What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise?
Receptors are transducers which exhibits sensitivity in various body parts. When our body receives any external or internal stimuli, it converts stimuli into nerve impulses (action potential) and send these impulses to other neurons, muscle fibres or glands.
If the receptors get damaged they will not detect the stimulus, as well our brain also will not detect the signals which will be harmful for our body (Eg. When we touch an cold or hot object or to getting burnt etc.)
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.
Why is variation beneficial to the species but not necessarily for the individual?
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?
Which of the following pairs will give displacement reactions?
(a) NaCl solution and copper metal
(b) MgCl2 solution and aluminium metal
(c) FeSO4 solution and silver metal
(d) AgNO3 solution and copper metal.
What is meant by power of accommodation of the eye?
How can ethanol and ethanoic acid be differentiated on the basis of their physical and chemical properties?
What criteria do we use to decide whether something is alive?
Explain the meanings of malleable and ductile.
Outline a project which aims to find the dominant coat colour in dogs.
A convex lens forms a real and inverted image of a needle at a distance of 50 cm from it. Where is the needle placed in front of the convex lens if the image is equal to the size of the object? Also, find the power of the lens.
Why do you think the noble gases are placed in a separate group?
How do we detect the smell of an agarbatti (incense stick)?
Why does dry HCl gas not change the colour of the dry litmus paper?