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Important Questions

CBSE Guess > Papers > Important Questions > Class XII > 2009 > Science > Science By Vivek Soni

CBSE CLASS XII

Section - A (Physics)

Q. 1. Derive the first equation of motion graphically. [2]

Q. 2. “Still friction is essential , although it is useful in many ways.” Comment. [2]

Q. 3. A train is traveling at a speed of 50 Km/hr. Breaks are applied so as to produce the uniform acceleration of - 0.5 m/s2. Find how far the train will go before it is brought to rest. [2]

Q. 4. An object of mass 1 Kg traveling in a straight line with a velocity of 10 m/s collides with and sticks to a stationary wooden block of mass 5 Kg.Then they both move off together in the same straight line.Calculate the total momentum Just before and after the impact.Also calculate the velocity of the combined object. [3]

Q. 5. (a) What can you say about the motion of an object whose distance time graph is parallel to time axis ?

(b) How will you calculate the distance traveled by an object with the help of speed time graph. [3]

Q. 6. Differentiate between speed and velocity . [3]

Q. 7. Give the answer of following in one word or in one sentence : - [5]

  1. Give one example of retardation.
  2. Under which condition velocity varies with time but the velocity of an object during any time interval is not zero.
  3. What is inertia ?
  4. State one method used to reduce the friction between two surface.
  5. Define the S.I unit of force.

Or

Prove that total momentum of an object before and after the collision remains the same.

Section - B (Chemistry)

Q. 8. Give four examples of a substance which are sublime in nature. [2]

Q. 9. Why is the rate of diffusion in liquid is higher then that of solid ? [2]

Q. 10. Why is the solid Carbondioxide also known as Dry ice ? [2]

Q. 11. Give examples of following types of collides : [3]

  1. Liquid into gas.
  2. Solid into liquid.
  3. Gas into solid.

Q. 12. What is chromatography ? Hence describe an activity to show it ? [3]

Q. 13. Give reasons for the following : [3]

  1. Ice at 273 K is more effective in cooling than water at same temperature.
  2. A desert cooler cools better on a hot dry day.

Q. 14. List out the difference between three states of matter. [5]

Or

Differentiate between Solution, Suspension and Colloidal Solution.

SECTION – C (Biology)

Q. 15. Who coined the term cell and when? [1]

Q. 16. What is Plasmolysis ? [1]

Q. 17. What is diffusion. Explain how it is useful for living beings. [3]

Or

Give reasons for the following :

  1. Mitochondria is known as powerhouse of cell.
  2. Lysosomes are also known as suicide bags.

Q. 18. Using appropriate diagram, list out the difference between plant cell and the animal cell.

Or

What is a plasma membrane? Write its main feature? Why is plasma membrane called a selectively permeable membrane? [5]

Paper By Vivek Soni