Optional Math SEE Model Question Set-1 With Answers

1 Revision Nepal

SEE – Model Questions 2078


Grade : X F.M. : 75

Subject: Science


Group-A (15×1=15)

Q.1             Write short answer of the following questions.

a.                   The value of universal Gravitational Constant is 6.67×10-11 Nm2/kg2. What does it mean?

Ans: This means the force of gravitation between two units of masses keeping/existing at a unit distance from their centre is 6.67×10-11N.

b.                   What is torricellian vacuum?

Ans: The vacuum which is created at the top of mercury barometer which was invented by Torricelli mercury barometer which was invented by Torricelli.

c.                   Define biomass

Ans: The organic material/substance which can be converted into energy.

d.                   Which metals are used to make nichrome wire? Ans: Chromium (40%) and nickel (60%).

e.                   What is the distance of far point & near point for normal eye? Ans: Far point is infinity and near point is 25 cm.

f.                    Define lanthanides.

Ans: One of the series of inner-transition elements from number (58-71) after Lanthum is called Lanthanides

g.                   What is paraffin?

Ans: The saturated hydrocarbon and another name for alkanes are paraffin.

h.                   Write down the boiling point of aluminum and gold. Ans: Aluminum = 1800°C Gold = 2610°C

i)                    What is saponification?

Ans: The process by which soap is prepared by the reaction of animals or plants, fat with sodium hydroxide solution is called saponification.

j)                    Define nuptial flight.

Ans: The flight taken by queen bee to mate with drone bees outside the hive is called nuptial flight.

k)                  What is uric acid?

Ans: The compound formed by carbon, hydrogen, nitrogen and oxygen whose molecular formula is C5H4N4O3 is uric acid.

l)                    What sex chromosomes are found in male and female? Ans: In male XY and in female XX sex chromosome.

m)                Write the type of sexual reproduction in hydra and spirogyra. Ans: Hydra-budding, Spirogyra-fragmentation.

n)                  What is scion?

Ans: The stem of a plant which is used in grafting is called Scion or the shoot system of a plant that is used for grafting.

o)                  What is geological time scale?

Ans: A time scale that includes the earth’s history from its origin to the present is called geological time scale.

Group-B (13×2=26)

Q.2             Write down the two conditions in which the body becomes weightless. Ans: Two conditions for weightlessness:

i)              The body should fall freely only under the influence of the force of gravity.

ii)            If the body is at the earth’s center or in the space at null point (g=0)

Q.3             Study the given figure and answer the following.

wt. f stone in liquid= 7 N wt. of liquid displaced = 2N

i)              What is the actual weight of the stone?

Ans: Actual weight is weight in air

i.e. Wa = Weight in Water + Weight of displaced liquid

= 7N + 2N

= 9N

ii)            State the principle in which this experiment is based on?

Ans: The given arrangement works on Archimedes principle which states that, "An object fully or partially submerged into a liquid experiences the upthrust equal to the weight of water displaced by it."

Q.4             Energy crisis may occur in the world in near future. "Justify this statement with two reason."

Ans: i) Due to overpopulation, urbanization & industrialization, the demand of sources of energy are increasing in alarming rate.

iii) 80% energy are obtaining from non-renewable sources.

Q.5             An electric heater draws a current of 10A from 220V supply. What is the cost of electricity using that a heater for 7 hours per day in a month? The rate of unit cost is Rs.10.

Ans: Given,

Current drawing (I) = 10A Potential difference (P.d.) = 220V For a heater,

No. of heater (n) = 1 Time (T) = 7 hr/day Power (P) = I×V

= 10×220

= 2200W

= 2200/1000 KW

= 2.2 KW


Electrical energy consumed in one day = n×p×T

= 1×2.2×7

= 15.4 KW/hr

= 15.4 unit Cost per unit (R) = Rs.10

Cost for one day = Rs.10×15.4 = Rs.154 Cost for one month = 30×154 = Rs.4620

Q.6             Which one is more reactive in between fluorine and chlorine, why?

Ans: Fluorine is more reactive in between fluorine and chlorine because fluorine has small atomic size and hence more electronegativity which helps to attract the electron more easily than chlorine.


Write the structural formula of glycerol and write any one use of acetylene. Ans: Structural formula of gycerol is,

Use of acetylene – used in the production of polyethylene plastics or other matched answer.

Q.8             State any two causes of chemical pollution.

Ans: i) Production of basic metals

ii)           motor vehicles

iii)         textile industry

iv)          production of rubber

Q.9             Two chemical substances A and B when mixed at room temperature react very slowly. Suggest two different ways of increasing the rate of this reaction.

Ans: i) by increasing the temperature

ii) by supplying the more atmospheric pressure.

Q.10         Write the one-one function of given hormones

i)              parathormone ii) progesterone

Ans: i) parathormone = maintains the calcium level in blood

ii)            progesterone = maintenance of pregnancy

Q.11         Write any two points to show the economic importance of silkworm.

Ans: i) by selling the silk obtained from silkworm, we can level up the economic status.

ii) We can get employment opportunity

Q.12         During blood donation, blood is drawn from the vein but not from the artery, why?

Ans: The walls of veins are thinner than arteries. The blood pressure in veins is less than that in arteries. Veins are closer to the surface of skin which make easier by avoiding deep needle plunge just to draw a bit of blood.

Q.13         Write any two differences between male gamete and female gamete. Ans:

Male gamete

Female Gamete

i) sperm cell

i) egg cells

ii) produced by male reproductive


ii) produced by female reproductive



Q.14         The tail of a comet disappears as it moves away from the sun, why?

Ans: The tail of a comet is formed when it reaches nearer to the sun by getting radiation and get evaporates dust gas. So if it moves away from sun it does not get radiation and its tail disappears.

Group-C (6×8=18)

Q.15         The weight of a person on planet ‘A’ is 580N. What will be his weight on the planet ‘B’ whose mass is 6 times and radius is 2 times than that of planet ‘A’?

Ans: Weight of a person on planet ‘A’ (W1) = 580N Mass of the 1st planet = M

Radius of the 1st planet = R the weight of the person is,

F1= GMm/R2

580= GMm/R2 (i)

Weight of a person on planet ‘B’ (W2) = ? Mass of 2nd planet (M2)= 6M

Radius of 2nd planet(R2)=4R Weight of theperson(F2)=GM2m/R22


=6/4 x (GMm/R2)

=1.5 x 580 [from eqn—- i]

= 870N

Q.16         Answer the following question on the basis of the given table.



Specific heat capacity


470 J/kg°C


910 J/kg°C


380 J/kg°C


a)             The sp. heat capacity of substance ‘C’ is 380 J/kg’C, what does it mean?

Ans: This means 380J heat energy is required to raise the temperature of 1kg substance C by 1’C.

b)            If equal heat is given to equal masses, which one will have the highest temperature, why?

Ans: Substance C will have highest temperature as it has the lowest specific heat capacity.

c)            Which substance will penetrate to the greatest depth if each with equal mass are put on a wax-slab after heating to 100’C each, why?

Ans: Substance B will penetrate the deepest as it has highest value of S nd it will be hotter for longest period.

Q.17         A compound given Ca+ ion and OH ion when dissolved in water.

i)              What happens when this compound reacts with ammonium salt on heating? Write with chemical equation.

Ans: The compound is calcium hydroxide Ca(OH)2. Ammonia gas is formed.

2NH4Cl + Ca(OH)2 CaCl2 + 2NH3 + H2O

Salt and water will be formed

ii)            Write one use of this compound.

Ans: To reduce the hyperacidity of stomach, it is used

iii)          What happens when this compound is reacted with hydrochloric acid? Ans: 2HCl + Ca(OH)2 CaCl2 + 2H2O

Q.18         Which glass is formed if the mixture of silica, potassium carbonate and lead monoxide is heated. Write its one special property and two uses.

Ans: Lead crystal glass is formed. It has high refractive index.


i)              To make lenses, prisms, electric bulbs.

ii)            To make TV & radar tubes.

Q.19         What is tissue culture? How it is done? Write any two importance of vegetative propagation.

Ans: Tissue culture is modern technique of vegetative propagation. With the help of culture solution, it is done.

Importances of vegetative propagation,

i)              it is cheap & rapid method relative to a long period of seed dormancy.

ii)            The plants which do not produce viable seeds can be easily propagated by this method. eg. banana, rose etc.

Q.20         Write any three adverse effects caused by soil pollution.

Ans: Adverse effects caused by soil pollution, are

i)              affects the plants as well as any other forms of life negatively.

ii)            degrades the quality of soil such as texture, water holding capacity, porosity etc.

iii)          Kill various useful animal living inside the soil.

Group-D (4×4=16)


i) What is the defect of vision of the eye in the given figure?


ii) Write the causes of this defect (any two).

Ans: Elongation of eye ball, decreasing the focal length of eye lens etc.

iv)          How can we correct this defect?

Ans:)By using the concave lens of suitable focal length.

v)            Draw the diagram for its remedy. Ans:




i)              Which gas is collected in gas jar?

ii)            What is Y in given figure? Why is it used?

i)              How is urea prepared from this gas? Write with chemical equation.

Ans: i) Ammonia gas

ii)           Y is lime tower.

Lime tower (CaO) is used to absorb the water which is in moisture from during the chemical reaction produced along with ammonia gas.

iii)         Urea is prepared when ammonia gas reacts with carbon dioxide gas under pressure and temperature at about 1500°C.

Chemical equation

2NH3 + CO2


NH2–CO–NH2 + H2O.


Draw a chart showing the crossing between tall and dwarf pea plants till F2 generation. Find out the genotypic and phenotypic ratio of F2 generation. When the mating of black and white rats takes place all the off spring produced in first generation are black, why?


Here, Phenotypic ratio in F2-generation Tall: Dwarf= 3:1

Genotypic ratio = pure tall: hybrid tall: pure dwarf= 1:2:1

When the mating of black and white rets takes place all the off spring produced in first generation are black because among black & white colour, black is dominant over white and according to law of dominance only one characters is seen is first generation.

Q.24         Draw a neat diagram to show the different layers of atmosphere and write the adverse effects of ozone layer depletion.


The effects of ozone layer depletion are as follows,

a.  damage to DNA and leads to mutation

b.   damage to skin cells

c.  ageing of skin

d.   cause various types of cancers

e.  cataract


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