Science Class X
Explain how, offspring and parents of organisms
Explain how, offspring and parents of organisms reproducing sexually have the same number of chromosomes.
Read more …Give an example of a flower which contains both stamens and carpels
Give an example of a flower which contains both stamens and carpels.
Read more …List Three Techniques To Prevent Pregnancy
List three techniques that have been developed to prevent pregnancy. Which one of these techniques is not meant for males? How does the use of these techniques have a direct impact on the health and prosperity of a family?
Read more …What Is Vegetative Propagation
What is vegetative propagation? State two advantages and two disadvantages of this method.
Read more …What is variation? How is variation created in a population
What is variation? How is variation created in a population? How does the creation of variation in a species promote survival?
Read more …Why does the sun appear reddish early in the morning
Why does the sun appear reddish early in the morning? Will this phenomenon be observed by an astronaut on the Moon? Give reason to justify your answer.
Read more …Noopur needs a lens of power -4.5D for correction of her vision
Noopur needs a lens of power -4.5D for correction of her vision.
- What kind of defect in vision is she suffering from?
- What is the focal length and nature of the corrective lens?
- Draw ray diagrams showing the (a) defected eye and (b) correction for this defect.
- What are the causes of this defect?
Draw a path of light ray passing through a prism
Draw a path of light ray passing through a prism. Label angle of incidence and angle of deviation in the ray diagram.
Read more …State Cause Of Dispersion Of White Light By Glass Prism
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.
Read more …What is presbyopia? State its cause. How is it corrected
What is presbyopia? State its cause. How is it corrected?
Read more …What are magnetic field lines? How is the direction of magnetic field
(a) What are magnetic field lines? How is the direction of magnetic field at a point in a magnetic field determined using field lines?
(b) Two circular coils ‘X’ and ‘Y’ are placed close to each other. If the current in the coil ‘X’ is changed, will some current be induced in the coil ‘Y’? Give reason.
(c) State ‘Fleming’s right hand rule”.
Read more …Draw a labelled diagram of the experimental set up for the study of liberation of carbon dioxide
Draw a labelled diagram of the experimental set up for the study of liberation of carbon dioxide gas during respiration.
Read more …In a school laboratory the students are studying the properties of ethanoic acid
In a school laboratory the students are studying the properties of ethanoic acid through certain experiments. How can they test its acidic nature ? Give two tests.
Read more …In the laboratory of a school, the sample of hard water is not available
In the laboratory of a school, the sample of hard water is not available “to study the comparative cleaning capacity of a sample of soap in soft and hard water”. Which salt from the laboratory can be added to tap water to make it hard ? In the experiment how is cleaning capacity of soap compared ?
Read more …What is a dam? Why do we seek to build large dams
What is a dam? Why do we seek to build large dams? While building large dams, which three main problems should particularly be addressed to maintain peace among local people ? Mention them.
Read more …Students in a school listened to the news read in the morning assembly
Students in a school listened to the news read in the morning assembly that the mountain of garbage in Delhi, suddenly exploded and various vehicles got buried under it. Several people were also injured and there was traffic jam all around. In the brain storming session the teacher also discussed this issue and asked the students to find out a solution to the problem of garbage. Finally they arrived at two main points - one is self management of the garbage we produce and the second is to generate less garbage at individual level.
(a) Suggest two measures to manage the garbage we produce.
(b) As an individual, what can we do to generate the least garbage ? Give two points.
(c) List two values the teacher instilled in his students in this episode.
Read more …If the image formed by a spherical mirror for all positions
If the image formed by a spherical mirror for all positions of the object placed in front of it is always erect and diminished, what type of mirror is it? Draw a labelled ray diagram to support your answer.
Read more …A compound ‘X’ on heating with excess conc. sulphuric acid
A compound ‘X’ on heating with excess conc. sulphuric acid at 443 K gives an unsaturated compound ‘Y’. ‘X’ also reacts with sodium metal to evolve a colourless gas ‘Z’. Identify ‘X’, ‘Y’ and ‘Z’. Write the equation of the chemical reaction of formation of ‘Y’ and also write the role of sulphuric acid in the reaction.
Read more …Write a and b in the given flow chart of neuron
Write a and b in the given flow chart of neuron through which information travels as an electrical impulse.
What is meant by power of a lens
What is meant by power of a lens? Write its SI unit. A student uses a lens of focal length 40 cm and another of –20 cm. Write the nature and power of each lens.
Read more …State the laws of refraction of light
State the laws of refraction of light. Explain the term 'absolute refractive index of a medium' and write an expression to relate it with the speed of light in vacuum.
Read more …Name the hormones secreted by the following endocrine glands
Name the hormones secreted by the following endocrine glands and specify one function of each:
(a) Thyroid (b) Pituitary (c) Pancreas
Read more …Write one main difference between asexual and sexual mode of reproduction
Write one main difference between asexual and sexual mode of reproduction. Which species is likely to have comparatively better chances of survival - the one reproducing asexually or the one reproducing sexually? Give reason to justify your answer.
Read more …Why are alloys commonly used in electrical heating devices
Why are alloys commonly used in electrical heating devices? Give reason.
Read more …Why are metals good conductors of electricity whereas glass is a bad conductor
Why are metals good conductors of electricity whereas glass is a bad conductor of electricity? Give reason.
Read more …List the factors on which the resistance of a conductor
List the factors on which the resistance of a conductor in the shape of a wire depends.
Read more …Why are most carbon compounds poor conductors of electricity?
Why are most carbon compounds poor conductors of electricity?
Read more …2 mL of sodium hydroxide solution is added to a few pieces of granulated zinc
2 mL of sodium hydroxide solution is added to a few pieces of granulated zinc metal taken in a test tube. When the contents are warmed, a gas evolves which is bubbled through a soap solution before testing. Write the equation of the chemical reaction involved and the test to detect the gas. Name the gas which will be evolved when the same metal reacts with dilute solution of a strong acid.
Read more …Decomposition reactions require energy either in the form of heat or light or electricity
Decomposition reactions require energy either in the form of heat or light or electricity for breaking down the reactants. Write one equation each for decomposition reactions where energy is supplied in the form of heat, light and electricity.
Read more …Mention components of blood. Trace the movement of oxygenated blood
(a) Mention any two components of blood.
(b) Trace the movement of oxygenated blood in the body.
(c) Write the function of valves present in between atria and ventricles.
(d) Write one structural difference between the composition of artery and veins.
Read more …Describe in brief the structure and function of placenta
Describe in brief the structure and function of placenta?
Read more …Write the function of following parts in human female reproductive system
Write the function of following parts in human female reproductive system:
- Ovary
- Oviduct
- Uterus
Write the steps involved in the extraction of pure metals
Write the steps involved in the extraction of pure metals in the middle of the activity series from their carbonate ores.
Read more …The modern periodic table has been evolved through the early attempts of Dobereiner, Newland and Mendeleev
(a) The modern periodic table has been evolved through the early attempts of Dobereiner, Newland and Mendeleev. List one advantage and one limitation of all the three attempts.
(b) Name the scientist who first of all showed that atomic number of an element is a more fundamental property than its atomic mass.
(c) State Modern periodic law.
Read more …Write the function of each of the following parts of human eye
Write the function of each of the following parts of human eye:
- Cornea
- Iris
- Crystalline lens
- Ciliary muscles
A student is unable to see clearly the words written on the black board
A student is unable to see clearly the words written on the black board placed at a distance of approximately 3 m from him. Name the defect of vision the boy is suffering from. State the possible causes of this defect and explain the method of correcting it.
Read more …Write the principle of working of an electric motor
Write the principle of working of an electric motor. Explain the function of the following parts of an electric motor:
- Armature
- Brushes
- Split ring
What is observed when a solution of sodium sulphate is added to a solution of barium chloride
What is observed when a solution of sodium sulphate is added to a solution of barium chloride taken in a test tube? Write equation for the chemical reaction involved and name the type of reaction in this case.
Read more …A student added few pieces of aluminium metal to two test tubes
A student added few pieces of aluminium metal to two test tubes A and B containing aqueous solutions of iron sulphate and copper sulphate. In the second part of her experiment, she added iron metal to another test tubes C and D containing aqueous solutions of aluminium sulphate and copper sulphate.
In which test tube or test tubes will she observe colour change? On the basis of this experiment, state which one is the most reactive metal and why.
Read more …An object of height 4.0 cm is placed at a distance of 30 cm
An object of height 4.0 cm is placed at a distance of 30 cm from the optical centre ‘O’ of a convex lens of focal length 20 cm. Draw a ray diagram to find the position and size of the image formed. Mark optical centre ‘O’ and principal focus ‘F’ on the diagram. Also find the approximate ratio of size of the image to the size of the object.
Read more …List the steps of preparation of temporary mount of a leaf peel
List the steps of preparation of temporary mount of a leaf peel to observe stomata?
Read more …Which will have highest concentration of non-biodegradable chemicals
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.
Read more …Why is there a need to harness non-conventional sources of energy
Why is there a need to harness non-conventional sources of energy? Give two main reasons.
Read more …Human beings occupy the top level in any food chain
"Human beings occupy the top level in any food chain." What are the consequences of this on our body?
Read more …Mention difference between Pepsin and Trypsin
Mention any one point of difference between Pepsin and Trypsin.
Read more …How do Mendel’s experiments show that traits may be dominant or recessive
How do Mendel’s experiments show that traits may be dominant or recessive?
Read more …Draw a neat diagram of human brain
Draw a neat diagram of human brain and label Medulla and Cerebellum. Write the functions of the above mentioned parts.
Read more …Page 3 of 4