Second term exam Answer key - Physics standard 9

Second Term Exam-2013 Standard 9 Physics

Answer key

1. Power (1)
2. The rays of light incident on the lens are parallel (1)
3. Potential Energy → Kinetic Energy → Electric Energy → Heat Energy (2)
4. A = 60W B = 2250 J (2)
5. a. Medium A (1)
   b. Medium B (1)
   c. It will be in straight line (1)
6. Frequency – number of vibrations per second – Hertz
   Rate of change of momentum – Second law of motion – kgm/s²
   action and reaction are equal and opposite – Third law of motion – rocket (3)
7. a. Force and displacement (1)
   b. W= mgh = 12 x 10 x 5 = 600 J (2)
8. a. The vertical line from the centre of gravity is out side the base. (1)
   b. 4 (1)
   c. The point c become lower (1)
9. a. The falling due to the gravitational attraction of earth only. (1)
   b. zero (1)
   c. Both spheres will reach at the same time (1)
10. a. F = GMm/R² (1)
    b. F = ma (1)
    c. a = GM/R² (1)
11. a. Potential Energy (1)
    b. the stone due to position and spring due to strain (1)
    c. Total Energy = U = 2 x10 x 5 = 100 J (1)
    It get Kinetic Energy of 100J, when just before it touches the ground (1)
12. a. A (1)
    b. zero (1)
    c. mass at A and B are same. Weight is more at A. (2)
13. a. because the angle of incidence is greater than critical angle. (1)
    b. Total internal reflection (1)
    c. Refraction is taken place here.
    The angle of incidence is less than critical angle. (2)
14. (A)a. u = -6cm, v = +3cm (1)
    b. yes (1)
    c. 2 cm (1)
    f = uv/u-v = -6 x 3 /-6 -3 = -18 / -9 = 2 cm (1)
    OR
15. (B) a. Draw the Image formation (2)
    b. virtual, erect, small (1)
    c. Between F and O (1) 
    
    
    Standard 9 Answer key