CBSE Board Class 11 Physics Previous Year Question Papers 2011

Previous Paper – 2011
Class – XI
Subject – Physics
Time : 1:30 hr          MM : 60
I.Answer the following questions: (1 Marks each)
a)What are the fundamental forces of physics?
b)What do you mean by inertia?
c)Calculate the angle of 1’ and 1’’.
d)1 fermi = _____m                                                                                                                                        
   1Aº = _____m                                                   1 astronomical unit  = _____m                       1 light year = _____m
e)What are strong and weak nuclear forces?
f)What is the difference between distance and displacement?
g)What do you mean by relative velocity?
h)State for each of the following physical quantities , if it scalar or a vector:                                        
volume, mass, speed, acceleration, density, angular frequency, displacement, number of moles.
i)What do you mean by instantaneous velocity?
j)State Newton’s first law of motion.

II.Answer the following questions: ( 2 marks each)
a)What is parallax? How can we use the parallax method to find infinite distance?
b)The moon is observed from tw diametrically opposite points A and B on the earth.The angle ᶿ  subtended at the moon by the two directions of observation is 1º54’. Given the diameter of the earth to be about 1.276X10⁶m. Compute the distance of the moon from the earth.
c)Derive a relation for the force acting on a particle of mass ‘m’moving with velocity ‘v’ in a circle of radius ‘r’.
d)Write the dimensional equation of acceleration, momentum, force and Kinetic Energy.
e)A cricket ball is thrownat a speed of 28m/sec.Calculate a) the maximum height   b)the time taken by the ball to return to the same level   c)the distance from the thrower to the point where the ball returns to the same level.


III.Answer the following questions: ( any five - 3 marks each)
a)A ball is thrown vertically upwards with a velocity of 20 m/sec from the top of a multistory building.The height of the point from where the ball is thrown is 25m from the ground.  a) how high will the ball rise?  b) How long will it be before the ball hits the ground?
b)A man walks on a straight road from his home to the market 2.5 km away with a speed of 5km/hr.Finding the market closed,he instantly turns and walks back home with a speed of 7.5 km/hr. What is the a) magnitude of average velocity  and  b) average speed of the man over the interval of time (i) 0 to 30 min , (ii) 0 to 50 min,  (iii) 0 to 40 min
c)A particle starts from the orogin at t=0sec with a velocity of 10j m/sec and moves in the x-y plane with a constant acceleration of (8i + 2j) m/sec².
(a) At what time is the x- coordinate of the particle 16m? What is the y-coordinate of the particle at that time?
(b)what is the speed of the particle at the time?
d)In a harbour,wind is blowing at the speed of 72 km/hr and the flag on the mast of the boat anchored in the harbour flutters along the N-E direction.If the boat starts moving at a speed of 51km/hr to the north,what is the direction of the flag on the mast of the boat?
e)State and derive newton’s second law of motion.
f)A constant force acting on a body of mass 3kg changes its speed  from 2 m/sec to 3.5 m/sec in 25sec.The direction of the motion of the body remains unchanged.What is the magnitude and direction of the force?

IV.Answer the following questions: ( any five - 5 marks each)
a)(i) What is projectile motion?                                                                                                                 
(ii) A hiker stands on the edge of a cliff 490m above the ground and throws a stone horizontally with an initial speed of 15m/sec.Neglecying air resistance find the time taken by the stone to reach the ground, and the speed with which it hits the ground.
b)(i) Find the magnitude and direction of the resultant of two vectors A and B in terms of their magnitude and angle ᶿ between them.                                                                                                                  
  (ii) Define law of sines and law of cosines.
(i)What do you mean by static friction?                                                                                                 
(ii) In the figure1.1 , A mass of 4 kg rests on a horizontal plane. The plane is gradually inclined until at an angle ᶿ= 15⁰ with the horizontal , the mass just begins to slide. What is the coefficient of static friction between the block and the surface?
                                                                                                                                                                                            
d)A body of mass 0.40kg moving initially with a constant speed of 10m/sec to the north is subject to a constant  force of 8 N directed towards the south for 30 sec. Take the instant the force is applied to be t=0, the position of the body at that time to be x=0, and predict its position at  t= -5sec, 25 sec,100 sec.
e)  Derive kinematics equation for uniformly accelerated motion.