Subject : Physics (Subjective)
Class - IX
Time : 2 hours. Marks. 40
[N.B : Answer any five question from group A and Answer any five from group B ]
Group : A
1. What is venire constant ? What is Back lash error ? 1+1 = 2
2. What is force ? State the low of conservation of momentum. 1+1 = 2
3. Define hydro electricity. What is the meaning of 60 w-electric bulb ? 1+1 = 2
4. Define solid angle. What do you mean by 1 candela ? 1+1 = 2
5. What is Regulation ? What do you mean by Otto cycle ? 1+1 = 2
6. What do you mean by desired unit ? What do you understand inertia ? 1+1 = 2
7. Define watt ? What do you mean by Thrust ? 1+1 = 2
8. What is phase ? What is Echo ?
9. What is Friesian ? Find out the unit of thermal conductivity. 1+1 = 2
10. State coulomb is law. 2
Group : B
11. Describe with diagrams in detail the domain theory of magnetism. 6
12. a) What is an electroscope ? Describe how with the help of this instrument the nature of charge is detected.
b) In air a charge of 30 coulombs and 50 coulombs are at a distance of I'm from each other. Find the unsent of force between them. 4+2 = 6
13. a) Describe searle's method for determining the thermal conductivity of metals.
b) Temperatures of two sides of a brass plate of thickness 4 m m are 10oc and 300c respectively. 33 KJ amount of heat flows per second through this plate. If thermal conductivity of brass is 110 w m-1 k -1 then find the area of the plate. 4+2 = 6
14. a) State and explain the law of a simple pendulum. 4+2 = 6
b) A simple pendulum Oscillates 30 times in a minute. Find the effective length of the pendulum 9.8 ms -2.
15. a) From Newton's second law of motion, Prove the F = ma.
b) A bullet of mass 10 gm leaves the barrel of a gun of mass 6 kg at the velocity of 300 ms -1.Determine the backward velocity of the gun. 4+2 = 6
16. a) Describe a method for determining the specific heat of solid.
b) Find the amount of heat required to convert 100 gm ice at -10oc to water at 1000c. Specific heat of ice. melting point of ice and specific latent heat of fusion of ice are 2100 J Kg-1k-1,ooc and 336000 JKg-1 K-1 -1 respectively. 4+2 = 6
17. a) Deduce the relation between real expansion and apparent expansion of a liquid.
b) What is the difference between heat and temperature ? 4+2 = 6
18. a) Describe the mechanism for propagation of sound in air.
b) What is sound pollution ?
19. a) Explains the working principal of a Hydraulic press with a neat diagram.
b) The sp. gr. of a body is 6 and weights 36 N in air. What is its weight in water ? 4+2 = 6
20. a) Prove the principle of conservation of energy in case of a freely falling body under the action of gravity.
b) A boy of mass 35 kg can rise 20 steps each step being 20 cm high in a time of 5 see. What is his power ? 4+2 = 6
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