CBSE Class - XI Physics (Set 2) Last year Paper (2015-16)

Time: 3 Hrs. M.M: 70

General Instructions:

1. Question 1 to 5 one mark.
2. Question 6 to 10 each two mark.
3. Question 11 to 22 each three mark.
4. Question 23 is value based question and carry four marks.
5. Questions 24 to 26 each five mark.

Section A

Identify the term which has unit but no dimension.

Would you expect a typical trajectory of a ping-pong ball to be a parabola, why?

1. What property of a tennis determine the ease with which it can be rapidly rotated?
2. Define safety factor in elasticity
3. Can water be made to boil without heating?

Section B

1. Two principal thrusts in physics are unification and reduction. Justify by giving illustrations.
2. An aircraft executes a horizontal loop at a speed of 720 km/h with its wings banked at 15°. What is the radius of the loop?
3. Can a body have energy without having momentum and have momentum without energy? Explain.

9. Pressure of a gas in a closed cylinder is expressed in the following manner <math>p = p_n + h\rho g</math> Identify the expressions for

1. absolute pressure of the gas
2. gauge pressure of the gas
3. What do you mean by phase of a wave? How does it change with position?

<math>\mathbf{or}</math> 1/4

The frequencies of two tuning forks A and B are 250 Hz and 255 Hz, respectively. Both are sounded together. How many beats will be heard in 5s?

Section C

1. A particle of mass m is projected with velocity v at an angle <math>\theta</math> with the horizontal. Find its angular momentum about the point of projection when it is at the highest point of its trajectory.
2. Find the expression for variation of acceleration due to gravity g, with height above the surface of the earth.
3. A spring mass system is hanging from the ceiling of an elevator in equilibrium. The elevator suddenly starts accelerating upwards with acceleration a.

Find:

1. the frequency
2. the amplitude of the resulting SHM.
3. What is an isothermal process? Derive an expression for work done during an isothermal expansion of a gas.
4. What is capillarity? Water rises in a capillary tube to a height of 4.0 cm. In another capillary tube whose radius is one third of it, how much the water will rise?
5. Compute the fractional change in volume of a glass slab, when subjected to a hydraulic pressure of 10 atm.
6. Find the molar specific heat of the process <math>p = b</math> for a diatomic gas, b being constant.
7. Define centre of mass of a n particles system. State the coordinates of centre of mass of a n particles system.
8. Derive the expression for excess pressure inside a spherical liquid drop of radius R.

or The molecules of a given mass of a gas have root mean square speeds of 100 m/s at 27°C and 1.00 atm pressure. What will be the root mean square speeds of the molecules of the gas 2/4