## First Year Physics full book MCQs

## 1st Year Physics Guess Paper 2023 for Punjab Boards

ILM KI ROSHNI | GUESS PAPER | |||||

Class | 1^{st} YEAR | Subject | Physics | Total Marks | 17 | |

Roll No. | Date | Time Allowed | 20 Min |

**(Objective Type)**

**Note: ****Four possible answers A, B, C and D to each question are given. The choice**** ****which you think is correct, fill that circle in front of that question with Marker**** ****or Pen ink in the answer Book. Cutting or filling two or more circles will result ****in zero mark in that question. **

**Q.No.1**

**The time of 30 vibrations of in the time period of a vibrating body, the least count of the timing device is _________ number of vibrations.**

(A) 1.82±0.006 (B) 0.54±0.003 (C) 1.82±0.003^{ }(D) 0.54±0.006

**Which quantity has different dimension from others?**

(A) Tension (B) Work (C) Energy^{ }^{}(D) Torque

**Work done by the force**3i+2j**for a distance**4i+ 5j**will be :**

(A) 12 units (B) 22 units (C) 32 units^{} (D) 42 units

**The unit vector of the vector**A= 4i+3j**is given by :**- 7 (B) 3i+4j5 (C) 5
^{}(D) 3i+4j5 **A certain force gives an acceleration of**2 m/sec2**to a body of mass 5 Kg. the same force would give a 20 kg object an acceleration of :**

(A) 0.5 m/sec2 (B) 5 m/sec2 (C) 1.5 m/sec2 (D) 9.8 m/sec2

**Change in momentum per one second is called**

(A) Force (B) Impulse (C) Energy (D) Work

**Energy stored in the spring of a watch is called:**

(A) Potential energy (B) Kinetic energy (C) Nuclear energy (D) Elastic potential energy

**The whole circumference subtends at the centre of the circle angle of:**- 2π radians (B) π (C) 6 radius
^{}(D) None of these **Formula for calculate moment of inertia of the bodies of one pair is same. Tick the answer:**

(A) disc, solid cylinders (B) sphere, hoop (C) Thin rod, hoop (D) Hoop, disc

**When the droplet moves with terminal velocity in a fluid, the net force eating on the droplet is:**

(A) FD-mg (B) Zero (C) mg-FD^{} (D) None of these

- Sin (ωt +90)
**is equal to:**

(A) Sin ωt (B) cos ωt (C) – Sin ωt ^{} (D) None of these

**The component mg**cos θ**in simple pendulum balanced by?**

(A) mg sin θ (B) mg (C) Tension in the string (D) All of these

**The speed of waves in the string in terms of the tension F and mass per unit length (m) of the string is given by:**

(A) v= F×1m (B) v= Fm (C) v= mf^{ }^{}(D) v= Fm1

**Two degree Celsius rise in temperature of the medium, produce approximately increase in the speed of sound equal to:**

(A) 0.61 m/sec (B) 0.61 m/sec (C) 1.22 m/sec^{ }^{}(D) 0.61 mm/sec

**Which of the following cannot be polarized:**

(A) Ultraviolet rays (B) Sound waves (C) Radio waves (D) X-rays

**The axes of rotation of turntable and telescope (in the spectrometer):**

(A) Are perpendicular to each other (C) Are along the same line

(B) Make an angle of 450with each other (D) None of these

**What will be efficiency of a carnot engine when it is operated between the temperatures**470C**and**1270C

(A) 20% (B) 50% (C) 60%^{} (D) 75%

**Sections -I**

**Q.No.2**** ****Write short Answers to Any Eight (8) questions.**** **** ****(16)**

- Name several repetitive phenomenon occurring in nature which could serve as reasonable time standards.
- An old saying is that “A chain is only as strong as its weakest link”. What analogous statement can you make regarding experimental data used in a computation?
- Does a dimensional analysis give any information on constant of proportionality that may appear in an algebraic expression? Explain.
- The vector sum of three vectors gives a zero resultant. What can be the orientation of the vectors?
- Can a vector have a component greater than the vector’s magnitude?
- Can you add zero to a null vector?
- If one of the rectangular component of a vector is not zero, can its magnitude be zero? Explain.
- Can a body rotate about its centre of gravity under the action of its weight?
- An object is thrown vertically upward. Discuss the sign of acceleration due to gravity, relative to velocity, while the object is in air.
- At what point or points in its path does a projectile have its minimum speed, its maximum speed?
- Can the velocity of an object reverse the direction when acceleration is constant?
- Calculate the work done in kilo joules in lifting a mass of 10 kg (at a steady velocity ) through a vertical height of 10m?

**Q.No3.**** ****Write short Answers to Any Eight (8) questions.**** **** ****(16)**

- A ball of mass m is held at a height h1 above a table. The top is at a height h2 above the floor. One student says that the ball has potential energy mgh1 but another says that it is mg(h1+h2). Who is correct?
- In which case is more work done? When a 50 kg bag of books is lifted through 50cm, or when a 50 kg crate is pushed through 2m across the floor with a force of 50 N?
- Explain what is meant by centripetal force and why it must be furnished to an object if the object is to follow a circular path?
- What is meant by moment of inertia? Explain its significance.
- A disc and a hoop start moving down from the top of an inclined plane at the same time. Which one will be moving faster on reaching the bottom?
- Why fog droplets appear to be suspended in air?
- In an orbiting space station, would the blood pressure in major arteries in the leg ever be greater than the blood pressure in major arteries in the neck?
- A person is standing near a fast moving train. Is there any danger that he will fall towards it?
- Does frequency depends on amplitude for harmonic oscillators?
- Can we realize an ideal simple pendulum?
- What happens to the period of a simple pendulum if its length is doubled? What happened if the suspended mass is doubled?
- What feature do longitudinal waves have in common with transverse waves?

**Q.No4.**** ****Write short Answers to Any Six (6) questions.**** **** ****(12)**

- Explain why sound travels faster in warm air than in cold air.
- In the Young’s experiment, one of the slits is covered with blue filter and other with red filter. What would be the patter of light intensity on the screen?
- Could you obtain Newton’s rings with transmitted light? If yes, would the pattern be different from that obtained with reflected light?
- How would you distinguish between un-polarized and plane – polarized lights?
- Why would it be advantageous to use blue light with a compound microscope?
- A magnifying glass gives a five times enlarged image at a distance of 25 cm from the lens. Find by ray diagram, the focal length of the lens.
- If a person was looking through a telescope at the full moon, how would the appearance of the moon be changed by covering half of the objective lens?
- How the power is lost in optical fibre through dispersion? Explain.
- How the light signal is transmitted through the optical fibre?

**Section II**

**Note:**** ****Attempt Any THREE (3) questions.**** **** **** ****(24)**

**Q.No.5 **

(a) What is projectile motion? Calculate height and time of flight? (5)

(b) A load of 10.0N is suspended from a clothes line. This distorts the line so that it makes and angle of 150with the horizontal at each end. Find the tension in the cloths line? (3)

**Q.No.6**

(a) Explain interconversion of P.E and K.E , also state law of conservation of energy. (5)

(b) A gramophone record turntable acceleration from rest to an angular velocity of 45.0 Rev min-1 in 1.60s. What is its average angular acceleration ? (3)

**Q.No.7**

(a) How energy is conserved in S.H.M.? (5)

(b) A church organ consists of pies, each open at one end, of different length. The minimum length is 30 mm and the longest is 4 m. calculate the frequency range of the fundamental notes. (3)

**Q.No.8**

(a) What is molar specific at constant volume and at constant pressure? Prove that the difference between molar specifics heat at constant press use to molar specific heat at constant volume is equal to universal gas constant. (5)

(b) Water flows through a hose, whose internal diameter is 1cm at a speed of 1ms-1. What should be the diameter of the nozzle if the water is to emerge at 21ms-1? (3)

**Q.No.9**

(a) Discuss the principle and working of Michelson’s interferometer. (5)

(b) A glass light pipe in air will totally internally reflect a light ray if its angle of incidence is at least 390. What is the minimum angle for total internal reflection if pipe is in water?

This guess paper is to help students prepare for their 1st Year Physics Guess Paper 2023 examination. It is based on the key concepts and topics covered in the syllabus. However, please note that the actual examination may contain questions that are not covered in this guess paper and other classes guess papers