Q. Write a and b in the given flow chart of neuron through which information travels as an electrical impulse.

Dendrite $\to$ a $\to$ b $\to$ End point of neuron

Q. Two lamps, one rates $100$W; $220$V, and the other $60$W; $220$V are connected in parallel to electric mains supply. Find the current drawn by two bulbs from the line, if the supply voltage is $220$V.

Q. Write Joule's law of heating.

Q. Name one gustatory receptor and one olfactory receptor present in human beings.

Q. List the factors on which the resistance of a conductor in the shape of a wire depends.

Q. As an individual, what can we do to generate the least garbage? Give two points.

Q. The pH of a salt used to make food items, like cakes, is $9$.

Q. Name the scientist who first of all showed that atomic number of an element is a more fundamental property than its atomic mass.

Q. Decomposition reactions require energy either in the form of heat or light or electricity for breaking down the reactants. Write one equation each for decomposition reactions where energy is supplied in the form of heat, light and electricity.

Q. How is copper extracted from its sulphide ore? Explain the various steps supported by chemical equations.
Draw labelled diagram for the electrolytic refining of copper :

Q. If the image formed by a spherical mirror for all positions of the object placed in front of it is always erect and diminished, what type of mirror is it? Draw a labelled ray diagram to support your answer.

Q. $2$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 metal reacts with dilute solution of a strong acid.

Q. Why are alloys commonly used in electrical heating devices? Give reason.

Q. A compound $X$ on heating with excess conc. sulphuric acid at $443K$ given a saturated compound $Y$. $X$ also reacts with sodium metal to evolve a colourless gas $Z$. Identify $X,Y$ and $Z$. Write the equation of the chemical reaction of formation of $Y$ and also write the role of sulphuric acid in the reaction.

Q.

Name the hormones secreted by the following endocrine glands and specify one function:

1. Thyroid

2. Pituitary

Q. Why are most carbon compounds poor conductors of electricity?

Q. Write one main difference between asexual and sexual mode of reproduction. Which species is likely to have comparatively better chances of survival- the one reproducing asexually or the one reproducing sexually? Give the reason to justify your answer.

Q. What is meant by power of a lens? Write its SI unit. A student uses a lens of focal length $40$ cm and another of $-20$ cm. Write the nature and power of the lens.

Q. Suggest two measures to manage the garbage we produce.

Q. What is the dam? Why do we seek to build large dams? While building large dams, which three main problems should particularly be addressed to maintain peace among local people? Mention them.

Q. After the emission of one $\alpha$-particle followed by two $\beta$- particles from ${}_{92}^{238}U$the number of neutrons in the newly formed nucleus is

1. $142$
2. $146$
3. $140$
4. $144$

Q. Write the energy conversion that takes place in a hydropower plant.

Q. State the laws of refraction of light. Explain the term 'absolute refractive index of a medium' and write an expression to relate it with the speed of light in vacuum.

Q. Why are metals good conductors of electricity whereas glass is a bad conductor of electricity? Give reason.

Q. Show how would you join three resistors, each of resistance $9$ $\Omega$ so that the equivalent resistance of the combination is $13.5\Omega$?

Q. Write the name and structure of a saturated compound in which $4$ carbon atoms are arranged in a ring. Give the number of single bonds present in this compound.

Q. Write the steps involved in the extraction of pure metals in the middle of the activity series from their carbonate ores.

Q. State Modern periodic law.

Q. A Mendelian experiment consisted of breeding pea plants bearing violet flowers with pea plants bearing white flowers. What will be the result in $F_1$ progeny?

Q. List two values the teacher instilled in his students in this episodes.