### List

### A convex mirror used on automobile has 3 m radius of curvature. If a bus is located at 5m from this mirror, find the position and size of the image

### What happens when is heated in the absence of oxygen?

### What happens when nitric acid is added to an eggshell?

### You are given three test tubes. These three test tubes contain distilled water, acidic and basic solutions, respectively. Only red litmus paper is available to identify what is there in each test tube. How will you separate what is in each of the three test tubes?

### Equal lengths of magnesium ribbons are taken in test tubes A and B. Hydrochloric acid (HCl) is added to test tube A, while acetic acid (CH3COOH) is added to test tube B. Amount and concentration taken for both the acids are equal. In which test tubes A and B will the fizzing occur intensely and vigorously. Give reasons.

### What is a neutralisation reaction? Give two examples.

### Explain why Plaster of Paris should be stored in a moisture-proof container. Give reasons.

### Why does an aqueous solution of acid conduct electricity?

### Name the sodium compound used to soften hard water.

### Which gas is generally liberated when an acid reacts with a metal? Illustrate with a suitable ex. How will you identify and test for the presence of this gas?

### What is the exact chemical formula of POP?

### Why does distilled water not conduct electricity, whereas rainwater does?

### Bleaching powder forms a milky solution in water. Explain.

### Why do we store silver chloride in dark-coloured bottles?

### Dissolving sugar is an example of which change-1 Physical change 2.Chemical change 3. Redox Reaction 4. None of these.

### What is suspension?

### What is the difference between a solution and mixture?

### What is the general name of the materials which contain at least two pure substances and show the properties of their constituents?

### What is meant by saying that nonmetals are brittle?

### You can classify seawater as both a homogeneous and heterogeneous mixture. Comment.

### What do you mean by the pure substance.

### What is a saturated solution?

### What is a colloid? What are its different properties?

### Can matter change its state?

### What are the conditions for “something” to be called matter?

### Naphthalene balls vanish with time, leaving no solid. Explain.

### We observe no change in volume of water when we dissolve a specific amount of salt/sugar into a given volume. This observation illustrates which characteristic of matter?

### Gases can be substantially compressed but liquids cannot be compressed much. Why?

### Divers can cut through the water in a swimming pool. What property of matter does this observation prove?

### Solve the equation 4x²+9 = 0

### Prove that Sin²60 + cos²60- tan² 60 = - 2

### It is a hot summer day Priyanshi and Ali are wearing cotton and nylon clothes respectively. Who do you think would be more comfortable and why?

### The melting points of three solids X, Y and Z are 298K, 310K and 400K, respectively. Arrange these in increasing order of their inter-particle force of attraction.

### Explain why, osmosis can be considered to be a special kind of diffusion.

### Classify the following into osmosis/diffusion ."Spreading of the virus through sneezing"

### Spreading of the virus through sneezingis diffusion or osmosis? .

### Give reasons. Raisins soaked in water swell up after some time.

### Classify the following into osmosis/diffusion. Aquatic animals using oxygen dissolved in water during respiration.

### What is sublimation?

### What is boiling point of water on kelvin scale?

### Name two processes which provide the best evidence for the motion of particles in matter.

### Convert 359k

### How does perspiration /sweating help keep our body cool ?

### Why does the temperature remain constant during change of state of matter even though heat is supplied continuously?

### Gases have high compressibility why?

### How many types of indicators are there?

### What are the common indicators of acids and bases?

### Define acid.

### Define indicator.

### What are different properties of acid.?

### If one AM ‘a’ and two GM’s p and q are inserted between any two given numbers then find value of 2A

### If the sum of first two terms of an infinite GP is 1 and every term is twice the sum of all the successive terms, then find its first term ?

### If a,b,c, are in G.P. and x,y respectively arithmetic means between a,b and b,c then prove that1/x +1/y =2/b

### Why acid is add to water not water to acid ?

### Why is dilute acid added to water during electrolysis?

### The nth term of a G.P. is 128 and the sum of its n terms is 255. If its common ratio is 2, then find first term .

### The sum of an infinite number of terms of a G.P. is 4 , and the sum of their cubes is 192 ; find the series.

### In a set of four numbers the first three are in G . P . and the last three in A . P . with common difference 6 . If the first number is the same as the fourth, find the four numbers.

### How much work is done in moving a charge of 2C across two points having a potential difference of 12V?

### What is resistance in electricity

### Define the term volt.

### What is electric difference.

### What is potential difference and its SI unit?

### Define electric current. What is its S I unit?

### What is the definition of 1 ampere

### Define 1 Coulomb

### An object has moved through a distance. Can it have zero displacements?

### Differentiate between uniform and non-uniform motion. Give examples.

### Define lateral displacement.

### How do convex mirrors diverge?

### Why is a concave mirror called a converging mirror?

### For which value(s) of k would the pair of given equations kx + 3y = k – 3, 12x + ky = k have no solution?

### Why is a concave mirror used in a solar cooker?

### Which type of mirror is used in a solar furnace?

### Which mirror is used in dentists?

### Which mirror is used as shaving mirror and why ?

### Which mirror is used in rear mirror ?

### Why all decomposition reactions are endothermic reaction?

### Where is hydrogen formed in electrolysis of water?

### A sample of water under study was found to boil at 102 ℃ at normal temperature and pressure. Is the water pure? Will this water freeze at 0 ℃? Comment

### How can a gas be liquefied

### How does perspiration or sweating help keep our body cool on a hot day?

### What is pepsin?

### What is the main component of gastric juice?

### How are fats digested in our body ?

### Which enzyme digests fat?

### How are fats proteins and carbohydrates digested in the body?

### How is oxygen and carbon dioxide transported in human body?

### Where do plants get each of the raw materials for photosynthesis?

### What are the essential life processes?

### What Is the Role of Acid in Our Stomach?

### Why does steam cause more severe burns?

### Which has more energy steam or hot water?

### What is the hidden energy heat?

### Why does water at 0°c have more energy than ice at the same temperature?

### Why gases are compressible but not liquids ?

### Write the various steps of photosynthesis ?

### Where do plants get their oxygen for cellular respiration ?

### Write down short note on excretion in plants.

### How do leaves of plants help in excretion?

### What do you mean by ATP and ADP ?

### How many irrational numbers lie between √ 2 and √ 3 ? Find any three irrational numbers lying between √ 2 and √ 3

### Find a rational number and also an irrational number lying between the numbers 0.3030030003 ... and 0.3010010001 ...

### Linux for beginners - Commands & Explanation

### “All plants give out oxygen during the day and carbon dioxide during the night only”. Do you agree with this statement? Give reason

### What is the end product of carbohydrates fats and proteins

### Bile juice contains no digestive enzymes, yet it is important for digestion. Why?

### What is the role of saliva in digestion of food ?

### Name the enzyme present in human saliva. What type of food material is digested by this enzyme ?

### From which part of the body, undigested food is egested in Amoeba?

### What is Nutrition? Name the two main modes of nutrition and define them.

### What do you mean by life processes?

### When 3 is added to the denominator and 2 is subtracted from the numerator a fraction becomes 1 /4 . And, when 6 is added to numerator and the denominator is multiplied by 3 , it becomes 2 /3 . Find the fraction.

### Two places A and B are 120 km apart from each other on a highway. A car start from A and another from B at the same time. If they move in same direction, they meet in 6 hours and if they move in opposite directions they meet in 1 hour and 12 minutes. Find the speeds of the car.

### If sin θ and cos θ are the roots of the equation a x ²− b x + c = 0 , then prove that a²-b²+2ac=0

### If the roots of the equation ( a − b ) ² + ( b − c ) ² + ( c − a )² = 0 are equal, prove that 2 a = b + c .

### The difference of two natural numbers is 5 and the difference of their reciprocals is 5 /14 . Find the numbers.

### If an odd number p divides q2 then it will divide q3 also?? Explain

### Weite the HCF and LCMof the smallest odd composite number and the smallest odd prime number.

### The product of the LCM and HCF of two numbers is 24. The difference of the two numbers is 2. Find the numbers.

### Prove that √ 3 is an irrational number

### Show that 3 + 5 √ 2 is an irrational number. Is sum of two irrational numbers always an irrational number?

### Show that 4n can never end with the digit zero for any natural number n.

### There are 104 students in class X and 96 students in class IX in a school. In a house examination, the students are to be evenly seated in parallel rows such that no two adjacent rows are of the same class. (a) Find the maximum number of parallel rows of each class for the seating arrange¬ment. (b) Also, find the number of students of class IX and also of class X in a row.

### The LCM of two numbers is 14 times their HCF. The sum of LCM and HCF is 750. If one number is 250, then find the other number.

### Find the greatest number of 5 digits exactly divisible by 9,12,15,18 and 24.

### Ravi, Seema, and Raju start preparing cards for all persons in an old age home. They complete one card in 20, 16 and 10 minutes. If all of them started together at the same time, after what time will they start preparing a new card together?

### Avi has two vessels, which contain 720 ml and 405 ml of the milk, respectively. Milk from these containers is poured into the glasses of equal capacity to their brim. Thus, Find the minimum number of glasses that can be filled.

### There is a circular path around a sports field. Shilpa takes 18 minutes to drive one round of the field, while Rahul takes 12 minutes for the same path. Suppose both of them start at the same point and at the same time and go in the same direction. After how many total minutes will both meet again at the starting point?

### Given that HCF (306, 657) = 9, find LCM (306, 657).

### Find the largest number, which divides 70 and 125, leaving remainders 5 and 8 respectively

### If HCF of 65 and 117 is expressible in form 65m– 117, then find m

### The length, breadth and height of a room are 825 cm, 675 cm and 450 cm respectively. Find the longest tape which can measure the three dimensions of the room exactly.

### What is the HCF of the smallest prime number and the smallest composite number?

### Name the glands associated with the digestion of carbohydrates in the human alimentary canal and mention their role ?

### Name the glands associated with digestion of starch in human digestion track. Mention their role? How is required pH maintain and stomach intestine?

### Which organisms show single circulation?

### "The breathing cycle is rhythmic whereas exchange of gases is a continuous process". Justify this statement.

### What is difference between Monohybrid and Dihybrid.

### What is difference between Homozygous and Hetrozygous

### What is the difference between dominant and recessive traits?

### Name some unicellular organisms in which all life-processes take place within their unicellular body.

### Explain the various steps of nutrition in animals.

### What is meant by parasitic plants ? Name their different types with examples of each.

### Why do living organisms need nutrition ?

### How is digested food is used?

### An electric kettle consumes 1 KW of electric power when operated at 220 V. A fuse wire of what rating must be used for it?

### Question What is meant by solenoid? How does a current carrying solenoid behave? Give its main use.

### Why is transpiration called a necessary

### Why are lungs divided into very small sac like structure?

### Why does the colour of copper sulphate solution change when an iron nail is kept immersed in it

### What is internal energy reserve in plants do the animals have the same energy reserve justify?

### Is respiration an exothermic reaction

### What is difference between electric potential and potential difference?

### Why are copper and aluminium wires usually employed for electricity transmission?

### What happens when Znco3 is heated in absence of air?

### Which gas is usually liberated when an acid reacts with a metal?

### A crane pulls up a car of mass 500 k g to a vertical height of 4 m . Find work done by the crane .

### What is food chain ? How does the study of food chain in an area or habitat help us ? Give an example of four-step food chain operating in a large lake.

### What the type of reaction taking place when water is added slowly to a small amount of calcium oxide in a beaker .

### What plant hormone causes seeds to germinate?

### A train starting from rest attains a velocity of 72 km/h in 5 minutes. Assuming that the acceleration is uniform, find the acceleration and the distance travelled by train for attaining this velocity.

### Name the three types of plastids and state one function of each.

### What do you mean by plastic?

### Why lysosomes are known as scavengers of the cell?

### How will you decide whether the magnetic field at a point is due to some current carrying conductor or due to earth?

### Where does the fertilization occur in reproductive system?

### What do you mean by internal respiration?

### How many eggs are typically produced by each ovary of non-pregnant women each year?

### To which category did diseses AIDS belong ? name its causitive organism

### How do harmful chemicals get accumulated progressively.

### Explain why sodium hydroxide solution cannot be kept in aluminum containers .

### What are the rules of inheritance?

### At ordinary temperature the surface of metals, such as magnesium, aluminium, zinc, lead etc. do not undergo oxidation. Give reason.

### Why do plant cells possess large sized vacuole?

### If you are provided with some vegetables to cook. You generally add salt to the vegetables during the cooking process. After adding salt, vegetables release water. What mechanism is responsible for this?

### A person takes concentrated solution of salt. After sometime he starts vomiting. What is the phenomenon responsible for such a situation?

### How does an Amoeba obtain its food?

### Where are proteins synthesized inside the cell?

### Bacteria do not have chloroplast but some bacteria are photoautotrophic in nature and perform photosynthesis. Which part of the bacterial cell performs this?

### Why simple diffusion is enough for performing various life processes in unicellular organisms and why not in multicellular organisms?

### A student boils the water in an electric kettle for 20 minutes after being switched on. If the boiling time is to be decreased then what should be the length of the heating element ?

### A compass needle gets deflected when brought near a bar magnet because the needle of a compass is a magnet, which experiences a magnetic field exerted by the bar magnet.

### How many times AC current change its direction in one second.

### AC or DC – Which One is More Dangerous And Why ?

### What is difference between AC and DC

### A cone, a hemisphere and a cylinder stand on equal bases and have the same height. The ratio of their volumes is 1 : 2 : 3. Is the given statement true or false and justify your answer.

### Prove that Sec A (1-sin A)(sec A+ tan A) = 1

### A person is listening to a tone of 500 Hz sitting at a distance of 450 m from the source of the sound. What is the time interval between the successive compression from the source?

### A copper rod of diameter 1 cm and length 18 m is drawn into a wire of length 18 m of uniform thickness. Find the thickness of the wire.

### A cone of height 24cm and radius of base 6cm is made up modelling clay. A child moulds it in the form of sphere. Find the radius of the sphere.

### Why are asexually reproducing organisms capable of showing hereditary features ?

### Why are males called heterogametic?

### Is it true that when a new species is emerged, the old species is eliminated and why?

### When a monochromatic light having only one wavelength, passes through a prism, will it show dispersion?

### A squirrel is in a scary situation. Its body has to prepare for either fighting or running away. State the immediate changes that take place in its body so that the squirrel is able to either fight or run?

### Define the Right-Hand Thumb Rule for determining the direction of the magnetic field around a straight current-carrying conductor.

### There are two small boxes A and B . In A there are 9 white beads and 8 black beads. In B there are 7 white and 8 black beads. We want to take a bead from a box. (a) What is the probability of getting a white bead from each box? (b) A white bead and a black bead are added to box B an then a bead is taken from it. What is probability of getting a white bead from it.

### hat are 5 uses of isotopes?

### What is the new resistance of a wire of resistance R is doubled on itself?

### There are two covers A and B; each containing paper slips with natural numbers from 1 to 7 written on them. One slip is drawn from each cover. Using them, a two digit number is formed with a number from A in the units place and the number from B in the tens place. How many such two digit numbers can be formed? What is the probability that a two digit number so formed is even?

### One of the two students while solving a quadratic equation in x copied the constant term incorrectly and got the roots 3 and 2. The other copied the constant term and coefficient of x ² correctly as -6 and 1 respectively. What are the correct roots .

### A thick and thin wire made ftom same material and of same length are connected one by one to same source. in which case a large current will flow in circuit? justify your answer?

### Why is an electric fuse required in all electrical appliances?

### Why is an ammeter connected in series in an electric circuit?

### How is ammeter and voltmeter connected in a circuit ?

### Why does the cord of an electric heater not glow while the heating element does

### Why are copper and aluminium wires usually used for electricity transmission ?

### What is the reason for using Tungsten as a filament in electric bulb?

### Why is the series arrangement not used-for domestic circuits?

### When a sound is reflected from a distinct object, an echo is produced. Let the distance between the reflecting surface and the source of sound production remains the same. Do you hear echo sound on a hotter day?

### Does sound follow the same laws of reflection as light does? Explain.

### Suppose you and your friend are on the moon. Will you be able to hear any sound produced by your friend?

### Why are sound waves called mechanical waves?

### Why is the ceiling and wall behind the stage of good conference halls or concert halls made curved?

### If any explosion takes place at the bottom of a lake, what type of shock waves in water will take place ?

### Why are we able to hear the sound produced by the humming bees while the sound of vibrations of the pendulum is not heard ?

### Are the physical and chemical properties of isobars similar ?

### Define isobar.

### Summarise the rules for writing of distribution of electrons in various shells for the first eighteen elements.

### Why helium neon and argon has zero vacancy?

### How do you define reverberation of sound? Suggest some steps to reduce the reverberation.

### What is composite fish culture? What are the advantages of composite fish culture?

### During heavy rains in a village ,the rain water carried excessive nitrogen compounds to a pond. How will it affect the growth of fish in the pond in the long run?

### What are the differences between mixed cropping and intercropping?

### What are functions of chromoplast.

### The shorter the duration of crop the more economical the variety. Justify the statement

### In agricultural practices, higher input gives higher yield. Discuss how

### Prove that √ 5 − √ 3 is not a rational number.

### Prove that 6 + √ 2 is irrational

### Explain why are the conductors of heating devices like toaster are made of an alloy?

### Why is ice rubbed on a burnt part of the skin?

### On a hot sunny day, why do people sprinkle water on the roof or open ground?

### Why can we easily move our hands in the air but do the same through a plank of wood, we need a karate expert? Explain.

### Why is ice at 0 o C more effective in cooling than water at 0 o C?

### What is common between the three states of matter

### Why does perspiration leave a cooling effect on our body?

### Explain why temperature remain constant during the change of state of any substance?

### On selling a T . V . at 5 % gain and fridge at 10 % gain, a shopkeeper gains R s . 2000 . But if he sells the T . V . at 10 % gain and the fridge at 5 % loss. He gains R s . 1500 on the transaction. Find the actual prices of T . V . and fridge.

### What is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?

### How is the equal genetic contribution of male and female parents ensured in the progeny?

### What could be the reasons for adopting contraceptive methods?

### How does reproduction help in providing stability to population of a species?

### What is the difference between the manner in which movement takes place in a sensitive plant and the movement in our legs?

### How are involuntary actions and reflex actions different from each other?

### What would be the consequences of the deficiency of haemoglobin in the human body?

### What are the necessary conditions for autotrophic nutrition and what are its by-products?

### Nervous and hormonal systems together perform the function of control and coordination in human beings." Justify the statement.

### Can you think of any reasons why more complex organisms cannot give rise to new individuals through regeneration?

### Why is the flow of signals in a synapse from axonal end of one neuron to dendritic end of another neuron but not the reverse?

### How does chemical coordination take place in animals?

### Describe reflex action and reflex arc

### What is the difference between pollination and fertilization?

### Explain, “Regeneration is not the same as reproduction”

### Why are the petals colourful and why does the flower smell nice

### In a bisexual flower inspite of the young stamens being removed artificially, the flower produces fruit. Choose a suitable explanation for the above situation.

### Water as ice has a cooling effect, whereas water as steam may cause severe burns. Explain this observation.

### How does the water kept in an earthen pot (matka) become cool during summer?

### How do the three states of matter arise

### Why it is advisable to use pressure cooker at high altitude?

### Why do you feel cold after your morning exercise?

### A balloon kept in the sun will burst after some time.

### Find the length of the longest rod that can be placed in room 12 m wide and 8 m high.

### Curved surface area of a cone. is 308 c m 2 its slant height is 14 c m . Find radius of the base

### A hemispherical bowl has a radius of 3.5 cm. What would be the volume of water it would contain?

### A dome of a building is in the form of a hemisphere. From inside, it was white-washed, at the cost of Rs. 498.96 . If the cost of white-washing is R s . 2.00 per square metre, find the

(i) inside surface area of the dome

(ii) volume of the air inside the dome.### A corn cob, shaped somewhat like a cone, has the radius of its broadest end as 2.1 c m and length (height) as 20 c m . If each 1 c m 2 of the surface of the cob carries an average of four grains, find how many grains (approximately) you would find on the entire cob.

### The radius of a spherical balloon is inflated from 1.5 c m to 2.5 c m by pumping more air in it. Find the ratio of surface area of resulting balloon to the original balloon.

### All the vertices of a rhombus lie on a circle. Find the area of rhombus,if the area of circle is 1256 cm²

### The perimeter of a parallelogram ABCD = 40 cm, AB = 3x cm, BC = 2x cm and CD = 2(y +1) cm. Find the values of x and y.

### In a parallelogram PQRS, PQ = 10 cm. The altitude corresponding to the sides PQ and SP are respectively 6 cm and 8 cm. Find SP

### If angle of parallelogram is four-fifths of its adjacent angle, then find the angles of parallelogram.