Sample Paper – 2009
Class – XI
Subject – Physics

MAX MARKS-70 TIME-3hrs.

General Instructions
1. All questions are compulsory. Symbols have their usual meaning.
2. Q.No. 1 to 8 are of very short answer type questions, carrying 1 mark each.
3. Q.No.9 to 18 are of short answer type questions, carrying 2 marks each.
4. Q. No. 19 to 27 carry 3 marks each.
5. Q. No. 28 to 30 carry 5 marks each.
6. Use of calculator is not permitted. However you may use log table, if required.
7. Draw neat labelled diagram wherever necessary to explain your answer.


1. Write down the unit and dimension of surface energy.
2. Is it true that the instantaneous velocity of a projectile is tangential to its parabolic path?
3. What type of friction is involved when an axle rotates in a sleeve?
4. Can we get off a frictionless horizontal surface by jumping?
5. Is work done by a non- conservative force always negative? Comment.
6. Can centre of mass of a body coincides with geometrical centre of the body?
7. Two simple pendulums of unequal length meet each other at mean position. What is their phase difference?
8. Is the phenomenon of beats observable incase of two light waves of nearly equal frequencies?
9. Write the dimensions of a and b in the formula v=a+bt, where v is velocity and t is time.
10. A body travels with velocity v1 for time t1 secs and with velocity v2 for time t2 secs in the same direction. Find the average velocity of the body.
11. A ball is dropped from a height of 90m on a floor. At each collision with the floor, the ball looses one tenth of its speed. Plot the speed-time graph of its motion between t=0 to 12 secs. (g=10m/s2)
12. State triangle law of vector addition. Find out the angle between the resultant vector and the vector A when two vectors A =3m is acting towards east and vector B=4m is acting towards the north east.
Or
The driver of a truck traveling with a velocity V suddenly notices a brick wall in front of him at a distance d. It is better for him to apply brakes or to make a circular turn with out applying brakes in order to just avoid crashing into the wall. Why?
13. Prove work-energy theorem for a variable force.
14. The moments of inertia of two rotating bodies A and B are IA and IB (IA > IB) and their angular momenta are equal. Which one has greater kinetic energy?
15. A satellite orbits the earth the earth at a height of 400Km above the surface. How much energy must be expanded to rocket the satellite out the gravitational influence of earth? Mass of the satellite is 200Kg, mass of the earth = 6.0x 106m, G=6.67 x 10-11 Nm2/Kg2.
16. Why is spring made of steel not of copper?
17. A refrigerator is to maintain eatables kept inside at 90C, if room temp is 360C. calculate the coefficient of performance.
18. The volume of vessel A is twice the volume of another vessel B and both of them are filled with the same gas. If the gas in A is at twice the temperature and twice the pressure in comparison to the gas in B, what is the ratio of gas molecules in A and B?
19. A projectile is fired with a velocity V, at an angle ? with the ground. Derive equations for (i) time of flight and (ii) maximum height attained by the projectile.
20. State and explain Newton’s laws of motion. Why it is called the real law of motion.
21. Obtain an equation for the final velocities of the bodies A and B after an elastic collision when B is at rest and A is moving with a velocity V1i.
22. Deduce an expression for the acceleration due to gravity at a depth ‘d’ from the surface of earth.
23. A hole is drilled in a copper sheet. The diameter of the hole is 4.24 cm at 27.00C. What is the change I the diameter of the hole when the sheet is heated to 2270C? Coefficient of linear expansion of copper = 1.70 x 10- 5 0C.
24. Derive an equation for the work done in an isothermal process and draw the P-V indicator diagram.
25. An oxygen cylinder of volume 30 litres has an initial gauge pressure of 15 atm and a temperature of 270C. After some oxygen is with drawn from the cylinder, the gauge pressure drops to 11 atm, and its temperature drops to 170C. Estimate the mass of oxygen taken out of the cylinder. ( R=8.1 J/mol K, molecular mass of O2= 32u)
26. Define centre of mass. Deduce an expression for the position of centre of mass of an N-particle system. Does the centre of mass a rigid body vary ?
27. Deduce an expression for the total energy of a system executing S.H.M. Draw the energy curve.
Or
What do you mean by standing wave? Deduce an expression for the nodes and antinodes of a standing wave. Write down the positions of nodes and antinodes.
28. Why are the wheels circular? Deduce an expression for the maximum velocity with which a vehicle can move in a banked circular track.
Or
Friction is a necessary evil, comment. Mention some methods of reducing friction.
29. What is an ideal liquid? Derive an equation for the height of the liquid rise in a capillary tube.
Or
State Bernoulli’s principle. Deduce an expression for the volume of the liquid flowing per second through the wider tube of a venture meter.
30. What do mean by damped oscillation? Deduce an expression for the displacement, angular frequency and energy for damped simple harmonic oscillations.
Or
Explain Doppler’s effect of sound. Obtain an expression for apparent frequency of sound when source and observer are approaching each other .