Outline a project which aims to find the dominant coat colour in dogs.
Dogs have different coats. In order to find dominant coat (hair) colour in dogs, select a pure- bred of male and female dog having black colour or pure- bred of male and female having brown colour. Cross the homozygous male BB and homozygous female bb, and then observe the coat colour in dog progeny (offspring). If all progeny have black colour, this means that black colour will be the dominant coat colour in dogs and if progeny will have brown colour then the brown colour will be dominant coat colour.
And, by making the punnett square of F1 generation, we will get Bb, Bb, Bb, Bb ,i.e, all progeny are showing the black colour. So, it is concluded that the dominant colour is black.
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.
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?
Give an example of a metal which
(i) is a liquid at room temperature.
(ii) can be easily cut with a knife.
(iii) is the best conductor of heat.
(iv) is a poor conductor of heat.
What are the advantages and disadvantages of using a solar cooker? Are there places where solar cookers would have limited utility?
What are amphoteric oxides? Give two examples of amphoteric oxides.
What is the principle of an electric motor?
Can the wing of a butterfly and the wing of a bat be considered homologous organs? Why or why not?
What is the role of decomposers in the ecosystem?
Why is the amount of gas collected in one of the test tubes in Activity 1.7 double of the amount collected in the other? Name this gas.
Plaster of Paris should be stored in a moisture-proof container. Explain why?
What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
Explain the underlying principle and working of an electric generator by drawing a labelled diagram. What is the function of brushes?
How can you help in reducing the problem of waste disposal? Give any two methods.