# HBSE Class 11 Physics Half Yearly Question Paper 2023 Answer Key

Haryana Board (HBSE) Class 11 Physics Half Yearly Question Paper 2023 Answer Key. Haryana Board Class 11th Half Yearly Question Paper Pdf Download 2023. Haryana Board Class 11th Half Yearly Question Paper Solution 2023. HBSE Class 11th Half Yearly Exam 2023. HBSE Physics Half Yearly Question Paper 2023 Answer Key.

HBSE Class 11 Physics Half Yearly Question Paper 2023 Answer Key

Instructions :
• All questions are compulsory.
• Questions (1-15) carry 1 mark each.
• Questions (16-18) carry 2 marks each.
• Questions (19-21) carry 3 marks each.
• Questions (22-23) carry 5 marks each.

1. The Gravitational constant has unit :
(a) Nm–2
(b) Nm2kg–2
(c) Nm2
(d) Nkg2

2. Which of the physical quantity is dimensionless variable :
(a) Viscosity
(b) Relative mass
(c) Electric current
(d) Surface tension

3. Dimensional formula for Energy is …………
(a) MLT
(b) ML2T–2
(c) MLT–3
(d) None of the above

4. Bounsing back of a ball is an example of :
(a) 1st law of motion
(b) 2nd law of motion
(c) Zeroth law
(d) 3rd law of motion
Answer – (d) 3rd law of motion

5. Which of the following is non-conservative :
(a) Gravitational force
(b) Frictional force
(c) Electrostatic
(d) None of the above

6. An object is moving with uniform velocity of 40 m/s. The instantaneous velocity of the object will be :
(a) 10 m/s
(b) 30 m/s
(c) 40 m/s
(d) 25 m/s

7. Which of the following is self-adjusting force?
(a) Kinetic friction
(b) Limiting friction
(c) Static friction
(d) All of these

8. SI unit of pressure is :
(a) Torque
(b) Pascal
(b) Bar
(d) None of these

9. Which law of motion is real law of motion :
(a) Newton’s 1st law of motion
(b) Newton’s 2nd law of motion
(c) Newton’s 3rd law of motion
(d) None of the above
Answer – (b) Newton’s 2nd law of motion

10. The position-time equation for the uniformly accelerated motion is :
(a) v = u + at
(b) s = ut + ½at2
(c) v2 – u2 = 2as
(d) None of the above
Answer – (b) s = ut + ½at2

11. The mathematical expression for the kinetic energy is …………

12. Commercial unit of power is …………

13. The resultant force acting on a body when the system is in equilibrium is …………

14. Maximum value of limiting friction is kinetic friction. (True / False)

15. Motion in Straight line is one dimensional motion. (True / False)

16. What are the fundamental and derived units?
Answer – The base unit of the measurements are known as the fundamental units. e.g. meter, kilogram etc.
The units expressed in terms of the fundamental units are known as the derived units. e.g. force, weight etc.

17. Derive: s = ut + ½at2
Answer – Let the initial velocity of a body is u and the final velocity of the body is v.
The average velocity of the body = (v+u)/2
Distance travelled = Average velocity × Time
s = (u+v)/2 × t ………(i)
Using the first equation of motion we can write,
v = u + at ……..(ii)
From eqn.(i) and (ii),
s = (u+u+at)/2 × t
s = (2u+at)/2 × t
s = ut + ½at2

18. Define torque. Relate it to force. Also mention its S.I. unit.
Answer – The turning effect of a force about the axis of rotation is called moment of force or torque due to the force. SI unit of torque is Nm.

19. Why it is difficult to push a lawn roller than to pull it?
Answer – In pushing frictional force is greater than that of in case of pulling. When you push you to add some normal of mg, so friction also increases but in case of pulling at the time you are pulling you decrease the normal so friction reduced and & it becomes easier.

20. Define :
(i) Time of flight
Answer – The time taken for the projectile to complete its trajectory or time taken by the projectile to hit the ground is called time of flight .

(ii) Maximum height
Answer – The maximum height of the object is the highest vertical distance from the horizontal plane along its trajectory.

(iii) Horizontal range
Answer – A projectile’s horizontal range is the distance along the horizontal plane. Moreover, it would travel before it reaches the same vertical position as it started from.

21. Relate torque and angular momentum. Also define centre of mass.
Answer – Relation between Torque & angular momentum is L = (τω)/α
The specific point of the body where all the mass of the body is supposed to be contained and the body moves such that all the external force act at this point, is known as the center of mass of the body.

22. Derive expression for potential energy of spring. Define force constant.
Answer – Spring potential energy = force × distance of displacement.
Also, the force is equal to the spring constant × displacement.
The Potential energy of a spring is :
P.E. = ½kx2
Here P.E. is potential energy of a spring, k is Spring constant and x is Spring displacement.
The force constant or spring constant is a measure of the stiffness of a spring. It is the force per unit deformation of the spring. Its SI unit is N/m.

OR

Disuss the elastic collision in one-dimension and derive the expression for the velocities of bodies after collision.