List five things you have done over the last one week to —
(a) conserve our natural resources.
(b) increase the pressure on our natural resources.
(a) Five things are following that i have done to conserve our natural resources over the last one week:-
1. I carried paper bags and jute bags while leaving the house for the shopping or for taking vegetables etc.
2. I preferred walking or bicycle to cover short distances instead of going on scooty or automobile appliances.
3. I switched off my rooms or house lights, fans, television which was unnecessarily on.
4. I used pencils for the rough work so that paper can be used again and again.
5. I stopped the tap while brushing the teeth or stopped taking shower and i filled bucket to save water for bathing.
(b) For increasing the pressure on our natural resources, the list of five things which i have done over the last one week are following:-
1. I played video games for the whole day.
2. I forgot to switch off the lights of my bedroom while leaving the room.
3. I threw plastic that is non- biodegradable on the roads.
4. I made paper boats during the rain and play with them.
5. I also forgot to switch off the charger point and left my phone on charging for the whole night which is the wastage of electricity or this can also damage our mobile phones.
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?
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?
How can ethanol and ethanoic acid be differentiated on the basis of their physical and chemical properties?
(a) Lithium, sodium, potassium are all metals that react with water to liberate hydrogen gas. Is there any similarity in the atoms of these elements?
(b) Helium is an unreactive gas and neon is a gas of extremely low reactivity. What, if anything, do their atoms have in common?
How do we detect the smell of an agarbatti (incense stick)?
What are the qualities of an ideal source of energy?
Which gas is usually liberated when an acid reacts with a metal? Illustrate with an example. How will you test for the presence of this gas?
The change in focal length of an eye lens is caused by the action of the
(a) pupil. (b) retina.
(c) ciliary muscles. (d) iris.
A person with a myopic eye cannot see objects beyond 1.2 m distinctly. What should be the type of the corrective lens used to restore proper vision?
Why do we apply paint on iron articles?
Why does the Sun appear reddish early in the morning?