Q 1 – When pH strip is dipped in each bottle, the color shown by bottle A and B will be respectively.
(a) orange, blue
(b) blue, orange
(c) green, blue
(d) blue, green
(a) orange, blue
Q 2 – In an attempt to demonstrate electrical conductivity through an electrolyte, the following apparatus (figure) was set up.
Which among the following statement (s) is (are) correct?
1. Bulb will not glow because electrolyte is not acidic.
2. Bulb will glow because NaOH is a strong base and furnishes ions for conduction.
3. Bulb will not glow because circuit is incomplete.
4. Bulb will not glow because it depends upon the type of electrolytic solution.
(a) 1 and 3
(b) 2 and 4
(c) Only 2
(d) Only 4
(c) Only 2
Q 3 – An element X has electronic configuration 2, 8, 1 and another element Y has electronic configuration 2, 8, 7. They form a compound Z. The property that is not exhibited by Z is
(a) It has high melting point.
(b) It is a good conductor of electricity in its pure solid state.
(c) it breaks into pieces when between with hammer.
(d) it is soluble in water
(b) It is a good conductor of electricity in its pure solid state.
Q 4 – When hydrogen sulfide gas is passed through a blue solution of copper sulfate, a black precipitate of copper sulfide is obtained and the sulfuric acid so formed remains in the solution. The reaction is an example of:
(a) Combination reaction
(b) displacement reaction
(c) decomposition reaction
(d) double displacement reaction
(d) double displacement reaction
Q 5 – An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be
(a) calcium
(b) carbon
(c) silicon
(d) iron
(a) calcium
Q 6 – Two pink colored flowers on crossing resulted in 1 red, 2 pink and 1 white flower progeny. The nature of the cross will be
(a) double fertilization
(b) self pollination
(c) cross fertilization
(d) no fertilization
(b) self pollination
Q 7 – A student require hard water for an experiment in his laboratory which is not available in the neighboring area. In the laboratory there are some salts, which when dissolved in distilled water can convert it into hard water. Select from the following groups of salts, a group, and each salt of which when dissolved in distilled water will make it hard.
(a) Sodium chloride, Potassium chloride
(b) Sodium sulfate, Potassium sulfate
(c) Sodium sulfate, calcium Sodium sulfate
(d) Calcium sulfate calcium chloride
(d) Calcium sulfate calcium chloride
Q 8 – At the time of short circuit, the electric current in the circuit :
(a) vary continuously
(b) does not change
(c) reduces substantially
(d) increases heavily
(d) increases heavily
Q 9 – Identify the substances that is oxidized and the substances that is reduced in the following reactions:
(a) H2, CuO
(b) H2, H2O
(c) H2, Cu
(d) Cu, H2
(d) Cu, H2
Q 10 – Which of the following are correctly matched in the given table?
1. | Dissolution | Solute gets dissolved in a solvent. |
2. | Exothermic | Heat in absorbed. |
3. | Reversible change | Reactants can be obtained. |
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3
(b) 2 and 3
Q 11 – Each gamete carries only one allele. This is proposed in which law?
(a) Law of dominance
(b) Law of segregation
(c) Law of genetics
(d) Law of assortment
(b) Law of segregation
Q 12 – In the given activity, the lime water of which test tube will get milky faster?
(a) Test tube (a)
(b)Test tube (b)
(c) Both test tube will take same time
(d) Can’t say
(c) Both test tube will take same time
Q 13 – The resistivity does not change if
(a) The material is changed
(b) The temperature is changed
(c) The shape of the resistor is changed
(d) both material and temperature are changed
(c) The shape of the resistor is changed
Q 14 – From the mouth the food is taken to the stomach through ………. .
(a) Bile duct
(b) Pancreas
(c) Diaphragm
(d) esophagus
(d) esophagus
Q 15 – Which of the following statements is not correct?
(a) All metal carbonates react with acid to give a salt, water and carbon dioxide.
(b) All metal oxides react with water to give salt and acid.
(c) Some metals react with acids to give salt and hydrogen.
(d) Some non – metal oxides react with water to from acid.
(b) All metal oxides react with water to give salt and acid.
Q 16 – The correct structural formula of butanoic acid is
Q 17 – Assertion : All the plants possess autotrophic mode of nutrition.
Reason : Due to the presence of green colored pigment chlorophyll in them.
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
(c) Assertion is true but Reason is false.
(d) Both Assertion and Reason are false.
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
Q 18 – Assertion : Ethanol is obtained during the anaerobic process of respiration.
Reason : This is due to presence of oxygen and it takes place in the mitochondria.
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
(c) Assertion is true but Reason is false.
(d) Both Assertion and Reason are false.
(c) Assertion is true but Reason is false.
Q 19 – Assertion : The genetic complement of an organism is called genotype.
Reason : Genotype is the type of hereditary properties of an organism.
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
Q 20 – Assertion: A direction current flows through a metallic rod, produced magnetic field only outside the rod.
Reason: There is no flow of charge carriers inside the rod.
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
Q 21 – Which are the first simple molecules of food produced during photosynthesis? What happens to these simple molecules in the leaves later?
(i) Glucose molecules are the first simple molecules of food produced darning photosynthesis.
(ii) These molecules combine to produce starch Which is stored in various arts of the plant.
Q 22 – Draw a neat diagram to show the refraction of a light ray through a glass prism and label on it the angle of incidence and angle of deviation.
Or
What is the scattering of light ? Explain with the help of an example.
or
The phenomenon of change in the direction of propagation of light caused by a large of present in the atmosphere is called scattering of light .
Example. The path of beam of light becomes visible through a colloidal solution due to scattering of light.
Q 23 – What is the cause of peptic ulcer ?
Peptic ulcer is caused by imbalance in the rate of gastric juice secretion. High acidic secretion causes irritation of the stomach. This results in poor secretion of mucus that protects the inner lining. Ultimately, the mucosal layer is eroded causing the ulcer.
Q 24 – What do you mean by diffusion ?
The Movement of molecules from their Higher concentration to lower concentration is called diffusion.
Q 25 – Stomata of desert plants remain closed during day time. How do they take up carbon dioxide and perform photosynthesis?
In desert plants the stomata open at night.
They take in carbon dioxide at night, and is stored in the form of an intermediate which is used during day for photosynthesis (When the stomata are closed).
Also, chlorophyll of the plant are located in the stem as levesare reduced to spines and stem takes the function of photosynthesis.
Such plants undergo CAM photosynthesis as they open up their stomata during night and take in CO2.Stomata remains close during the day time to prevent the loss of water by transpiration. They store the CO2 in their cells until the sun comes out and they can carry on with photosynthesis during the day time.
Q 26 – “Energy flow in a food chain is unidirectional.” Justify this statement.
Producers convert solar energy into chemical energy in the form of organic compounds. The primary consumers derive nutrients from the producers. Therefore, energy passes to the next trophic level from the producers. The process continues from one trophic level to another. The energy that is captured by the autotrophes passes to the consumers and decomposers and it never goes back. So flow of energy is unidirectional as it goes in one direction.
Q 27 – Explain the following statements :
(a) Most metal oxides are insoluble in water but some of these dissolve in water. What are these oxides and their solutions in water called ?
(b) At ordinary temperature the surface of metals such as magnesium, aluminium, zinc etc., is covered with a thin layer. What is the composition of this layer ? State its importance.
(c) Some alkali metals can be cut with a knife.
(a) Solution of metal oxides in water is called alkali (soluble base), e.g. sodium hydrogen (NaOH), Potassium hydrogen (KOH).
(b) This layer is oxide layer. It makes the metal less reactive (Passive) and Makes it more useful because it cannot get corroded and remains as it is.
(c) It is because these metals are very soft, e.g sodium metals can be cut with knife.
Q 28 – What would be the reading of ammeter and voltmeter in the given circuit?
Or
Two resistors with resistances 10 Ω and 15 Ω are to be connected to emf 12 V so as to obtain :
(i) minimum current
(ii) maximum current. How will you connect the resistance in each case ? Calculate the strength of the total current in the circuit in the two cases.
Drop across ∣Ω resister 1 × 1 = 1v
Reading on voltmeter
= 1 × 2 = 2v
Or
To obtain minimum current, the two resistors should be connected in series so that the equivalent resistance,
To obtain maximum current, the two resistors should be connected in parallel so that the equivalent resistance,
Q 29 – An object 4 cm in height is placed at 15 cm in front of a concave mirror of focal length 10 cm. At what distance from the mirror should a screen be placed to obtain a sharp image of the object. Calculate the height of the image.
Q 30 – It is said that, there is a need to put a complete ban on the products containing aerosols. What are aerosols? Why is there a demand to put a ban on them?
An aerosol is defined as a colloidal system of solid or liquid particles in a gas. An aerosol includes both the particles and the suspending gas, which is usually air. Aerosols need to be banned because CFC’s (Chlorofluorocarbons) are used in them as propelling agents that keep the pressure in the can constant. CFCs are air pollutants that can have several adverse effects. So, a ban on aerosols is in demand.
Q 31 – A shining metal M , of burning gives a dazzling white flame and changes to a white powder N .
(a) Identify M and N .
(b) Represent the above reaction in the form of a balanced chemical equation.
(c) Does M undergo oxidation or reduction in this reaction ? Justify.
(i) M is Magnesium (Mg) and N is Magnesium Oxide (MgO).
(ii) The above reaction can be represented in the form of a balanced chemical equation as follows :
2Mg + O2 —-> 2MgO
(iii) In this reaction, Mg undergoes oxidation as the reaction is combustion and in this Mg is combining with oxygen.
Q 32 – Explain the significance of peristaltic movement that occurs all along the gut during digestion.
The role of peristalsis in the digestive system is that it is the way food is propelled down the esophagus and into the stomach; then peristalsis moves the digested food through the small and large intestine and then through the rectum and anus. It is a series of smooth muscle contractions and relaxations moving food in a wave-like manner through the different processes in the gastrointestinal tract.
Q 33 – Name the type of chemical reaction represented by the following equations :
(i) Decomposition reaction/endothermic
(ii) Combination reaction/endothermic.
(iii) Displacement reaction.
Q 34 – Classify the following ecosystems into natural and artificial ecosystem:
Forest ecosystem, aquarium, Marine ecosystem and crop land ecosystem.
Natural ecosystem : forest ecosystem and marine ecosystem.
Artificial ecosystem : Aquarium and cropland ecosystem.
Q 35 – How are the breathing movements controlled?
The breathing movements are largely controlled by a respiratory center located in the medulla oblongata of the brain . This center is stimulated by the carbon dioxide contontsof the blood.
Q 36 – No rainbow could be observed from the surface of the moon by the astronauts. Give reason.
The moon does not have any blanket of air or atmosphere and consequently , in the absence of water droplets , no dispersion of sun rays is possible. Therefore rainbow could not be observed from the surface of the moon by the astronauts.
Q 37 – (a) Define power of a lens and write its S.I. unit.
(b) A convex lens of power 4 D is placed at a distance of 40 cm from a wall. At what distance from the lens should a candle be placed so that its image is formed on the wall ?
(a) power of a lens is the reciprocal of local length expressed in meters.
S.I. unit of power is dioptre.
(b) As we know that,
Q 38 – (a) A divergent lens has focal length of 20 cm. At what distance should the object from the lens be placed so that an image is formed 10 cm away from the lens? What is the magnification produced, by the lens?
(b) Draw a ray diagram to show the position and nature or the image formed by a convex lens when an object is placed between optical centre and focus of the lens
Q 39 – Lenses are objects made of transparent materials such as glass or clear plastic that has curved surfaces. Diverging lenses are thicker at their edges than at their centers and makes light rays passing through them spread out. Converging lenses are thicker in their middle than at this edges and make light rays passing through them focus at a point. These are used in spectacles to help people with poor vision see better. The converging lenses magnify by bending the rays of light that pass through them to meet at a point called focus. Thicker the converging lens is at its centre, the more its magnifies and closer the focus is to the lens.
(i) Ravi uses two lenses A and B of same size and same material as shown. P1 and P2 are the powers of A and B. An object is kept at the same distance from the lens between F and 2F of each lens on the principal axis in turn. Let I1 and I2 be the image formed by two lenses respectively. What is the relation of image distances of both lenses?
(ii) Write down the relation between the powers of lens of both lenses?
(iii) Meenakshi uses above two lenses A and B along with another two lenses C and D, as shown :
She is able to see the subject matter on the black board while sitting in the front row in the classroom but is unable to see the same matter while sitting in the last row.
Which of the above four lenses will she require to correct the defect in her vision? Why ?
Or
(iv) Natasha places an object on the principal axis of above given lens A. One end of this object coincides with the focus F and the other end with 2F. What will be the nature of the image formed by the lens on the other side ?
.(i) Distance of image I2 will be less than distance of I1 from the lens.
(ii) P1 P2
(iii) She will require lens C. Because, she is suffering from myopia convene lens is required to correct.
Or
(iv) The natural of image formed will be infinite in size.