The below Questions have been added to the respective units wherever necessary. The answers have been prepared in concise and simple language to suit my Govt school children
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| JKBOSE Class 9th Term II Science Model Paper Solved, Mufawad |
1 Q. Define the Universal law of Gravitation and
state its importance?
Ans: Gravitation is a non
contact force of attraction between two bodies by virtue of their mass.
Universal law of Gravitation
The law states that every object attracts other object mutually.
This force of attraction is directly proportional to product of the masses of
two bodies i.e M1, M2
=>
F ∝ M1
× M2
It is also Inversely proportional to square of distance, "R" between
them.
=>
F ∝
1
2
R
=>
F ∝ M1
× M2
2
R
=> F
= G M1× M2
2
R
The "G" is universal gravitation constant. Its
-11 2 2
value is 6.67 × 10 Nm/ kg.
Importance of Universal Law of Gravitation:
The importance of the universal law of gravitation is as
follows:
It explains the motion of planets around the sun.
It helps in determining the trajectory of astronomical
bodies and to predict their motion.
It also explains rainfall, the motion of water in the
oceans, rivers etc.
2. Q. An object is vertically thrown upwards and rises
to the height of 10 m. Calculate
i.
The velocity with which was thrown upwards
ii.
The time taken to reach highest point
Ans: Given;
Distance (S) = 10 m
Final velocity = 0 m/s
g = 9.8 m/s2
To calculate velocity with which was thrown upwards, We know
V2 – U2 = 2gS
V2 – 02 = 2 x 9.8
x 10
V2 = 196
V = √196
V = 14 m/s2
To calculate Time taken to reach Highest point, We know
V = U + gT
0 = 14 + 9.8 x T
T = 14/9.8
T = 1.42 S
3. Q. Explain how sound is produced by your school bell?
Ans: The sound is form of energy which gives us sensation of
hearing.
The sound is produced by our school bell is due to vibrations
that are produced in it when hit by a rod. The sound produced travels in the
form of waves.
These sound waves are longitudinal waves. When they travel in
air, the air molecules vibrate back and forth in the same direction as wave.
At one point air particles come closer, there is decrease of
volume and increase in density which causes compression.
At alternate point, the air particles move apart from one
another, there is increase in volume and decrease in density which causes
rarefaction.
Thus sound waves travel in the form of compressions and
rarefactions.
4. Q. What work is to be done to increase the velocity
of car from 30 km/h to 60 km/h if the mass of car is 1500 kg.
Ans: Given,
V1 = 30 km/h i.e.
8.34 m/s ( x 5/18)
V2 = 60 km/h i.e.
16.6 m/s ( x 5/18)
Mass = 1500 kg
We know that work done to increase velocity will change the
kinetic energy of the car, Thus
Work Done (W) = Final Kinetic Energy - Initial Kinetic energy
W = ½ MV22 - ½ MV12
W = ½ x 1500 x (16.6)2 - ½ x
1500 x (8.34)2
W = 204815
- 52166
Thus Work Done = 152649 Joules.
5. Q. The SI unit of Work done is
a.
Joule b.
Newton c. Dyne d. Tesla
Ans: a. Joule
6. Q. Rate of doing work is
a.
Power b.
Energy c. Kinetic energy d. Pressure
Ans: a. Power
7. Q. The Speed of sound in a medium depends on
a. Temperature b. Pressure c. Both A and B d. Velocity
Ans: c. Both A and B
Chemistry
Q. Explain Rutherford’s Model of Atom and write its drawbacks
Ans: Rutherford did α- particle
scattering experiment.
This experiment led to the Discovery of Nucleus and Rutherfords model of atom.
In this experiment, he hit a thin gold foil with α Particles. The
results were as:
i. Most α Particles passed straight.
ii. Some particles were deflected.
iii. Very few bounced back.
Based on it, he gave a model of atom called Rutherfords model of atom. It
suggested:
i. Most space in atom is empty.
ii. The positive charge takes small space.
iii. Positive charge is concentrated in small volume.
He concluded that atom has small positive nucleus and electons revolve around
it in orbits.
Drawbacks:
Rutherford said electrons revolve around nucleus in orbits. However in a
circular orbit, a charged particle will loose energy due to acceleration and
fall into nucleus.
Ans: Electron:
Electron was discovered by J.J Thomson. Electron has negative charge and has
very low mass.
The mass of electron is 1/1840 U and its
- 19
charge is 1.6 × 10 C.
Proton: Proton was discovered by E. Goldstein. Proton is positively
charged and has high mass.
The mass of proton is 1840 times than
-19
electron and its charge is 1.6 × 10 C.
Neutron: Neutron was discovered by Chadwick. Neutron has no charge and
its mass is equal to proton.
10Q. Define the following with examples
a.
Isotopes
b. Isobars
Ans: Isotopes
Isotopes are different forms of same element that have
different mass number.
They have different physical properties but same chemical
properties.
Examples: Hydrogen has three isotopes i.e
1 2 3
Proteum H1 , Dutreum H1 , Tritreum H1
Isobars
Isobars are different elements which which have same mass
number.
They have same number of protons plus neutrons.
40 40
Example: Calcium , C 20 , Argon, Ar 18 are Isobars.
11Q. Write down the formula of Aluminium Oxide and
Magnesium Oxide
Ans: Aluminium Oxide = Al2O3
Magnesium Oxide = MgO
12Q.
Co is the symbol of:
a.
Carbon b.
Cobalt c. Magnesium d. Cadmium
Ans: b. Cobalt
1Q. The Avogadro’s number is
Ans: 6.022 x 10 23 Particles
1q. The valency of chlorine is
a.
Zero b.
One c. Two d. Three
Ans: b. One
Biology
15Q. What are the desirable agronomic characteristics
of Crop Improvement?
Ans: Desirable agronomic characters for crop improvement are:
1. Tallness in fodder crops and dwarfness in cereals.
2. Wider adaptability across different environments.
3. High yeild and high nutrition.
4. Diseases resistance.
16Q, What is genetic manipulation? How is it useful
in agricultural practices?
Ans: The use of biotechnology to induce certain traits at
genetic level in crops is genetic manipulation.
These traits include resistance to diseases, High yeild.
Genetic manipulation can be achieved by hybridization, DNA
recombinant technology.
Such practices help to create high yeilding varieties of crop.
It helps to create diseases resistant varieties of crop.
They helps to create drought and heat resistant varieties of
crop.
17Q. Write down the symptoms of drug addiction?
Ans: There are many signs
which helps us to know if a person is involved in drug abuse;
1. Insomnia, loss of appetite and loss of weight.
2. Very aggressive behaviour, mood swings and isolation from family
and friends
3. Depression and loss of interest in day to day activities.
4. Bloodshot in eyes with smaller pupil.
5 Unstable gait, slurred speech.
6. Health issues, tremors, fits or seizures.
1Q. Write the various problems suffered by
adolescents?
Ans: Adolescence is the age
of transition from childhood to adulthood. It is also called as
'Teenage.'
1. Adolescents may have childhood adulthood conflict.
2. They may have difficulty to adjust with family, relatives,
school.
3. They may have anxieties and fears due to mensuration,
nocturnal discharge etc.
4. They may have acne, loneliness, phobias.
q. Fertilizers supply
i. Nitrogen Potassium ii. Aluminium iii. Iron
iv. Calcium
Ans: . Nitrogen Potassium
20Q. ……………….. Compete for Food, Space and Light
i. Pesticides ii. Weeds
iii. Microbes iv. Fertilizers
Ans: ii. Weeds
21Q. AIDS stands for:
Ans: Acquired Immuno Deficiency Syndrome
22Q. The vital organ which is affected by Tobacco is
i.
Lungs
ii. Stomach iii. Kidneys iv. Liver
Ans: Lungs
