Sunday, October 2, 2022

Samacheer kalvi 7th Science Term 2 all one marks with answer!

 I. Choose the correct answer. 

1. International unit of measuring temperature is _________.

  1. Kelvin    b) Fahrenheit    c) Celsius    d) Joule

Ans: a) Kelvin

2. In thermometer when bulb comes in contact with hot object, liquid inside it

  1. Expands     b) contracts    c) remains same    d) none of above

Ans: a) expands

3. The body temperature of a healthy man is; 

  1. 0oC    b) 37oC    c) 98oC    d) 100o

Ans: b) 37oC

4. Mercury is often used in laboratory thermometers because it ______.

  1. Is a harmless liquid

  2. Is silvery in colour and is attractive in appearance

  3. Expands uniformly

  4. Is a low cost liquid

Ans: c) expands uniformly

5. Which of the following temperature conversions is incorrect 

K (Kelvin) = oC (Celsius) + 273.15



oC

K

a

-273.15

0

b

-123

+150.15

c

+127

+400.15

d

+450

+733.15

Ans: d) 

6. In the circuit diagram below, 10 units of electric charge move past point x every second. What is the current in the circuit _______

  1. 10 A    b) 1 A    c) 10 V    d) 1 V

Ans: a) 10 A

7. In the circuit shown, which switches (L, M or N) must be closed to light up the bulb?

  1. Switch L only

  2. Switch M only

  3. Switch M and N only

  4. Either switch L or switches M and N

Ans: d) Either switch L or switches M and N

8. Small amounts of electrical current are measured in milliampere (mA). How many milliampere are there in 0.25 A?

  1. 2.5 mA    b) 25 mA    c) 250 mA    d) 2500 mA

Ans: c) 250 mA

9. In which of the following circuits are the bulb connected in series?

Ans: b)

10. When a woolen yarn is knitted to get a sweater, the change can be classified as _____.

  1. Physical change    b) chemical change    c) endothermic change    d) exothermic change

Ans: a) physical change

11. __________ of the following are endothermic changes. 

  1. Condensation and melting

  2. Condensation and freezing

  3. Evaporation and melting

  4. Evaporation and freezing

Ans: a) condensation and melting

12. The chemical change is _________.

  1. Water to clouds

  2. Growth of a tree

  3. Cow dung to bio-gas

  4. Ice-cream to molten ice-cream

Ans: c) cow dung to bio-gas

13. _________ is an example of a periodic change. 

  1. Earthquake.

  2. Formation of rainbow in sky

  3. Occurrence of tides in seas

  4. Showering of rain

Ans: a) Earthquake

14. ___________ is not a chemical change. 

  1. Dissolution of ammonia in water

  2. Dissolution of carbon-di-oxide in water

  3. Dissolution of oxygen in water

  4. Melting of polar ice caps

Ans: d) Melting of polar ice caps

15. Basic unit of life.

  1. Cell    b) Protoplasm    c) Cellulose    d) Nucleus

Ans: a) Cell

16. I am the outer most later of an animal cell. Who am I?

  1. Cell wall    b) Nucleus    c) Cell membrane    d) Nuclear membrane

Ans: c) Cell membrane

17. Which part of the cell is called the brain of the cell?

  1. Lysosome    b) Ribosome    c) Mitochondria    d) Nucleus

Ans: d) Nucleus

18. _______ helps in cell division 

  1. Endoplasmic reticulum    b) Golgi complex    c) Centrivole    d) Nucleus

Ans: c) Centriole

19. Suitable term for the various components of cell is_____.

  1. Tissue    b) Nucleus    c) Cell    d) Cell organelle

Ans: d) Cell organelle

20. The following characteristics are essential for classification. 

  1. Similarities    b) Differences    c) Both of them    d) None of them

Ans: c) Both of them

21. Approximately ________ species of living organisms found in the earth. 

  1. 8.7 million    b) 8.6 million    c) 8.5 million    d) 8.8 million

Ans: a) 8.7 million

22. The largest division of the living world is ________.

  1. Order    b) Kingdom    c) Phylum    d) Family

Ans: b) Kingdom

23. Who proposed the five kingdom of classification?

  1. Aristotle    b) Linnaeus    c) Whittaker    d) Plato

Ans: c) Whittaker

24. The binomial name of pigeon is ________.

  1. Homo sapiens    b) Rattus rattus    c) Mangifera indica    d) Columbo livia

Ans: d) Columbo livia

25. Tux paint software is used to _____.

  1. Paint    b) Program    c) Scan    d) PDF

Ans: a) Paint

26. Which toolbar is used for drawing and editing controls in tux paint software?

  1. Left side: Toolbar

  2. Right side : Toolbar

  3. Middel : Tool bar

  4. Bottom : Toolbar

Ans: a) Left side : Toolbar

27. What is the shortcut key for undo option?

  1. Ctrl+Z    b) Ctrl+R     c) Ctrl+Y    d) Ctrl+N

Ans: a) Ctrl+Z

28. Tux Math software helps in learning the ______. 

  1. Painting    b) Arithmetic    c) Programming    d) Graphics

Ans: b) Arithmetic

29. In Tux Math, Space cadet option is used for _____.

  1. Simple addition    b) Division    c) Drawing    d) Multiplication

Ans: a) Simple addition


II. Fill in the blanks.

1. Doctor uses clinical thermometer to measure the human body temperature. 

2. At room temperature mercury is in liquid state. 

3. Heat energy transfer from hotter object to colder object.. 

4. -7oC temperature is less than 0oC temperature. 

5. The common laboratory thermometer is a mercury thermometer.

6. The direction of conventional current is opposite to electron flow. 

7. One unit of coulomb is charge of approximately 6.242 x 1018 protons or electrons.

8. Ammeter is used to measure the electric current. 

9. In conducting materials electrons are loosely bounded with atoms. 

10. S.I unit of Electrical conductivity of a conductor is Siemens / meter (S/m).

11. Filling up a balloon with hot air is a physical  change. 

12. Stretching gold coin into a ring is a physical change. 

13. Opening a gas cylinder knob converts liquid fuel into gaseous fuel. This is an example of physical change. 

14. Spoiling of food is a chemical change. 

15. Respiration is a exothermic chemical change.

16. The jelly like substance present in the cell is called cytoplasm.

17. I convert the Sun’s energy into food for the plant. Who am I? Chloroplast

18. Mature Red blood cell do  not contain a Nucleus.

19. Unicellular organisms can only be seen under a Microscope.

20. Cyctoplasm plus necleoplasm is equal to protoplasma.

21. Gaspard Bauhin in 1623, introduced the binomial nomenclature. 

22. Species is the basic unit of classification. 

23. Fungi are non-green and non-photosynthetic in nature. 

24. The binomial name of onion is Hum sativum.

25. Carolus Linnaeus is known as the Father of Modern Taxonomy.


III. Match the following.

i) Clinical thermometer

Kink

ii) Normal temperature of human body

37oC

iii) Heat

A form of energy

iv) Boiling point of water

100oC

v) Melting point of water

0oC


1

Cell

A device which converts chemical energy into electrical energy

2

Switch

Used to open or close a circuit

3

Circuit

A complete path for the flow of an electric current

4

Miniature circuit Breaker

Reset by hand, circuit becomes complete once again

5

Fuse

Safety device used in electric circuit


A

B

C

1. Melting

Change of state from solid to liquid

Ice cube to water

2. Condensation

Change of state from gas to liquid

Steam to water drops

3. Evaporation

Change of state from liquid to gas

Water to steam

4. Freezing

Change of state from liquid to solid

Formation of ice cube

5. Periodic change

Occurs at regular time intervals

Ticking of clock

6. Non-periodic change

Occurs at irregular time intervals

Collecting flowers


1

Transporting channel

Endoplasmic reticulum

2

Suicidal bag

Lysosome

3

Control room

Nucleus

4

Power house

Mitochondria

5

Food producer

Chloroplast


1

Monera

Bacteria

2

Protista

Eglena

3

Fungi

Moulds

4

Plantae

Neem

5

Animalia

Butterfly


IV. True or False - If False give the correct answer

1. Electron flow is in the same direction to conventional current flow. False

Ans: Electron flow in opposite direction to conventional current flow. 

2. The fuse wire does not melts whenever there is overload in the wiring. False

Ans: The fuse wire will melt whenever there is overload to cut power supply. 

3. In a parallel circuit, the electric components are divided into branches. True

4. The representation of the electric current is A. True

5. The electrical conductivity of the semiconductor is in between a conductor and an insulator. True

6. Cutting of cloth is an example of a periodic change. False

Ans: Cutting of cloth is a physical change

7. Taking a glass of water and freezing it by placing it in the freezer is chemical change. False

Ans: Freezing is a physical change. 

8. A bean plant collecting sunlight and turning it into bean seeds is an example of physical and non-periodic change. False

Ans: Its a chemical change.

9. If the chemical properties of a substance remain unchanged and the appearance or shape of a substance changes it is called a periodic change. False

Ans: It is a physical change. 

10. Tarnishing of silver is an example of endothermic change. False

Ans: Tarnishing of silver is a chemical change. 

11. Animal cells have a cell wall. False

Ans: Animal cell does not have cell wall.

12. Salmonella is a unicellular bacteria. True

13. Cell membrane is fully permeable. False

Ans: Cell membrane is selectively permeable.

14. Only plant cells have chloroplasts. True

15. Human stomach is an organ. True

16. Ribosomes are small organelles with a membrane. False

Ans: Ribosomes are small but does not have membrane. 



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