"Improvements in our lifestyle have resulted in greater amounts of waste generation." Give two examples to support the given statement. Suggest one change that we can incorporate in our lifestyle in order to reduce non biodegradable waste.
The following organisms form a food chain.
Insect, Hawk, Grass, Snake, Frog
Which of these will have highest concentration of non-biodegradable chemicals? Name the phenomenon.
Why is there a need to harness non-conventional sources of energy? Give two main reasons.
"Human beings occupy the top level in any food chain." What are the consequences of this on our body?
With the help of a labelled circuit diagram wire describe an activity to illustrate the pattern of the magnetic field lines around a straight current carrying long conducting wire.
i) Name the rule that is used to find the direction of magnetic field associated with a current carrying conductor.
ii) Is there a similar magnetic field produced around a thin beam of moving (a) alpha particles and (b) neutrons? Justify your answer.
Draw a circuit diagram of an electric circuit containing a cell, a key, an ammeter, a resistor of 4Ω in series with a combination of two resistors (8Ω each) in parallel and a voltmeter across parallel combination. Each of them dissipate maximum energy and can withstand a maximum power of 16W without melting. Find the maximum current that can flow through the three resistors.
Name the electric device that converts mechanical energy into electrical energy. Draw the labelled diagram and explain the principle involved in this device.
State the cause of dispersion of white light by a glass prism. How did Newton, using two identical glass prisms, show that white light is made of seven colours? Draw a ray diagram to show the path of a narrow beam of white light, through a combination of two identical prisms arranged together in inverted position with respect to each other, when it is allowed to fall obliquely on one of the faces of the first prism of the combination.
Noopur needs a lens of power -4.5D for correction of her vision.
a) What kind of defect in vision is she suffering from?
b) What is the focal length and nature of the corrective lens?
c) Draw ray diagrams showing the (a) defected eye and (b) correction for this defect.
d) What are the causes of this defect?
Rohit focused the image of a candle flame on a white screen using a convex lens. He noted down the position of the candle, screen and lens as under:
Position of candle = 26.0 cm
Position of convex lens = 50.0 cm
Position of screen = 74.0 cm
i) What is the focal length of the convex lens?
ii) Where will the image be formed if he shifts the candle towards the lens at a position of 38 cm?
iii) Draw a ray diagram to show the formation of the image in case (ii) as said above?
An object of height 1.2 m is placed before a concave mirror of focal length 20 cm so that a real image is formed at a distance of 60 cm from it. Find the position of an object. What will be the height of the image formed?
Give an example of a flower which contains both stamens and carpels.
Explain the ways in which glucose is broken down in absence of oxygen.
How do Mendel’s experiments show that traits may be dominant or recessive?
"Both overproduction and underproduction of Growth hormone leads to disorders in the body." Explain
With the help of one example for each, distinguish between the acquired traits and the inherited traits. Why are the traits / experiences acquired during the entire lifetime of an individual not inherited in the next generation? Explain the reason of this fact with an example.
How did Mendel explain that it is possible that a trait is inherited but not expressed in an organism?
Distinguish between esterification and saponification reactions with the help of the chemical equations for each. State one use of each (i) esters, and (ii) saponification process.
Write the number of periods and groups in the Modern Periodic Table. How does the metallic character of elements vary on moving (i) from left to right in a period, and (ii) down a group? Give reason to justify your answer.
Na, Mg and Al are the elements of the 3rd period of the Modern Periodic Table having group number 1, 2 and 13 respectively. Which one of these elements has the (a) highest valency, (b) largest atomic radius, and (c) maximum chemical reactivity? Justify your answer stating the reason for each.
Why are certain compounds called hydrocarbons? Write the general formula for homologous series of alkanes, alkenes and alkynes and also draw the structure of the first member of each series. Write the name of the reaction that converts alkenes into alkanes and also write a chemical equation to show the necessary conditions for the reaction to occur.
Suggest different chemical processes used for obtaining a metal from its oxides for metals in the middle of the reactivity series and metals towards the top of the reactivity series. Support your answer with one example each.
You are given balls and stick model of six carbon atoms and fourteen hydrogen atoms and sufficient number of sticks. In how many ways one can join the models of six carbon atoms and fourteen hydrogen atoms to form different molecules of C6H14.
Draw the structural formulae of all the possible isomers of the compound with the molecular formula C3H6O and also give their electron dot structures.
An element "X" has mass number 35 and the number of neutrons is 18. Identify the group number and period of "X".
Differentiate between the arrangement of elements in Mendeleev’s periodic table and Modern periodic table.
A compound which is prepared from gypsum has the property of hardening when mixed with a proper quantity of water. Identify the compound and write its chemical formula. Write the chemical equation for its preparation. Mention any one use of the compound.
In a given ammeter, a student sees that needle indicates 17 divisions in ammeter while performing an experiment to verify Ohm’s law. If ammeter has 10 divisions between 0 and 0.5A, then what is the value corresponding to 17 divisions?
A student conducted an experiment to show CO2 is released during respiration. List two precautions that he or she must take for obtaining correct observations.
A student observed a permanent slide showing asexual reproduction in yeast. Draw diagrams of the observations he must have made from the slide. Name the process also.
Riya performs two set of experiments to study the length of the foam formed which are as follows:
Set I: she takes 10 ml of distilled water in test tube “A” and adds 5-6 drops of liquid soap in it and shakes the test tube vigorously.
Set II: she takes 10 ml of distilled water in a test tube “A” and adds 5-6 drops of liquid soap with half spoonful of CaSO4 in it and shakes the test tube.
Write your observation and reason.
What do you observe when you drop a few drops of acetic acid to a test tube containing:
a) Phenolphthalein c) distilled water
b) Universal indicator d) sodium hydrogen carbonate