Practice Paper 1

(Solved)

General Instructions

Time : 2 Hours

Max. Marks : 40

1. There are 11 questions in the question paper. All questions are compulsory.

, Question no. 1 to 3 is a Case Based Questions, which has four MCQs/Questions. Each question carries one mark.

Section A

, Question no. 4 to 8 are Short Answer Type Questions. Each question carries 2/3 marks.

Section B

, Question no. 9-11 are Long Answer Type Questions. Each question carries 5 marks.

Section C

5. There is no overall choice. However, internal choices have been provided in some questions. Students have to attempt

only one of the alternatives in such questions.

As exact Blue-print and Pattern for CBSE Term II exams is not released yet. So the pattern of this

paper is designed by the author on the basis of trend of past CBSE Papers. Students are advised

not to consider the pattern of this paper as official, it is just for practice purpose.

Section A

1. Read the following and answer the questions from (i) to (iv) given below

A student wants to study the dependence of potential difference (V)on current (I)flowing across a resistor.

He plotted a graph by taking I along X-axis and V along Y-axis of all his observations.

1.0

0.8

0.6

0.4

0.2

0.4

0.6 0.8 1.0

Current (I)

(i) The value of resistance used in the circuit is

(a) 1 Ω

(b) 2 Ω

(d) 0.5 Ω

(ii) The inverse of the slope of V-Icurve gives

(a) resistance

(b) conductance

(d) resistivity

(iii) The correct representation of Ohm’s law is

(a) V

∝¹

(b) I ∝

(d) I ∝ V

(iv) His friend noticed some observations from this demonstration as follows

1. The slope of the line gives the resistance of a conductor.

2. Motion of electrons through a conductor is retarded by its resistance.

3. All conductors do not obey Ohm’s law.

Which of the following observation(s) is/are correct?

(a) 1 and 2

(b) 2 and 3

(d) 1, 2 and 3

Read the following and answer the questions from

What is the use of the variable resistor in the circuit in

(i) to (iv) given below

the Ohm’s law experiment shown below?

Sex-determination is the method by which

distinction between males and females is

established in a species. The sex of an individual is

determined by specific chromosomes. In human

beings, it is determined as follows

Sperms

Egg

and

I. To change the voltage across the fixed resistor.

X X

X Y

II. To change the resistance across the fixed resistor.

III. To change the current flowing through the fixed

(i)

In XX-XY type of sex-determination,

resistor.

(a) females produce two different types of gametes

(a) Only I

(b) Only III

(b) males produce two different types of gametes

(d) I, II and III

(d) male produces gametes with X-chromosome only

Read the following and answer the questions from

(i) to (iv) given below

(ii)

A couple has six daughters. What is the possibility

of them having a girl child next time?

In modern periodic table, some properties show a

(a) 10%

(b) 90%

(d) 50%

regular trend when we move along a period from

left to right or in a group from top to bottom.

(iii)

Number of chromosome present in the egg cell of a

human female is

Atomic size refers to the radius of an atom. It may

(a) 23 pairs

(b) 23

be visualised as the distance between the centre of

(d) 22 pairs

the nucleus and the outermost shell of an isolated

atom. It is measured in picometres.

(iv)

Choose the incorrect statement from the following

set of statements.

About 75% of all elements in one periodic table are

metals. The most common metal found in the

I. XX-XY type of sex-determination is the example of

male heterogamety.

Earth’s crust is aluminium. The non-metals also are

some of the most abundant elements in the

II. XX-XY type of sex-determination is the example of

universe including the Earth’s crust, the

female heterogamety.

atmosphere and the human body.

III. There are always 50% chances of having a baby girl

The position of three elements A, B and C in the

child.

periodic table are shown below

IV. Changes in the non-reproductive tissues can be

passed on to the DNA of the germ cells.

Group 16

Group 17

Codes

—

(a) I and III

(b) II and IV

—

(d) I and III

—

Sex of human child is determined by

(a) size of the egg

(b) size of the sperm

(i) State whether A is a metal or non-metal.

(d) type of the egg

(ii) State whether C is more reactive or less reactive

than A.

Section B

(iii) Will C be larger or smaller in size than B?

4. Choose the kind of chemical bonding (ionic bond,

(iv) Which type of ion- cation or anion, will be formed

covalent bond, both ionic and covalent bonds)

by A?

present in the following compounds. Potassium

chloride, magnesium oxide, sulphuric acid,

ammonium hydroxide, zinc sulphide, phosphorus

What are metalloids? Give examples.

trichloride (PCl

)

[2 M]

Section C

Write the name and structure of a saturated

compound in which the carbon atoms are

(i) Which is the better way to connect lights and other

arranged in a ring. Give the number of single

appliances in domestic circuit, series connection or

bonds present in this compound.

[2 M]

parallel connection? Justify your answer.

(ii) An electrician has made electric circuit of a house in

Differentiate between pollen tube and style.

[2 M]

such a way that, if a lamp gets fused in a room of the

For the current carrying solenoid as shown below,

house, then all the lamps in other rooms of the

draw magnetic field lines and give reason to

house stop working. What is the defect in this type

explain that out of the three points A, B and C at

of circuit wiring? Give reason.

which point, the field strength is maximum and at

which point, it is minimum.

Three incandescent bulbs of 100 W each are

connected in series in an electric circuit. In another

set of three bulbs of the same wattage are connected

in parallel to the source.

(i) Will the bulb in the two circuits glow with the same

[3 M]

brightness? Justify your answer.

(ii) Now, let one bulb in both the circuits get fused. Will

Diagram shows the lengthwise section of a current

the rest of the bulbs continue to glow in each circuit?

carrying solenoid.

Give reason.

⊗ Indicates current entering into the page,

10.

Differentiate between monohybrid and dihybrid

crosses with the help of an example.

• Indicates current emerging out of the page.

Explain the term ‘regeneration’ as used in relation to

reproduction of organisms. Describe briefly how

regeneration is carried out in multicellular organisms

Decide which end of the solenoid A or B, will

like Hydra?

behave as North pole. Give reason for your

11.

(i) How can pregnancy be prevented surgically?

answer. Also, draw field lines inside the

solenoid.

[3 M]

(ii) Study the diagram given below

Give an example of each of the following

(i) A carbon compound containing two double

bonds.

(ii) A molecule in which central atom is linked to

three other atoms.

(a) Identify the process.

(iii) A compound containing both ionic and covalent

bonds.

[3 M]

(b) Which organism uses the above method for

reproduction?

Define homologous series. Examine it with an

process of fragmentation?

example. Will there be any change in their physical

properties? Give reason for your answer.

[3 M]

(i) Why should biodegradable and non-biodegradable

wastes be discarded in two separate dustbins?

8. Give any three points of differentiation between

(ii) Why do we exemplify crop fields as artificial

acquired and inherited characters with one

ecosystem?

example each.

[3 M]

Explanations

(i)

(a) The slope of V-I graph gives resistance.

(ii)

(d) When a sperm having an X-chromosome fuses with

the egg, the zygote formed will develop into a female

0.4

−

0.4

∴ Resistance =

= 1Ω

baby whereas when a sperm having Y-chromosome

0.4

−

0.4

fuses with the egg, the zygote formed will develop into

(ii)

(b) The inverse of the slope of V-I curve gives

a male baby. Thus, there are always 50% chances of

conductance. i.e.

having a girl child by the couple.

(iii)

(d) Gametes are haploid in nature, i.e they contain half

= Conductance (σ)

Slope Resistance(R)

the number of chromosomes as compared to other

somatic cells. Human beings have 23 pairs of

(iii)

(d) The correct representation of Ohm’s law is I ∝ V. It

chromosomes. Therefore, the egg cell (gamete) contains

states that current flowing through the conductor is

23 chromosomes only.

directly proportional to the potential difference

(iv)

(b) Statements II and IV are incorrect and can be

applied across the conductor.

corrected as

(iv)

(d) All the observations are correct. The slope of the

^● XX-XY type of sex-determination shows male

line in V-I graph gives the resistance of a conductor

heterogamety and female homogamety.

whereas motion of electrons through a conductor is

^● Changes in the non-reproductive tissues cannot be

retarded by its resistance.

passed on to the DNA of the germ cells.

All conductors do not obey Ohm’s law i.e., Ohm’s

Or (c) Sex of a human child is determined by the type of sperm

law is not universal.

(X or Y) that fuses with egg during fertilisation.

(c)

Ohm’s law states that the resistance (ratio of the voltage

A sperm with an X-chromosome will produce a baby girl and

across the fixed resistor to the current flowing through

that with Y-chromosome will produce a baby boy on

it) is constant. The aim of Ohm’s law experiment is to

fertilisation.

find the resistance of a fixed resistor. By adjusting the

variable resistor.

Covalent

Both ionic and

• the voltage across the variable resistor and fixed

Ionic bond

bond

covalent bond

resistor will change.

(i) Potassium chloride

Phosphorus

Sulphuric acid

• the total resistance in the circuit will change

trichloride

Ammonium

leading to a change in current flowing through the

(ii) Magnesium oxide

hydroxide

fixed resistor.

(iii) Zinc sulphide

(i)

Since, A belongs to group 17 and has 7 valence

Or Cyclopropane

electrons so it is a non-metal because it will gain one

electron to complete its octet.

(ii)

C lies below A and belong to the same group. As we

move down a group, the size increases and

C C

electronegative character decreases. With the decrease

in electronegative character, the electron accepting

Cyclopropane contains three C⎯C single bond and six C⎯H

tendency and hence the reactivity of non-metals

single bond.

decreases, so C is less reactive than A.

Total 9 single bonds are present in cyclopropane.

(iii)

C and B both belongs to the same period therefore, C is

5. Differences between pollen tube and style are as follows

smaller than B in size because as we move left to right

in a period, atomic size decreases due to increased

Pollen Tube

Style

effective nuclear charge.

A tube growing out of pollen The middle elongated

(iv)

As discussed in that element A has a tendency to gain

grain when it reaches stigma. part of the carpel, i.e.

electron to complete its octet. It needs to take up one

female part of a flower.

electron, so it will form anion (A⁻).

It transports male gametes

The attachment of stigma

Or These are some elements which exhibit the properties

from pollen grains to ovules.

to the ovary.

of both metals and non-metals. These are called

metalloids. In modern periodic table, a zig-zag line

6. Magnetic field lines due to a solenoid

separates metals from non-metals.

The border line elements—boron, silicon, antimony are

intermediate in properties, so they are called mtalloids

or semi-metals.

(i)

(b) In XX-XY type of sex-determination (human’s sex-

determination), the males produce two different types

of gametes, one contains X-chromosome whereas the

other contains Y-chromosome.

In case of an ideal solenoid, magnetic field strength is

(i) Parallel connection is a better way to connect lights and

maximum at point A and is minimum or zero at point B. This

other appliances in domestic circuit.

is because the magnetic field is strong, where magnetic field

It is because

lines are crowded and is weak, where magnetic field lines

(a) when we connect a number of devices in parallel

are far apart. At the point C, the density of the field lines is

combination, each device gets the same potential

less than that of point A but greater than that of point B. So,

as provided by the battery and it keeps on

the order of magnetic field at points A, B and C is

working even, if other devices stop working.

B <B <B

(b) parallel connection is helpful when each device

Or From diagram, we can see that current is entering from A

has different resistances and requires different

and emerging out from B.

current for its operation as in this case the

current divides itself through different devices

unlike series connection.

(ii) Electrician has made series connection of all the lamps

in electric circuit of house because of which, if one

lamp gets fused, all the other lamps stop working.

This is due to the fact that when devices are connected

in series, then if one device fails, the circuit gets broken

Thus, using right hand thumb rule, direction of magnetic

and all the devices in that circuit stop working.

field lines is from B to A. We know that, magnetic field lines

(i) Let us assume that the resistance of each bulb be R.

move from North to South direction. Thus, B represents

The circuit diagram in two cases may be drawn as given

North pole or A represents South pole.

below

B₁

(i) Carbon dioxide (CO₂)

••

A₁

(ii) Ammonia molecule (NH₃) H — N— H

B₂

B₁

B₂

B₃

⏐

A₂

B₃

A₃

(iii) Ammonium chloride (NH Cl)contains both ionic and

covalent bonds.

⎡

⎤

⎢

⎥

Equivalent resistance in series combination

−

⎢H⎯N⎯H⎥ Cl

RS =R+R+R =3R

, voltage = V

⎢

⎥

⎢

⎥

Let current through each bulb in series combination be I₁.

Or A series of similarly constituted compounds in which the

By Ohm’s law, V = I

×3R

⇒ I

members present have the same functional group and

similar chemical properties and any two successive members

∴Power consumption of each bulb in series combination,

in a particular series differ in their molecular formula by

⎞

P =I2(3R)

=⎜

⎟

×3R = V

= V²

...(i)

(⎯

CH )unit, is called a homologous series, e.g. alkane

⎝ 3R⎠

series C H

2n+ 2 .

For parallel circuit, the resistance of each bulb = R

CH₄

Methane

C H2

Ethane

Voltage across each bulb = V

C H

Propane

C H

Butane

[Q same voltage in parallel combination]

∴ Power consumption of each bulb in parallel combination

C H

Pentane

is given by

With increase in the molecular mass, a gradual change in

their physical properties is seen. e.g. The melting and

P2 = ^V2

…(ii)

boiling points increase with increasing molecular mass.

From Eqs. (i) and (ii), we get

8. Differences between acquired and inherited traits are as

V2/R)

follows

= (

(

V2/3R)

Acquired Characters

Inherited Characters

⇒ V

⇒ P =3P

R V²

They develop in the organism They are received by the

during their lifetime.

organisms from their parents.

Therefore, each bulb in parallel combination glows 3 times

brighter than that of each bulb in series combination.

They do not bring any change They bring about certain changes

(ii) When one bulb gets fused then in series combination, the

in the genes of organisms.

in the genes of the organisms.

circuit gets broken and current stops flowing, whereas in

They are lost with the death of They are transferred to the next

parallel combination, same voltage continues to act on the

the individual, e.g. intelligence. generation, e.g. free and fused

remaining bulbs and hence other bulbs continues to glow

earlobes.

with same brightness.

10. Differences between monohybrid and dihybrid crosses are

as follows

Regeneration is used in relation to reproduction because

Monohybrid cross between homozygous tall plant and

reproduction is the process by which a living organism is able

homozygous short plant is shown below

to produce new individuals of its own kind likewise

regeneration is the ability of some organisms to give rise to

Monohybrid cross A hybridisation cross in which

new organisms when the individual is cut or broken up into

inheritance of only one pair of

many pieces.

contrasting characters is studied.

It is seen in Hydra and Planaria.

Dihybrid cross

A cross in which inheritance of two

Regeneration in Multicellular Organism like Hydra

pairs of contrasting characters is

(i)

It is carried out by specialised cells.

simultaneously studied.

(ii)

When Hydra is cut or broken up into many pieces, these

specialised cells proliferate and make large number of

cells.

(iii)

From this mass of cells, different cells undergo changes

to become various cell types and tissues.

(iv)

These changes take place in an organised sequence

referred to as development thereby making each piece

to grow into a separate individual.

Tall

Short

All tall offsprings

11.

(i)

When vas deferens in males are blocked surgically,

(TT)

× (tt)

(Tt)

sperm transfer is be prevented. Similarly, when

P×P

F₁

Fallopian tubes are blocked in females the egg will

not be able to reach the uterus therby preventing

pregnancy.

(ii)

(a) The process in the figure depicts binary fission in

Amoeba, a method of asexual reproduction.

(b) Binary fission also occurs in Euglena and Paramecium,

etc.

Tall

Short

F₁

F₂

follows

(Tt)

(TT)

(Tt)

(tt)

Fission

Fragmentation

Dihybrid cross between pure breed of plants having Round

and Green seed and Wrinkled and Yellow seeds is shown

It is the division of parent

It is the division of

below

body into two identical

parent body into two

daughter cells.

or more small fragments.

Parents

RRyy

rrYY

(Round green)

(Wrinkled yellow)

It occurs in unicellular

It occurs only in

↓

organisms or multicellular

multicellular organisms

Gametes

organisms with simple body

with complex cellular

organisation.

organisations.

F1-generation

RrYy

e.g. Amoeba, Plasmodium

e.g. Spirogyra (algae)

(Round yellow)

(protozoan)

F₁

(i)

Biodegradable materials are broken down by

microorganisms in nature into simple harmless

substances. Non-biodegradable materials need a

different treatment like heat and temperature for

disposal and hence, both should be discarded in two

RRYY

RRYy

RrYY

RrYy

different dustbins.

(ii)

Artificial ecosystems are those ecosystems which are

RRYy

RRyy

RrYy

Rryy

modified and managed by human beings.

Crop fields are man-made. Here plants do not grow

RrYY

RrYy

rrYY

rrYy

naturally rather most of the plants are grown by humans

according to the season, type of soil, etc.

RrYy

Rryy

rrYy

rryy

In crop fields, the land is managed, soil is prepared

Ratio

for sowing seeds, then irrigated and further

-generation

315 round yellow

progress is also kept under observation for getting good

108 round green

yield.

101 wrinkled yellow

32 wrinkled green

This is why, crop fields are known as artificial ecosystem.

556 seeds