How do we detect the smell of an agarbatti (incense stick)?
When we lighted an incense stick, then its fragnance diffuses and reaches our nose. which is detected by olfactory receptors. Then, through the sensory neurons these receptors goes in the special part of the brain, i.e, fore- brain :- detect the smell (where it is already stored as a memory), and converts in the form of electrical signals.
When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.
Outline a project which aims to find the dominant coat colour in dogs.
Draw the structure for the following compounds.
(i) Ethanoic acid (ii) Bromopentane*
(iii) Butanone (iv) Hexanal.
*Are structural isomers possible for bromopentane?
A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistance, which may be used separately, in series, or in parallel. What are the currents in the three cases?
How is the sex of the child determined in human beings?
(a) What property do all elements in the same column of the Periodic Table as boron have in common?
(b) What property do all elements in the same column of the Periodic Table as fluorine have in common?
Calculate the number of electrons constituting one coulomb of charge.
What is an homologous series? Explain with an example.
A man with blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits – blood group A or O – is dominant? Why or why not?
Why is variation beneficial to the species but not necessarily for the individual?
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
How is the small intestine designed to absorb digested food?
What processes would you consider essential for maintaining life?
What is an homologous series? Explain with an example.
How is the concentration of hydroxide ions (OH-) affected when excess base is dissolved in a solution of sodium hydroxide?
How is the movement of leaves of the sensitive plant different from the movement of a shoot towards light?
Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?
What are the methods used by plants to get rid of excretory products?
How is the amount of urine produced regulated?
Write a balanced chemical equation with state symbols for the following reactions: