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Class 9

Explore popular questions from Science for Class 9. This collection covers Science previous year Class 9 questions hand picked by experienced teachers.

Science

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Q 1. A wire carrying a current of 5 A is placed perpendicular to a magnetic induction of 2T. The force on each centimeter of the wire is :

0.1 N

B

10 N

C

100 N

D

1 N

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Q 2. The frequency of alternating current (A.C.) in India is :

50 Hz

B

100 Hz

C

220 Hz

D

440 Hz

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Q 3. Induced electromotive force in a coil does not depend on :

A

number of turns in the coil

B

intensity of the magnetic field

C

relative speed between coil and the magnet

resistance of the coil

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Q 4. A transformer steps up an a.c. supply from 220 to 2200 V. If the secondary coil of the transformer has 2000 turns, the number of turns is its primary coil will be :

200

B

100

C

50

D

20

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Q 5. A step down transformer reduces 220V to 11V. The primary draws 5 A current and secondary supplies 90A. Efficiency of the transformer will be :

A

4.40%

B

20%

C

33%

90%

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Q 6. A transformer is used :

A

to transform electric energy into mechanical energy

B

to obtain suitable dc voltage

C

to transform as into dc

to obtain suitable as voltage

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Q 7. What is increased in a step down transformer ?

A

Voltage

Current

C

Wattage

D

None of these

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Q 8. In circular coil current is flowing in anticlockwise direction, then the direction of magnetic field produced at the centre of coil, will be :

A

in the plane of coil

perpendicular to the plane of coil

C

in the direction of current

D

parallel to any diameter

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Q 9. A current passes through a coil in the anticlockwise direction. The magnetic field at a point on the axis of the coil is :

A

parallel to the plane of the coil

B

perpendicular to the axis of the coil

C

along the axis towards the centre of the coil

along the axis away from the centre of the coil

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Q 10. Current is induced in a coil by electromagnetic induction when :

A

only the coil moves in a magnetic field.

B

only the magnet moves towards the coil.

coil and the magnet move with respect to each other.

D

none of the above.

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Q 11. The transformer voltage induced in the secondary coil of a transformer is mainly due to :

A

the iron core of the transformer

B

the vibration of the primary coil

C

a varying induced electric field

a varying induced magnetic field

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Q 12. A boy is suffering from fever and doctor said that his body temperature is 105. Then temperature should be expressed in :

A

0C

0F

C

K

D

all of these

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Q 13. A manufacture marks the thermometer wrongly. At 00 C it reads - 100 C, at 1000 C it reads 850 C. Then the reading at 500C will be :

A

400C

B

32.50C

37.50C

D

42.50C

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Q 14. A graph was plotted between temperature is 0C (taking along x-axis) and temperature in Kelvin (along-y-axis), then which of the curve most correctly represent this behavior :

B

C

D

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Q 15. A student performs an experiment on ice of 1500 gm at 00C and wants to convert in into water at 00C. The quantity of heat required for the above experiment will be (L - Latent heat of fusion of ice):

1500 L

B

1.5 L

C

150 L

D

0.15 L

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Q 16. The surface of water in a lake is just going to freeze. What is the temperature of water at the bottom and at upper surface respectively :

40C, 00C

B

less than 00C, 00C

C

00C, 00C

D

more than 40C, 00C

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Q 17. Normal temperature of human body is nearly :

A

300C

370C

C

350C

D

450C

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Q 18. Mercury is used a thermometric liquid because :

A

If has low boiling point (B.P.) and high melting point (M.P.)

It has high B.P. and low M.P.

C

It has low B.P. and low M.P.

D

It has high B.P. and high M.P.

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Q 19. The value of 50C in 0F and K scale will be respectively :

A

41, 279

B

278, 41

41, 278

D

-23, 278

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Q 20. At dew point, relative humidity (RH) is :

A

10%

B

20%

C

50%

100%

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Q 21. A temperature difference of 300C in the Fahrenheit scale is :

540F

B

270F

C

860F

D

-540F

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Q 22. Which is correct statement _

1 K rise is equal to 10C rise

B

1 K rise is equal to 2730C rise

C

1 K fall is equal to 2730C rise

D

1 K rise is equal to 1000 C rise

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Q 23. Which graph represents correct curve between 0C along y-axis and 0F along x-axis :

A

B

C

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Q 24. Two blocks of iron A and B, A being four times heavier than B, are at 450C. The ratio of heat content of A and B is :

1 : 1

B

4 : 1

C

2 : 1

D

1 : 4

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Q 25. Bunty thought that if he mixed 440 gm of ice at 00C with 540 gm of water at 800C. Then what would remain after sometime :

A

only ice

only water

C

ice and water in same amount

D

ice and water will vapourise