Physics Class XI Sample Paper 1, set 2
Time: 3 hr
Maximum Marks: 70
Date: September 2024
Section A: 1 mark questions
- The dimensional formula of force is
- (a) [M1L1T-2]
- (b) [M0L0T2]
- (c) [M'L2T-2]
- (d) [M'L T']
- The number of significant figures in 20340 is
- (a) 3
- (b) 4
- (c) 5
- (d) none of these
- Name the physical quantity which has a unit but no dimension.
- (a) strain
- (b) frequency
- (c) angular displacement
- (d) radius
- When a vector A is multiplied by a negative number –λ
- (a) Its magnitude becomes λ times, direction remains same as A.
- (b) Its magnitude becomes λ times, direction becomes opposite to A.
- (c) Its magnitude remains same and direction also remains same as A.
- (d) Its magnitude remains same, direction becomes opposite to A.
- Area under velocity-time graph tells us the
- (a) Time
- (b) Acceleration
- (c) Displacement
- (d) Velocity
- Centripetal acceleration always acts
- (a) Along the radius towards the centre of circular path
- (b) Along the tangent
- (c) Along the radius away from the centre of circular path
- (d) Perpendicular to the plane of circular path
- The working of rocket is based on the principle of
- (a) Newton's first law
- (b) Inertia of rest
- (c) Conservation of linear momentum
- (d) None of these
- Maximum force of friction is called
- (a) Static friction
- (b) Limiting friction
- (c) Dynamic friction
- (d) Sliding friction
- Direction of linear velocity vector in circular motion is along
- (a) Tangent to circular path
- (b) Inward radius
- (c) Outward radius
- (d) Axis of rotation
- A person is sitting on the open door of a moving bus without holding it. When the bus takes a sharp turn, the person falls outside on the road. This happened due to
- (a) Inertia of rest
- (b) Inertia of motion
- (c) Inertia of direction
- (d) All of these
- According to work energy theorem, work done by the net force on a particle is equal to change in its
- (a) Linear Momentum
- (b) Angular Momentum
- (c) Velocity
- (d) Kinetic Energy
- Which one of the following is a non-conservative force?
- (a) Gravitational force
- (b) Electrostatic force
- (c) Magnetic force
- (d) Force of friction
- Analogue of mass in rotational motion is
- (a) Moment of inertia
- (b) Angular Momentum
- (c) Torque
- (d) None of these
- A circular disc has mass M and radius R. Moment of inertia about its diameter will be
- (a) 2/5MR²
- (b) 1/4 MR²
- (c) 1/2 MR²
- (d) MR²
- When a mass M is rotating in a plane about a fixed point O, its angular momentum L is directed along
- (a) A line perpendicular to the plane of rotation
- (b) The radius
- (c) The tangent to the orbit
- (d) None of these
- If x = a + bt + ct², where x is in metres and t in seconds, then what is the unit of ‘c’?
- (a) m/s
- (b) m/s²
- (c) kgm/s
- (d) m²/s
- What is the ratio of the average acceleration during the intervals OA and AB in the velocity-time graph?
- (a) 1/2
- (b) 1/3
- (c) 1
- (d) 3
- A solid cylinder has mass 2 Kg and radius 5 cm. Moment of inertia about its axis will be
- (a) 10 Kgcm²
- (b) 25 Kgcm²
- (c) 25 Kgm²
- (d) 50 Kgcm²
- A constant force acts on a body of mass 5 kg and changes its speed from 5 m/s to 10 m/s in 10 seconds, without changing the direction of motion. The force acting on the body is
- (a) 1.5 N
- (b) 2N
- (c) 2.5 N
- (d) 5 N
- One end of a string of length l is connected to a particle of mass m and the other to a small peg on a smooth horizontal table. If the particle moves in a circle with speed v, the net force on the particle is (T is tension in the string)
- (a) T
- (b) T - mv²/l
- (c) T + mv²/l
- (d) 0
Section B: 2 mark questions
- Write the dimensional formulas of the following quantities:
- (a) linear momentum
- (b) strain
- (c) torque
- (d) surface tension
Convert 1 Newton into dyne using dimensional analysis.
- Define light year and astronomical unit.
OR
- Check whether the following equation is dimensionally correct: ½ mv² = mgh
- Why does a gun recoil when a bullet is fired? Write the necessary formula.
OR
Define (i) Static friction, (ii) Limiting friction, and (iii) Kinetic friction. Draw graphs of these versus applied force. Also explain why kinetic friction is smaller than limiting friction.
- Static friction is a self-adjusting force of friction. Explain.
- State 4 laws of limiting friction. Or Why is friction called a necessary evil? Write at least 2 points in favor and 2 against the friction.
- Prove that the mechanical energy (KE + PE) of a freely falling body always remains constant. Or A 1 kW motor is used to pump water from a well 10 m deep. Calculate the quantity of water pumped out per second.
- What is work-energy principle? Write an expression (without derivation) for it. OR The linear momentum of a body is increased by 10%. What is the percentage change in its KE?
Section C: 3 mark questions
- Write at least 3 differences between speed and velocity. OR A player throws a ball upwards with an initial speed of 29.4 ms-2. To what height does the ball rise and after how long does the ball return to the player’s hands? (Take g = 9.8 ms-2 and neglect air resistance)
- Show that in uniformly accelerated motion in one dimension:
- (i) Acceleration is equal to the slope of the velocity-time graph.
- (ii) Displacement is equal to the area under the velocity-time graph.
- Prove that Newton’s 2nd law is the real law of motion. OR A body weighing 0.4 kg is whirled in a vertical circle making 2 rps. If the radius of the circle is 1.2 m, find the tension in the string at (i) top of the circle, and (ii) bottom of the circle.
- Prove that in the elastic collision of two bodies in one dimension, the value of the coefficient of restitution is e = 1. Also, find expressions of velocities of two bodies after the collision.
- Find the position vector for the center of mass (CM) of a two-particle system. OR Define the radius of gyration of a body and derive its expression.
- What do you mean by angular momentum? What is the geometrical meaning of the angular momentum of a particle? OR Prove that if the external force acting on a system is zero, then the center of mass moves with a constant velocity. Also explain: (i) Disintegration of a nucleus (ii) Motion of a double star system on the basis of the center of mass motion.
- Derive the relation of kinetic energy in rotation. OR
Section D: Comprehension type question
16. The rotating action of a force is called torque. It is defined as the product of force and the perpendicular distance of force from the axis of rotation. It is denoted by τ = F x d. Its units are Nm, and its dimensions are [ML²T⁻²].
- (a) What is the rotating action of a force called?
- (b) What is the formula of torque in polar coordinate form?
- (c) What are the units of torque?
- (d) In rotational motion, work is equal to the product of _________ and _________.
- (e) What is the corresponding quantity of torque in translational motion?
Section E: 5 mark questions
- Derive the relations:
- (i) v = u + at
- (ii) S = ut + ½ at²
- (iii) v² – u² = 2aS
- OR State the parallelogram law of vector addition. Find the magnitude and direction of the resultant vector using analytical treatment. Also, discuss the case when the angle between two vectors A and B is 90°.
- Find the expression of the distance covered by a body in the nth second of its motion. Discuss the case when the body falls freely under gravity with an initial velocity of zero. OR Define projectile motion. Find expressions for: (i) Time of flight (ii) Horizontal range of a projectile given angular projection.
Answer Key
- (i) A
- (ii) B
- (iii) C
- (iv) B
- (v) C
- (vi) A
- (vii) C
- (viii) B
- (ix) A
- (x) C
- (xi) D
- (xii) D
- (xiii) A
- (xiv) B
- (xv) A
- (xvi) B
- (xvii) B
- (xviii) B
- (xix) C
- (xx) A
