(a) Define excretion.
(b) Name the basic filtration unit present in the kidney.
(c) Draw excretory system in human beings and label the following organs of excretory system which perform following functions:
(i) form urine
(ii) is a long tube which collects urine from kidney
(iii) store urine until it is passed out
Draw the structural formulae of all the possible isomers of the compound with the molecular formula C3H6O and also give their electron dot structures.
A student observed a permanent slide showing asexual reproduction in yeast. Draw diagrams of the observations he must have made from the slide. Name the process also.
You are given balls and stick model of six carbon atoms and fourteen hydrogen atoms and sufficient number of sticks. In how many ways one can join the models of six carbon atoms and fourteen hydrogen atoms to form different molecules of C6H14.
Name the electric device that converts mechanical energy into electrical energy. Draw the labelled diagram and explain the principle involved in this device.
Draw a circuit diagram of an electric circuit containing a cell, a key, an ammeter, a resistor of 4Ω in series with a combination of two resistors (8Ω each) in parallel and a voltmeter across parallel combination. Each of them dissipate maximum energy and can withstand a maximum power of 16W without melting. Find the maximum current that can flow through the three resistors.
With the help of a labelled circuit diagram wire describe an activity to illustrate the pattern of the magnetic field lines around a straight current carrying long conducting wire.
(i) Write two observations when lead nitrate is heated in a test tube.
(ii) Name the type of reaction.
(iii) Write a balanced chemical equation to represent the above reaction.
A compound ‘X’ of sodium is used as an antacid and it decomposes on strong heating.
You are provided with 90 mL of distilled water and 10 mL of concentrated sulphuric acid to prepare dilute sulphuric acid.
Two elements X and Y have atomic numbers 12 and 16 respectively. To which period of the modern periodic table do these two elements belong? What type of bond will be formed between them and why? Also give the chemical formula of the compound formed.
(i) Create a terrestrial food chain depicting four trophic levels.
(ii) Why do we not find food chains of more than four trophic levels in nature?
How will you create an artificial aquatic ecosystem, which is self-sustainable?
Explain giving reasons the bending of the shoot tip of a plant towards light source coming from one side of the plant.
It is desired to obtain an erect image of an object, using concave mirror of focal length of 12 cm.
In the figure given below, a narrow beam of white light is shown to pass through a triangular glass prism. After passing through the prism, it produces a spectrum XY on the screen.
(i) What is visible spectrum?
(ii) Why is red used as the stopping light at traffic signals?
(iii) Two triangular glass prisms are kept together connected through their rectangular side. A light beam is passed through one side of the combination. Will there be any dispersion? Justify your answer.
State the reason for the following: Sodium or potassium metals are kept immersed under kerosene.
State the reason for the following: Hydrogen gas is not evolved when most metals react with nitric acid.
State the reason for the following: An iron strip dipped in a blue copper sulphate solution turns the blue solution pale green.
(i) Consider a conductor of resistance ‘R’, length ‘L’, thickness ‘d’ and resistivity ‘ρ’. Now this conductor is cut into four equal parts. What will be the new resistivity of each of these parts? Why?
How does valency of an element vary across a period?
A lens produces a magnification of -0.5. Is this a converging or diverging lens? If the focal length of the lens is 6 cm, draw a ray diagram showing the image formation in this case.
A girl was playing with a thin beam of light from a laser torch by directing it from different directions on a convex lens held vertically. She was surprised to see that in a particular direction, the beam of light continues to move along the same direction after passing through the lens. State the reason for her observation. Draw a ray diagram to support your answer.
On entering in a medium from air, the speed of light becomes half of its value in air. Find the refractive index of that medium with respect to air?
A glass slab made of a material of refractive index n1 is kept in a medium of refractive index n2. A light ray is incident on the slab. Draw the path of the rays of light emerging from the glass slab, if (i) n1 > n2 (ii) n1 = n2 (iii) n1 < n2
On heating blue coloured powder of copper (II) nitrate in a boiling tube, black copper oxide, O2 and a brown gas X is formed.
(a) While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid ?
(b) Dry hydrogen chloride gas does not change the colour of dry litmus paper. Why ?
How is sodium hydroxide manufactured in industries ? Name the process. In this process a gas X is formed as by-product. This gas reacts with lime water to give a compound Y, which is used as a bleaching agent in the chemical industry. Identify X and Y and write the chemical equation of the reactions involved.
List in tabular form three distinguishing features between autotrophic nutrition and heterotrophic nutrition.
What is carpel ? Write the function of its various parts.
A 10 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 12 cm. The distance of the object from the lens is 18 cm. Find the nature, position and size of the image formed.
Write the essential function performed by ozone at the higher levels of the Earth’s atmosphere ? How is it produced ? Name the synthetic chemicals mainly responsible for the drop of amount of ozone in the atmosphere. How can the use of these chemicals be reduced ?
What are solar cells ? Explain the structure of solar panel. List two principal advantages associated with solar cells.
The electrons in the atoms of four elements A, B, C and D are distributed in three shells having 1, 3, 5 and 7 electrons respectively in their outermost shells. Write the group numbers in which these elements are placed in the Modern Periodic Table. Write the electronic configuration of the atoms of B and D and the molecular formula of the compound formed when B and D combine.
List any three observations which posed a challenge to Mendeleev’s Periodic Law.