IMPORTANT QUESTIONS OF BIO CH-1

Q1(a) Explain with the help of diagram, how amoeba takes its nutrition.
(b) Assume that you are a veterinary surgeon and you had removed a
 good length of the small intestine of a bear that was suffering from a
intestinal tumor. Now, would you suggest a plant based or an meat
based diet for the bear after its recovery ? Give reason for your answer
ans1(a)



(b)I would suggest meat based diet because small intestine can easily
absorb it but plants contain cellulose which is not easy to be absorbed.
Q2(a)Draw the diagram of human heart and label it.
 (b) Which blood vessel  carries away oxygenated blood from the heart
(c) Which blood vessel receives de-oxygenated blood from the lower part
 of our body.
ans2(a)


(b)Aorta
(c)Vena Cava of lower body
Q3(a)The stomatal opening is controlled by guard cells. If the stomatal
opening is to remain open how should the guard cells be ?
(a) stretched (b) swollen (c) rigid (d) shrunk
Ans3-(b)Swollen
Q4(a) Draw the human respiratory system and label it.
 (b) During breathing cycle what is the advantage of residual volume of air
 in lungs ? Explain.
ans4(a)

(b)During the breathing cycle,the lungs always have a residual volume of gases
so that there is sufficient time  for oxygen to be absorbed and carbondioxide
to be released.
Q5-Other than light, which of the following are also essential for photosynthesis ?
(a) carbon di-oxide, water, chlorophyll (b) carbon di-oxide, chlorophyll
(c) carbon, water, minerals, chlorophyll (d) carbon di-oxide, water, hormones
ans-(a)
Q6The guard cells are also capable of photosynthesis because they have :
 (a) cytoplasm, nucleus, centrioles (b) cytoplasm, nucleus, centrosome
(c) cytoplasm, nucleus, chromosomes (d) cytoplasm, nucleus, chloroplasts
Ans6-(d)
Q7 Explain why ventricles have thick muscular walls than the atria ?
Ans-Ventricles have thick muscular walls than atria because
Q8(a) Define excretion. Name any two substances that are selectively
reabsorbed. (b) Draw and label the human excretory system.
ans8-(a)The biological process of the removal of harmful metabollic
wastes from the  body is called excretion.Glucose,amino acids,salts
and water are re-absorbed.
(b)
 

Q9In human alimentary canal name the site of complete digestion of
various components of food. How?
Ans9-The site of comlete digestion in human alimentary canal is the
small intestine.It recieves the secretions of the liver and pancreas
for this purpose.The food coming from the stomach is acidic and
has to be made alkaline for pancreatic enzymes to act.Bile juice
 from the liver acts on the fats.The Bile salt acts upon the fat globules
and helps enzymec to act upon them.Pancreatic enzymes like trypsin
act upon protiens and lypase on the fats.The protiens are converted
into amino acid, carbohydrates into glucose and fats into fatty acids
and glycerol.The inner lining of the small intestine has villi which
increase the surface area of absorption.The blood vessels in it take
 up the absorbed  food and distributed in the body.
Q10-Explain the process of nutrition.
Ans10-
1.Firstly we take in food through mouth and crush it and mix
it with saliva as the food  pipe is muscular and soft.The salivary
amylase,an enzyme,break down the starch.The food now passes
through oesophagus by peristaltic movements.
2.The food reaches the stomach.The walls of the stomach help
in digesting foofd by mixing it with digestive juices.The gastic
glands in the stomach release HCl ,protien digesting enzyme pepsin
and mucus.Pepsin can work only in the presence of HCl .Now the food moves
into small intestine by the sphincter muscles.
3.The small intestine recieves the secretions of the liver and pancreas
for digesting food.The food coming from the stomach is acidic and
has to be made alkaline for pancreatic enzymes to act.Bile juice
 from the liver acts on the fats.The Bile salt acts upon the fat globules
and helps enzymec to act upon them.Pancreatic enzymes like trypsin
act upon protiens and lypase on the fats.The protiens are converted
into amino acid, carbohydrates into glucose and fats into fatty acids
and glycerol.
4.The inner lining of the small intestine has villi which
increase the surface area of absorption.The blood vessels in it take
 up the absorbed  food and distributed in the body.
5.The unabsorbes food reaches the large intestine where more villi
absorb water and rest of the material is removed from the body via the
anus.

Chemistry questions for class X

1. Write the balanced chemical equation for the following reaction and identify the type of reaction and define it.  ‘Iron III oxide reacts with Aluminium and gives molten iron and aluminium oxide’.
2. Name the following :

     (a) A metal which is preserved in kerosene

      (b) A lustrous coloured non metal

      (c) A metal which can melt while kept on palm.

      (d) A metal, which is a poor conductor of heat.

      3.   A reddish brown coloured metal, used in electrical wires, when powdered and heated strongly in an open china dish, its colour turns black.  When hydrogen gas is passed over this black substance, it regains its original colour.  Based on the above information answer the following questions.

(i) Name the metal and the black coloured substance formed.

(ii) Write balanced chemical equations for both the reactions.

      4.   (a) Give an example for a combination reaction which is exothermic.  

            (b) Name the phenomenon due to which the taste and smell of oily food changes    when kept for a long time in open.  Suggest one method to prevent it. 

      5.   (a) Write the name given to bases that are highly soluble in water ?  Give an example.

            (b) How is tooth decay related to pH ?  How can it be prevented ? 

 (c) Why does bee sting cause pain and irritation ?  Rubbing of baking soda on the  sting area gives relief.  How ? 

      6.   (a) Why is calcium starts floating when added to water ? 

            (b) Most of the metals do not give hydrogen while reacting with nitric acid.Why ? 

 (c) Write equation for the reaction of iron with steam.  Name the compound of  iron obtained.

      7.   Identify the type of chemical reaction  and also write the chemical equation for the reaction that takes place when a solution of potassium chloride is mixed with silver nitrate solution.  Write the chemical name of one of the products obtained.

      8.   What is rancidity? Mention any two ways by which rancidity can be prevented ?

      9.   Differentiate between strong and weak acids.  Identify the strong and weak acids from the following list of acids. Hydrochloric acid, acetic acid, formic acid, nitric acid.

     10.  Write two observations that you will make when an iron nail is kept in an aqueous solution of copper sulphate ? Write the chemical equation for this reaction.

     11.  A current carrying conductor produces a magnetic field around it. Is there a similar magnetic field produced around a thin beam of moving

            (i) electrons

            (ii) neutrons.  Justify your answer.

     12.  Write balanced chemical equation for the reactions that take place during respiration. Identify the type of combination reaction that takes place  during this process and justify the name. Give one more example of this type of reaction.

     13.  A compound which is prepared from gypsum, has the property of hardening when mixed with right quantity of water.

           (i) Identify the compound and write its chemical formula.

           (ii) Write the chemical equation for its preparation.

             (iii) List any two uses of the above compound.

      14.  Give reasons for the following :

             (i) Ionic compounds have high melting point and boiling point.

             (ii) Ionic compounds conduct electricity in molten state.

             (iii) Ionic compounds are solids at room temperature and are somewhat hard.

15. How is the method of extraction of metals high up in the reactivity series different from that for metals in the middle ? Why the same process cannot be applied for them ?Explain giving equations, the extraction of sodium.

physics important questions for class 10

Ques-1   How much current will an electric bulb draw from 220 V source if the resistance of the bulb is 1200 ohm  ?  If in place of bulb, a heater of resistance 100  is connected to the sources calculate the current drawn by it?
Ans-1   According to ohm's law we know that I=VR:  I=220*1200= 264000 ampere.
           (2)If heater is placed instead of bulb then current will be: I=VR,I=220*100=22000 ampere.
Ques-2   Define electric power. 
(b) An electric bulb is connected to a 200 V generator.  The current is 0.5 A.  What is the power of the bulb ?
Ans-2  (a) ELECTRIC POWER--- Electric power is defind as the amount of electric energy consumed in a circuit per unit time.
             (b)we know P=V/I=200/0.5=400 watt.
Ques-3   A resistance wire is stretched to double its length . How will its resistance change ?
Ans-3   we know,  R=pl/a     (1)
When wire is pulled, its lenth increases and area of cross-section decreases i.e,wire becomes thin but volume of wire remains the same.
new lenth,   l'=2l
new area,    A=A'
since original volume of wire=new volume
                  Al=A'l' orAl=A'*2l
                     or A'=A/2
     New resistance,  R'=pl'/A'=p82l/A/2=4pl/A   (2) Dividing (1) and (2). we get   R'=4R
Thus the new resistance of wire = 4 times its original resistance.
Ques-4   Explain the function of fuse in a domestic electric circuit ? An electric oven having power rating 2000 W, 220V is used in an electric circuit, having a fuse of 5A rating. What is likely to happen when the oven is switched on ? Explain.
Ans-4   Fuse is a safety devicee connected in series with the electric circuit.Electric fuse is a wire made of a material whose melting point is very low. For example-of the material of making fuse wire are copper or tin-lead alloy.
             A current flows in the circuit and hence through the fuse wire, a large amount of heat is producced due to this large amount of heat, the fuse wire melts and the circuit will break so that current stops flowing in the circuit. this saves the electric circuit from burning. 
                   
Ques-5    An electric heater rated 800 W operates 6 h/day. Find the cost of energy to operate it for 30 days at ` 3.00 per unit.
Ans-5     Energy consumed by electric heater in one day: 800w*6h=4800wh=4.8kwh
      Energy consumed in 30 days=4.8*30=144units
   cost of one unt = rs3.00
    cost of 144units=144*Rs3.00=432
So electricity bill of 30 days is Rs 432
Ques-6  Why element of electrical heating devices are made up of alloys?
Ans-6 They are made up of alloys because alloys have more melting point .since wires are made up of nichrome which is the alloy of metal.the resistivity of nichrome is more than the resistivities of metal used to make it. hence nichrome does not burneven at high temperature.the melting point of nichrome is 1500`c.That is why heating elements are made up of an alloy that is an alloy.





 

           PHYSICS  UNIT TEST SOLUTION

Q1-Prove the equivalent resistance in series?

here,the current flowing throughout is same but voltage is different at every resistance

            total voltage= T.V

     Voltage on R1=  V1

     Voltage on R2=V2

     Voltage on R3=V3

Since we know that here 

T.V=V1+V2+V3      _1

Also V=IR

So.we can write 1 as

t(IR)= 1(IR)+2(IR)+3(IR)                               {here t means total}

t(IR)=I(R1+R2+R3)

t(IR)/I= R1+R2+R3                   {I cancels with I}

So,T.R=R1+R2+R3

           hence proved

Q2-Define resistance of the conductor
ANS-Resistance of a conductor is the obstraction in the path of the current.

Q3-What is the mathematical representation of Ohm's law?

ANS- Mathematically,the representation of Ohm's law is V=IR

Q4-What is the effect on the resistance when the length and the area of the ire is changed?

ans- Since we know that

         R= ρ(L/A)             {here L=length and A =area]

so,R∝L AND R 1/∝ A

So if length is changed then resistance changes likewise.  If 

area is decreased then resistance increases and if area is increased then  resistance increases

  

UNIT TEST SOLUTIONS(BIOLOGY)

Q-1-How Does Oxygen And Carbon-Dioxide Enters In Our Body?

Ans-1-Oxygen And Carbon-Dioxide Enters In Our Body By Blood. Oxygen Is Carried By Red Blood Cells.Many Other Substanses Like Salt Are Also Transported By Blood.

Q-2- Differentiate Between Arteries And Viens.

Ans-2- Arteries -Arteries Carry Blood Away From The Heart

Arteries Have Thick Walls

Arteries do not Have Valves

Veins- Veins Carry Blood Towards The Heart.

Veins Have Thin Walls

Veins Have Valves.

WHY IS THIS SO

• Why do objects look different colours ?

The white light around us is made up of a mixture of different colours of light. The surfaces of objects absorb some colours and reflect others back. Our eye can see only those colours that are reflected. An object that reflects all the colours of light appears white and vice versa to this appears black. A tomato absorbs all the colours except red, which it reflects back to us. so that is how we are able to see tomato's red colour.

• Why do we need gravity?

Gravity is what keeps us and everything else, on earth. It is the tendency of objects with mass to be attracted to each other. an objects mass is the amount of material it contains. the bigger the mass of the object, the stronger will be it's gravity.

• Why can't we ever take a break from breathing?

Breathing takes air in and out of our lungs, and that air contains the gas oxygen. Every one of our trillion of body cells need a constant supply of oxygen, 24 hrs a day, and oxygen is something that our body cannot store- no break! Breathing also removes carbon dioxide from our body.

Study: Playing Tetris Can Help People Beat Lazy Eye

Researchers found that adults who suffered from amblyopia–lazy eye–could train their eyes to work together by playing Tetris. Now, the researchers want to test this unconventional therapy in kids.
Around 1 in 50 kids has amblyopia, and the common treatment is to cover the strong eye with a patch to strengthen the weaker eye. If you have kids, you know that getting a child to wear an eye patch might not be the easiest or most pleasant thing to do. And for adults, the patching technique is not very effective. The Tetris technique doesn’t focus on one eye or the other, but rather trains the eyes to work together and helps the whole visual system learn how to see properly anew.

Source: http://www.positscience.com/  

 

WHAT IS A LIGHTNING ARRESTER??

A lighting arrester is a piece of equipment that is designed to protect electrical systems and components from damages that can be caused by surges of electricity. Such surges can be the result of lightning or electrical switching and can be very dangerous, especially for electronics like computers. Utilities fit their power lines with lightning arresters, as well as other safety measures and these devices can also be mounted on individual electrical boxes.

When a surge of electricity hits an electrical system, it attempts to equalize and dissipate itself, taking the most efficient routes. A lightning arrester provides a path of least resistance for doing this, routing the excess electricity away from the system and into the ground where it can dissipate without doing any harm. The lighting resistor includes components attached to the electrical system with leads that reach the ground.

Soft, clay soils tend to be ideal for grounding, although other soil types can be used in a pinch. The resistance of the soil should be measured before a lightning arrester is installed to find an area with resistance that is as low as possible. This will allow the electricity to quickly flow out through the lightning arrester before it has a chance to enter the system and damage either the system or its components.

                                              SOURCE- WWW.WISEGEEK.COM

WHY DO LIZARDS LOSE THEIR TAILS??

Have you ever seen a gecko without a tail and wondered why they do that? Lizards and other amphibians have the ability to regenerate their tails, which means that they will grow a new one.

Lizards can lose their tails at-will and are able to grow new ones through limb regeneration. But why do geckos lose their tails?  We will explore the reasons behind this method of self-defense.

Why Do Lizards' Tails Fall Off?

Much like octopi and starfish, lizards have evolved over time in order to use their limb regeneration for self-defense. When attacked by a predator, lizards sometimes detach their tail to distract a predator. After the tail falls off, it will continue to wiggle. If the lizard is lucky, the predator will not be able to differentiate between the lizard and its wiggling tail.

Since the lizard quickly scurries away, the predator is more likely going to move their attention toward the tail, which is staying in one place, yet appears to be alive.

Lizards have evolved to be able to detach their tails at-will, yet, they sometimes do not fully separate. Sometimes, the lizards are not so lucky, and they must live with a partially detached tail while the cells around it begin to regenerate.

BLOOD PRESSURE

CANDLES MAKE ELECRICITY

RESISTORS IN SERIES AND PARALLEL

RESPIRATION IN FISHES

RESPIRATORY ORGANS IN AMPHIBIANS

CLASS X MCQ BASED

q1. The kidneys in human beings are a part of system for
a.nutrition
b.respiration
c.excretion
d. transpiration
q2.The xylem in plants are responsible for
a.transport of water
b.transport of food
c.transport of amino acid
d.transport of oxygen
q3.The autotrophic mode of nutrition requires
a.co2 and h2o
b.chlorophyll
c.sunlight
d.all of the above
q4.The breakdown of pyruvate to give co2,h2o and energy takes place in
a.cytoplasm
b.mitochondria
c.chloroplast
d.nucleus
q5.Where is bile produced?
a. gall blader
b.blood
c.liver
d.spleem

ANSWERS-1-C 2-A 3-D 4-B 5-C

Ohm's law for class 10

 

 

WORKING OF HEART

to learn to balance chemical equations

Photosynthesis in plants

HUMAN DIGESTIVE SYSTEM

HUMAN RESPIRATORY SYSTEM

 

SOURCE-http://www.youtube.com/watch?v=TU4WBbwOWU4