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MARCH 2022

SCIENCE AND TECHNOLOGY PAPER-I

(REVISED COURSE)

Q. 1. (A) Write the correct alternative :

(i) Gold plated ornaments is the example of……………………..
(A) Electroplating
(B) Alloying
(C) Anodizing
(D) Galvanizing

(ii) The functioning of the satellite launch vehicle is based on…………………

(A) Newton’s first law of motion

(B) Newton’s second law of motion

(C) Newton’s third law of motion

(D) Newton’s universal law of gravitation

(iii) ……………………… is one of the combustible component of L.P.G.
(A) Ethane
(B) Propane
(C) Methane
(D) Ethene

(iv) The power of a convex lens of focal length is……………………
(A)
(B)
(C)
(D)

(v) …………… colour is deviated the least in the spectrum of white light obtained with a glass prism.
(A) Red
(B) Yellow
(C) Violet
(D) Blue

(B) Answer the following :

(i) Find the odd one out :

INSAT, GSAT, IRS, PSLV

(ii) Complete the correlation :

Group 1 : Alkali metals : : ‘……………….. : Halogens.

(iii) Match the correct pair :

Column ‘ ‘ Column ‘B’

Refractive index of water (a) 1.31

(b) 1.36

(c) 1.33

(iv) State True or False :

An electric motor converts mechanical energy into electrical energy.

(v) Write the IUPAC name for the following structural formula :

Ans.

(A) 1. (i) (A) Electroplating (ii) (C) Newton’s third law of motion

(iii) (C) Methane (iv)(A) (v) (A) Red

(ii) Complete the following table

Answer:

4. (i) (a) In the figure, Myopia or Nearsightedness defect of vision is represented.

(b) The reasons for this defect:

1. The curvature of the cornea and the eyelens increases. The muscles near the lens cannot relax so that the converging power of the lens remains large.
2. The eyeball elongates so that the distance between the lens and the retina increases.

(c) This defect can be corrected using spectacles with concave lens. This lens diverges the incident rays and these diverged rays can be converged by the lens in the eye to form image on the retina.

(d)

(ii)

(B) (i) IRS

(ii) Group 17

(iii) (c) 1.33

(iv) False

(v) The IUPAC name of the compound is propan-2-ol.

Q. 2. (A) Give scientific reasons (any two) :

(i) Atomic radius goes on increasing down a group.

(ii) Simple microscope is used for watch repairs.

(iii) It is recommended to use airtight container for storing oil for long time.

(B) Answer the following questions (any three) :

(i) An object takes to reach the ground from a height of on a planet. What is the value of ‘ ‘ on the planet?

(ii) Draw a neat labelled diagram of Hope’s Apparatus.

(iii) State the Laws of Refraction.

(iv) Answer the following :

(a) Name the main ore of aluminium.

(b) What impurities are present in aluminium ore?

(v) Observe the given figure of Fleming’s Left Hand Rule and write the labels of ‘ ‘ and ‘B’ :

Ans. (A) (i) Atomic radius goes on increasing down a group because, down a group, the atomic number increases as a result nuclear charge increases. Thus the outer electrons are added to the atoms at every step. As the number of shells in the atoms increases gradually due to which the size of the atoms also increases.

(ii) Because simple microscope has a convex lens, which has the ability to produce a magnification of about 20 times. The convex lens, of small focal length is used in a simple microscope.

So, it is used by the watch repairers to see the minute parts of the watch clearly without causing any strain to the eyes.

(iii) It is recommended to use airtight container for storing oil for long time because if edible oil is allowed to stand for a long time, it undergoes air oxidaiton, it becomes rancid and its smell and taste change.

(B) (i) Given, time , height

To improve :

Formula Used :

Solution : But the values in the formulae,

(ii)

(iii) 1. The incident ray the refracted ray and normal to the interface of two media at the point of incidence all lie in the same plane.

1. For given pair of media, the ratio of sine of the angle of incidence to the sine of the angle of refraction is constant.

(a) The second law is also called as Snell’s law.

(b) If ‘ ‘ is the angle of incidence and ‘ ‘ is angle of refraction, then,

(c) This is called refractive index of second medium with respect to first medium, it is denoted by .

(iv) (a) The main ore of aluminium is bauxite .

(b) Salt, 0.5 to water and other oxidies are present in aluminium ore as the impurities.

(v)

Q. 3. Answer the following (any five) :

(i) Write the demerits of Mendeleev’s periodic table.

(ii) State the laws related to the given diagram :

(iii) Identify the type of chemical reaction given below :

(a)

(b)

(c)

(iv) If the speed of light in a medium is , what is the absolute refractive index of the medium?

(Speed of light in vacuum ).

(v) Read the following paragraph and answer the questions based on it. If heat is exchanged between a hot and cold object, the temperature of the cold object goes on increasing due to gain of energy and the temperature of the hot object goes on decreasing due to loss of energy.

The change in temperature continues till the temperatures of both the objects attain the same value. In this process, the cold object gains heat energy and the hot object loses heat energy. If the system of both the objects is isolated from the environment by keeping it inside a heat resistant box, then no energy can flow from inside the box or come into the box.

(a) Heat is transferred from where to where?

(b) Which principle do we learn about from this process?

(c) How will you state the principle briefly?

(vi) Complete the following table for convex lens :

(vii) Explain the following terms :

(a) Metallurgy

(b) Ores

(c) Gangue

(viii) State the importance of Space Mission.

Ans. (i) Demerits of Mendeleev Period Table are :

1. He was unable to locate the exact position of the hydrogen in the periodic table.
2. Increase in atomic mass was not regular while moving from one element to another. Hence, the number of elements yet to be discovered was not predictable.
3. Later on, isotopes of elements were found which violated Mendeleev’s periodic law.
4. At certain places, an element of higher atomic mass has been placed before an element of lower mass. Eg. Cobalt is placed before nickel .

(ii) (1) Kepler’s First Law : The orbit of planets are elliptical with sun at one of the foci.

(2) Kepler’s Second Law : The radius vector from the sun to the planet sweeps equal areas in equal intervals of time.

(3) Kepler’s Third Law : Square of the time period of revolution of a planet around the sun is directly proportional to the cube of mean distance of the planet from the sun.

(iii) (a) Displacement reaction.

(b) Reduction reaction.

(c) Endothermic reaction.

(iv) Given, Speed of light in medium ,

Velocity of light in vacuum

Formula used :

Solution :

Hence, the absolute refractive index of the medium is 2 .

(v) (a) Heat is transferred from hot body to cold body i.e., from higher temperature to lower temperature.

(b) We learn the principle of heat exchange from this process.

(c) The heat energy lost by hot object is always equal to heat gained by cold object provided that the system of both the object is isolated.

(vi)

(vii) (a) Metallurgy : The extraction of metals from their ores and then refining them for use is known as metallurgy.

(b) Ores : The minerals from which metals can be profitably extracted are called ores.

(c) Gangue : The unwanted impurities of sand, soil, rocky substances etc. present in the ore are called gangue.

(viii) (1) Due to space missions, the world has come closer. It has become very easy to contact a person in any part of the world within seconds.

(2) Due to internet, every information is available at our fingertips. We can gather information about world wide events sitting at home.

(3) The use of satellites can give us advance alerts about various natural calamities.

Q.4. Answer any one of the following:

(i) Observe the following diagram and answer the questions given below :

(a) Identify the above diagram.

(b) Write the principle on which the above appliance works.

(c) Write the working of the above appliance.

(d) Write the use of the above appliance.

(ii) (a) Identify saturated and unsaturated hydrocarbon from the given structural formula :

(b) Draw electron dot structure for (1) and (2).

(c) Define Homologous series.

Ans.

(i) (a) It is an working electric generator.

(b) AC generator works on the principle of Faraday’s law of electromagnetic induction. The direction of induced current is find with the help of fleming’s right hand rule.

(c) Working :

1. The axle is rotated with help of a machine from outside, the coil starts rotating.
2. On rotating the axle, the branch moves upward and branch moves downwards hence, coil rotates clockwise.
3. According to Fleming’s right hand rule, electric current flows in the direction .

Then galvanometer attached shows a deflection.

1. After half rotation, the branch and exchange their positions and the induced current flows as .

(d) This appliance is majorly used in electric motor.

(ii) Saturated :

Unsaturated :

(b)

(c) Homologous series : A series of compounds with similar chemical properties, in which members differ from one another by additional group, is called a homologous series.