What is meant by the 'calorific value' of a fuel? How is it determined? Arrange the following fuels in a decreasing order of their calorific values: Kerosene, Coal, LPG.

Lithium, sodium and potassium form a Dobereiner's triad. The atomic masses of lithium and potassium are 7 and 39 respectively. Predict the atomic mass of sodium.

When Mendel crossed a tall plant with a dwarf plant, no medium height plants were obtained in F₁ generation. Why?

Study the diagram and answer the questions following it.

a) Which defect of vision is represented in this case? Give the 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.

What are the advantages and disadvantages of using a solar cooker? Are there places where solar cookers would have limited utility?

Unsaturated hydrocarbons contain multiple bonds between the two C-atoms and show addition reactions. Give the test to distinguish ethane from ethene.

List two advantages of vegetative reproduction practised in case of an orange plant.

How is the sex of a newborn determined in humans?

What is lens formula? Give its sign conventions and assumptions.

Differentiate myopia and hypermetropia.

Give reasons for the following:
(i)The glottis is guarded by epiglottis
(ii)The lung alveoli are covered with blood capillaries.
(iii)The wall of trachea is supported by cartilage rings.

Give difference between nervous system and endocrine system.

Distinguish between permanent magnet and electromagnet.

(a) State one limitation of solar energy available from solar cells.
(b) What is the minimum wind velocity required to obtain useful energy with a windmill?
(c) Define the term 'nuclear fission'.

(i) Define universal indicator. For what purpose it is used?
(ii) Two solutions A and B have pH values of 3.0 and 9.5 respectively. Which of these will turn litmus solution from blue to red and which will turn phenolphthalein from colourless to pink?
(iii) Water is a neutral substance. What colour will you get when you add a few drops of the universal indicator to a test tube containing distilled water?

(a)Draw a diagram of human 'alimentary canal'.
(b)Label the following on the diagram drawn: Oesophagus, Liver, Gall bladder, Duodenum
(c)What is the function of liver in the human body?

Explain why carbon forms compounds mainly by covalent bond. Explain in brief two main reasons for carbon forming a large number of compounds. Why does carbon form strong bonds with most other elements?

An element is placed in 2nd Group and 3rd Period of the Periodic Table, burns in presence of oxygen to form a basic oxide.
(a) Identify the element.
(b) Write the electronic configuration.
(c) Write the balanced equation when it burns in the presence of air.
(d) Write a balanced equation when this oxide is dissolved in water.
(e) Draw the electron dot structure for the formation of this oxide.

(a) In question 8, what are the combinations of character in the F₂ progeny?
(b) What are their ratios?

(a)What are the values of (i)near point and (ii)far point of vision of a normal adult person?
(b)A student has difficulty in reading the blackboard while sitting in the last row.What could be his defect of vision?Draw a ray diagram to illustrate this defect of vision

Classify the ecological pyramids.

In the context of conservation of natural resources, explain the terms reduce, recycle and reuse. From among the materials that we use in daily life, identify two materials for each category.