XI physics guess paper : SECTION # B Attempt any TEN questions from this section. All questions carry equal marks. 1. Show that, (i) A . B = B. A. (ii) A X B = -B X A 2. Find the value of p for which the following vectors are perpendicular to each other. A = i - p j +3 k and B = 3i + 3j – 4k. 3. Define linear momentum. Give its unit M.K.S. system. State and prove the law of conservation of linear momentum. 4. A motor car is moving up a slope of 30 with a velocity of 72 km/hr, suddenly the engine fail. How much distance will the car move before coming to rest? Assume friction to the negligible. 5. A rocket is fired at a ground level target 600 m away with an initial velocity 85 m/s; find two possible values of launch angle. Calculate the minimum time to hit the target. 6. State and explain the law of conservation of angular momentum for a particle. 7. A uniform ladder of length “l” and weight 60 N rest against a smooth vertical wall. If the coefficient of friction between the ladder and the ground is 0.40, find the minimum angle such that the ladder may not slip. 8. Discuss the variation of g with altitude. 9. Define conservative Field. Prove that the gravitational field is a conservative field. 10. A note of frequency 500 Hz is being emitted by an ambulance moving towards a listener at rest. If the listener detects a frequency of 526Hz. Calculate the speed of the ambulance. Take the speed of sound at room temperature is 340m/s. 11. If the radius of the 14th Newton’s ring is 1mm, when light of wavelength 5.89 x 10-7 m is used. What is the radius of curvature of the lower surface of the lens used? 12. A diffraction grating with 1000 lines per centimeters is illuminated by yellow light of wavelength 589nm. At what angles are the 1st and 2nd order bright fringes seen? 13. A sound wave of frequency 500 Hz in air enters from a region of temperature 25 oC to a region of temperature 5 oC. Calculate the percent fractional change in wavelength. 14. Prove that the maximum range is 1/3 times the maximum height. 15. Determine the value of g at the center of earth. SECTION # C Attempt any TWO questions from this section. All questions carry equal marks. 1. (a) A particle is moving with a uniform speed along the circumference of a circle show that the motion of its projection along one of its diameter is simple harmonic motion. (b) What is diffraction of light and what is diffraction grating? Derive an expression for the wavelength of light by diffraction grating. 2. (a) Describe Newton’s formula for the speed of sound in a medium. What correction did Laplace make and on what assumption. (b) Draw a labeled diagram showing the passage of light rays through an astronomical telescope focused for infinity and obtain an expression for its magnifying power. 3. (a) Two bodies having different masses and moving with different velocities have an elastic collision in one dimension. Calculate the final velocities after collision. What will happen if the masses of the two bodies are equal? The masses of the two bodies are equal and one of them is initially at rest? (b) Define centripetal Force. Prove that centripetal acceleration is: v2 / r.
Posted on: Fri, 11 Apr 2014 06:40:36 +0000
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