FA-3 PHYSICAL SCIENCE CLASS 9

CLASS-09

MODEL PAPER - 1

FORMATIVE ASSESSMENT -3

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I. Choose the correct answer. 5x1 = 5M

1. Plum pudding model of atom was proposed by ……

A. Rutherford.      B. Bohr 

C. J.J.Thomson      D. Chadwick 

2. Number of neutrons present in 90Th230

A. 90.          B. 230

C. 320          D. 140 

3. Valency of Magnesium (Z = 12)

A. 0         B. 1

C. 2          D. 3

4. Hertz stands for oscillations per

A. second       B. minute

C. hour           D. millisecond

5. When we say sound travels in a medium

A. The medium travels B. The particles of the medium travels

C. The source travels D. The disturbance travels

II. Fill in the blanks. 5x1 = 5M

6. Maximum number of electrons that can be accommodated in L – shell is ……………….….

7. …….. isotope is used as fuel in Nuclear reactor. 

8. Sound can’t travel through ………………

9. If the frequency of sound wave is more than 20KHz, then the sound is called …………….

10. SONAR stands for ……………………………………………………………………………….

III. Answer the following questions. 3x2 = 6M

11. What is the main difference between isotopes of the same element?

12. Write any two differences between electron, proton and neutron. 

13. Name two quantities that vary periodically at a place in air as a sound wave travels through it.

IV. Answer the following question. 1x4 = 4M

14. (A) Give the main postulates of Bohr's model of an atom. 

(OR)

 (B) Define the wave length of a sound wave. How is it related to the frequency and the wave 

 speed ?