A Random Collection of Sample Questions for Class XI
1 MARK Questions
- What is the ratio of the S.I. to the c.g.s. units of work?
- What is the ratio of the K.E. of the body at the bottom to the K.E. at the top, while it is describing a vertical circle of radius ‘r’?
- On earth the value of G is 6.673 ´ 10-11Nm2kg-2. What is its value on moon where ‘g’ is nearly six times smaller than that on earth?
- Define Force constant and give its dimensional formula.
- What are infrasonic waves?
2 MARKS Questions
- Force (F) and density(d) are related as , where a and b are dimensional constants. Write the dimensional formula for a and b.
- A body is moving with a uniform acceleration of 10ms-2. If it starts moving from rest, calculate its displacement after 5 seconds.
- “A cricket player lowers his hands to catch the ball safely.” Explain why.
- Explain the need of banking of tracks.
- Can a centripetal force do a work on the rotating body? Explain your answer.
- Derive relation between torque and angular momentum.
- State Kepler’s second and third laws of planetary motion.
- Explain why a gas has two specific heats?
- At what distance from the mean position in S.H.M., the energy is half kinetic and half potential?
- What is Doppler’s effect? Derive expression for the apparent frequency when sound is in motion and listener is at rest.
3 MARKS Questions
- Define Dimensional formula. Give uses of Dimensional analysis.
- A projectile is thrown parallel to the horizontal. What is the velocity and the angle which the projectile will make with the horizontal after time ‘t’.
- Prove that Newton’s second law is the real law of motion.
- Distinguish between conservative and non-conservative forces. Show that gravitational force is a conservative force.
- The momentum of a body increases by 20%. What is the percentage increase in kinetic energy?
- What will be the duration of the day, if earth contracts to the of its original volume, mass remaining constant?
- If radius of earth were increased by a factor of 3, by what factor would its density have to be changed to keep the value of ‘g’ same.
- Calculate the energy spent in spraying a drop of mercury of 1cm radius into 106 droplets, all of same size. Surface tension of mercury is 55´10-2 Nm-1.
- A Carnot engine operates between 500k and 400k. If it absorbs 6´105 cal heat at higher temperature, how much work per cycle can the engine perform?
- Derive an expression for total energy of a particle executing S.H.M.
- Show that the ratio of frequencies of first three harmonics in open end organ pipe is 1: 2 : 3.
5 MARKS Questions
- Derive a relation for the distance covered in nth by a uniformly accelerated body. A body is moving with a uniform acceleration. Its velocity after 5 seconds is 25 m/s and after 8 seconds is 34 m/s. Calculate the distance it will cover in the 10th second.
- State and prove Bernoulli’s theorem for a non-viscous liquid.
- From kinetic theory of gas, find an expression for pressure exerted by gas on the walls of container.
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