We obtain a precipitate only when barium chloride solution is added to sodium sulphate solution Barium chloride + Sodium sulphate ⟶ Barium sulphate (ppt.) + Sodium chloride
We obtain a precipitate only when barium chloride solution is added to sodium
sulphate solution
Barium chloride + Sodium sulphate ⟶ Barium sulphate (ppt.) + Sodium chloride
Liquid in C is most acidic, followed by that in A and B. Greater the acidic strength, smaller is the pH value. Hence pH value of liquid in B is more than that in A and C.
Liquid in C is most acidic, followed by that in A and B. Greater the acidic strength, smaller is the pH value. Hence pH value of liquid in B is more than that in A and C.
Electrical resistance of a conductor is a measure of the opposition offered by it for flow of electric charge through it. Mathematically, resistance is given as: Resistance R = Potential difference across the conductor V/Current I SI unit of resistance is ohm Ω. Resistance of a conductor is said toRead more
Electrical resistance of a conductor is a measure of the opposition offered by it for flow of electric charge through it. Mathematically, resistance is given as:
Resistance R = Potential difference across the conductor V/Current I
SI unit of resistance is ohm Ω. Resistance of a conductor is said to be 1 Ω, if a potential difference of 1 volt is to be applied across its ends to maintain a flow of 1 ampere of current. The resistance R of a conductor is (a) directly proportional to its length L, (b) inversely proportional to its cross-section area A, and (c) depends on the nature of the material of the conductor. Thus,
R ∝ L/a or R = pl = pL/A,
where p is a constant depending upon the nature of the material of conductor and is known as its resistivity.
(i) The resistance of a wire is doubled if its length is double keeping other factors unchanged. It is because R ∝ L.
(ii) If radius of wire is doubled then its cross-section area (A =πr²) becomes 4 times of its original value. Since R ∝ 1/A hence the new resistance of wire becomes 1/4 th, of its original value.
(a) Three common features of respiratory organs of animals : (i) Animals absorbs oxygen from water or air hence have a structure that increases the surface area which is in contact with the oxygen rich atmosphere. (ii) Since exchange of oxygen-carbon dioxide has to take place across this surface, itRead more
(a) Three common features of respiratory organs of animals :
(i) Animals absorbs oxygen from water or air hence have a structure that increases the surface area which is in contact with the oxygen rich atmosphere.
(ii) Since exchange of oxygen-carbon dioxide has to take place across this surface, it is very fine and delicate.
(iii) ln order to protect this surface, it is placed within the body, so there are passages that take air to this area.
(b) Differences between aerobic and anaerobic respiration:
Aerobic respiration:-
(i) Oxygen is used to breakdown glucose.
(ii) Glucose is broken down completely to release large amount of energy.
Anaerobic respiration:-
(i) Do not involve oxygen to breakdown glucose.
(ii) Breakdown of glucose is incomplete to release small amount of energy.
In the experiment to show that ‘light is necessary for photosynthesis’, the reason for boiling the leaf in alcohol is to:
Alcohol being organic solvent breaks membranes and dissolves chlorophyll so that blue-black colour of starch-iodine complex is clearly noticeable.
Alcohol being organic solvent breaks membranes and dissolves chlorophyll so that
See lessblue-black colour of starch-iodine complex is clearly noticeable.
We will observe a precipitation to occur when:
We obtain a precipitate only when barium chloride solution is added to sodium sulphate solution Barium chloride + Sodium sulphate ⟶ Barium sulphate (ppt.) + Sodium chloride
We obtain a precipitate only when barium chloride solution is added to sodium
See lesssulphate solution
Barium chloride + Sodium sulphate ⟶ Barium sulphate (ppt.) + Sodium chloride
A student took 5 mL of lemon Juice in each of test tubes A, B and C. She added 5 mL of water in A and 20 mL of water in B. She tested for pH value in all the three tubes. She would find that pH value of liquid :
Liquid in C is most acidic, followed by that in A and B. Greater the acidic strength, smaller is the pH value. Hence pH value of liquid in B is more than that in A and C.
Liquid in C is most acidic, followed by that in A and B. Greater the acidic strength, smaller is the pH value. Hence pH value of liquid in B is more than that in A and C.
See lessWhat is meant by resistance of a conductor? Name and define its SI unit. List the factors on which the resistance of a conductor depends. How is the resistance of a wire affected if: (i) its length is doubled, (ii) its radius is doubled?
Electrical resistance of a conductor is a measure of the opposition offered by it for flow of electric charge through it. Mathematically, resistance is given as: Resistance R = Potential difference across the conductor V/Current I SI unit of resistance is ohm Ω. Resistance of a conductor is said toRead more
Electrical resistance of a conductor is a measure of the opposition offered by it for flow of electric charge through it. Mathematically, resistance is given as:
Resistance R = Potential difference across the conductor V/Current I
SI unit of resistance is ohm Ω. Resistance of a conductor is said to be 1 Ω, if a potential difference of 1 volt is to be applied across its ends to maintain a flow of 1 ampere of current. The resistance R of a conductor is (a) directly proportional to its length L, (b) inversely proportional to its cross-section area A, and (c) depends on the nature of the material of the conductor. Thus,
R ∝ L/a or R = pl = pL/A,
See lesswhere p is a constant depending upon the nature of the material of conductor and is known as its resistivity.
(i) The resistance of a wire is doubled if its length is double keeping other factors unchanged. It is because R ∝ L.
(ii) If radius of wire is doubled then its cross-section area (A =πr²) becomes 4 times of its original value. Since R ∝ 1/A hence the new resistance of wire becomes 1/4 th, of its original value.
(a) State three common features of respiratory organs of animals. (b) Write two points of difference between aerobic respiration and anaerobic respiration.
(a) Three common features of respiratory organs of animals : (i) Animals absorbs oxygen from water or air hence have a structure that increases the surface area which is in contact with the oxygen rich atmosphere. (ii) Since exchange of oxygen-carbon dioxide has to take place across this surface, itRead more
(a) Three common features of respiratory organs of animals :
See less(i) Animals absorbs oxygen from water or air hence have a structure that increases the surface area which is in contact with the oxygen rich atmosphere.
(ii) Since exchange of oxygen-carbon dioxide has to take place across this surface, it is very fine and delicate.
(iii) ln order to protect this surface, it is placed within the body, so there are passages that take air to this area.
(b) Differences between aerobic and anaerobic respiration:
Aerobic respiration:-
(i) Oxygen is used to breakdown glucose.
(ii) Glucose is broken down completely to release large amount of energy.
Anaerobic respiration:-
(i) Do not involve oxygen to breakdown glucose.
(ii) Breakdown of glucose is incomplete to release small amount of energy.