Monday, 26 November 2018

Physics Class 11 Half Yearly Paper

Spectrum Classes by Er.Shyam Pachori CL 157 D.D Nagar Mob.:-9039803981

Time: 3 Hours               Max marks 70
General Instructions:
a) All the questions are compulsory.
b) There are 26 questions in total.
c) Questions to are very short answer type questions and carry one mark each.
d) Questions to 12 carry two marks each.
e) Questions 13 to 23 carry three marks each.
f)  Questions 24 to 26 carry five marks each.
g) There is no overall choice. However, an internal choice has been provided in one question of two marks, one question of three marks and all three questions in five marks each. You have to attempt only one of the choices in such questions.

Q1. Define standard international definition of 1 ampere .
Q2. What is the advantage of banking of road ?
Q3. Can a physical quantity have units but still be dimensionless ?
Q4.A truck and a car both are moving with same speed , Which has greater inertia ?
Q5.Define spring factor .
Q6.Explain type of friction with graph .
Q7.The kinetic energy of the body is increased by 69 % . What is the percentage increase in the linear momentum of the body ?
Q8. A lighter body and a heavy body both has same momentum , which has greater kinetic energy.
Q9. When the planet Jupiter is at a distance of 824.7 million kilometers from the Earth, its angular diameter is measured to be 35.72” of arc. Calculate the diameter of Jupiter.
Q10. A wire has a mass , radius  and length . The maximum percentage error in the measurement of its density
OR
A shell of mass 0.020 kg is fired by a gun of mass 100 kg. If the muzzle speed of the shell is 80 m s-1, what is the recoil speed of the gun ?
                                                                
Q.11 Prove that the angle of repose =  angle of friction .
Q12. Consider a simple pendulum, having a bob attached to astring, that oscillates under the action of the force of gravity. Suppose that the period of oscillation of the simple pendulumdepends on its length (L), mass of the bob(m) and acceleration due to gravity (g).
Derive the expression for its time period using method of dimensions.
Q13. State and Prove impulse momentum theorem by Calculus method.
Q14. A turn of radius 30 m is banked for the vehicles going at a speed of 54 km/h . If the coefficient of static friction between road and tyre is  0.5 , what is the max possible speeds of a vehicle so that it neither slip nor skids up ? ( g = 10 m/s2) 
Q15. A ball is dropped from a height of 90 m on a floor. At each collision with the floor,
the ball loses one tenth of its speed. Plot the speed-time graph of its motion between t = 0 to 12 s.
OR
Rain is falling vertically with a speed of 35 m/s. A woman rides a bicycle with a speed of 12 m/s in east to west direction. What is the direction in which she should hold her umbrella ?

Q16. State and Prove Newton’s 2nd law of motion by calculus method & why it is called as real law of motion Explain.
Q17. State and prove parallelogram law’s of vector’s  addition .
Q18. Suggest a suitable physical situation for each of thefollowing graphs
Q19. Explain why
(a) a horse cannot pull a cart and run in empty space,
(b) passengers are thrown forward from their seats when a speeding bus stops suddenly,
(c) it is easier to pull a lawn mower than to push it,
(d) a cricketer moves his hands backwards while holding a catch.
Q20. What is the acceleration of the block and trolley system shown in a, if the coefficient of kinetic friction between the trolley and the surface is 0.04? What is the tension in the string? (Take g = 10 m s-2). Neglect the mass of the string.
                                                       


OR 

Q21. What do you mean by bending of cyclist and derive the expression for the angle of bending.
Q22. A fighter plane flying horizontally at an altitude of 1.5 km with speed 720 km/h passes directly overhead an anti-aircraft gun. At what angle from the vertical should the gun be fired for the shell with muzzle speed 600 m/s to hit the plane ? At what minimum altitude should the pilot fly the plane to avoid being hit ? (Take = 10 m s-2 ).
Q23. State and prove work energy theorem by calculus method .
Q24.Explain Elevator problem with free body diagramA monkey of mass 40 kg climbs on a rope which can stand a maximum tension of 600 N. In which of the following cases will the rope break: the monkey
(a) climbs up with an acceleration of 6 m s-2
(b) climbs down with an acceleration of 4 m s-2
(c) climbs up with a uniform speed of 5 m s-1
(d) falls down the rope nearly freely under gravity?
(Ignore the mass of the rope).
OR
Define elastic collision. Prove that bodies of identical masses exchange their velocities after head on collision.
Q25. (a) State and prove law of conservation of mechanical energy .
(b) A man can swim with a speed of 4.0 km/h in still water. How long does he take to cross a river 1.0 km wide if the river flows steadily at 3.0 km/h and he makes his strokes normal to the river current? How far down the river does he go when he reaches the other bank ?
OR
(a) Define centripetal acceleration and derive its expression .
(b) The rear side of a truck is open and a box of 40 kg mass is placed 5 m away from the open end as shown in Fig. The coefficient of friction between the box and the surface below it is 0.15. On a straight road, the truck starts from rest and accelerates with 2 m s-2. At what distance from the starting point does the box fall off the truck? (Ignore the size of the box).
                                                             
Q26. (a) Define trajectory and prove that a horizontal projectile form parabolic path .
(b) A bullet fired at an angle of 30° with the horizontal hits the ground 3.0 km away. By adjusting its angle of projection, can one hope to hit a target 5.0 km away ? Assume the muzzle speed to the fixed, and neglect air resistance.
OR 
(a) Show that for a projectile the angle between the velocity and the x-axis as a function of time is given by                                     
                                                                                                                                                                                                                                                                                    
(b) Shows that the projection angle θ0 for a projectile launched from the origin is given by
                                             where the symbols have their usual meaning.