Q. Define pollination. Explain the different types of pollination. List two agents of pollination? How does suitable pollination lead to fertilization?

Q. (a) Identify the given diagram. Name the parts 1 to 5.
(b) What is contraception ? List three advantages of adopting contraceptive measures.

Q. An electric lamp of resistance $20\Omega$ and a conductor of resistance $4\Omega$ are connected to a $6V$ battery as shown in the circuit. Calculate:
(a) The total resistance of the circuit
(b) The current through the circuit
(c)The potential difference across the (i) Electric lamp and (ii) Conductor, and
(d) Power of the lamp.

Q. A student ids observing a temporary mount of a leaf peel under a microscope. Draw labelled diagram of the structure of stomata as seen under the microscope.

Q. List four precautions which a student should observe while determining the focal length of a given convex lens by obtaining the image of a distant object on a screen.

Q. While studying the dependence of potential difference (V) across a resistor on the current (I) Passing through it, in order to determine the resistance of the resistor, a student took $5$ readings for different values of current and plotted a graph between V and I. He got a straight line graph passing through the origin. What does the straight line signify? Write the method of determining resistance of the resistor using this graph.