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FINAL EXAM GENERAL PHYSICS I

Sunday, January 7, 2024

Total Score: 100

Duration: 120 minutes

Exams Guidelines

All the students are directed to follow the instructions below for attempting the exam.

a. While attempting the numerical problems, please follow the general instructions as follows, which means you’ll definitely lose marks if you’ll not follow this way.

i. Given Data   You must write the values of the parameters given in the numerical under the heading of “Given data”.   2 Marks

ii. To Find   You must mention what is being asked to find under the heading of “To find”.   1 Mark

iii. Formula Applied   You have to write the formula through which you can find the answer under the heading of “Formula applied”.   1 Mark

iv. Calculations   All the calculations must be done under the heading of “Calculations”.   6 Marks

b. Try to elaborate the answers through equations and figures where needed.

c. Time is fixed so no student would be given extra time to solve the paper. Therefore, manage your time carefully.

Part-I                    Multiple Choice Questions                    10 Marks

1 Stokes law holds for

a. Cylindrical bodies

b. Cubical bodies

c. Spherical bodies

d. None of these

2 The dimension of frequency is

a. [T]

b. [T-1 ]

c. [T-2 ]

d. [TT-1 ]

3 Polyatomic real gas molecules have

a. Translational K.E.

b. Vibrational K.E.

c. Rotational K.E.

d. All of these

4 Work done by the system on its environment is considered as

a. Positive

b. Negative

c. Both positive and negative

d. None of them

5 The internal energy is equal to

a. Sum of all forms of molecular energies

b. Difference of all forms of molecular energies

c. Product of all forms of molecular energies

d. none

6 The time-displacement graph of SHM is

a. Pulse wave

b. Square wave

c. Sine wave

d. All

7 If the temperature rises, the coefficient of viscosity of a liquid

a. Decreases

b. Increases

c. Remains unchanged

d. None of these

8 Angular velocity is related to angular frequency by equation

a. ω = 2πT

b. ω = f/2π

c. f = 2πω

d. ω = 2πf

9 The word fluid means

a. To resist

b. To flow

c. To walk

d. None of these

10 The First law of thermodynamics was stated in the form of Q = ∆U + ∆W by

a. Joule

b. Claudius

c. Kelvin

d. Newton

Part-II                             Short Questions                     20 Marks

1 How the longitudinal periodic waves are represented by waveform?

2 What do you know about Progressive or travelling waves? Also describe its types.

3 What do you know about the intensity of sound?

4 Derive the expression of work done by ideal gas.

5 Differentiate among the laminar and turbulent flow.

Part-III                             Numerical Problems                      70 Marks

1 Certain globular protein particle has a density of 1246 kg/m3 . It falls through pure water (η = 8 × 10−4Nm−2 s ) with a terminal speed of 3 cm/h. Find the radius of the particle.

2 Two cars P and Q are travelling along a motorway in the same direction. The leading car P travels at the steady speed of 12 m/s; the other car Q, travelling at the steady speed of 20 m/s, sounds its horn to emit a steady note which P’s driver estimate, hasa frequency of 830 Hz. What frequency does Q’s 8own driver hear? (Speed of sound = 340 m/s).

3 A thermodynamic system undergoes a process in which its internal energy decreases by 300 J. If at the same time 120 J of work is done on the system, fine the heat lost by the system.

4 How large must a heating duct be if air moving 3 m/s along it can replenish the air in a room of 300 m3 volume every 15 min? Assume the air’s density remains constant.

5 What stress would cause a wire to increase in length by 0.01% if the Young's modulus of the wire is 12 x 1010 Pa. What force would produce this stress if the diameter of the wire is 0.56 mm?

6 A gas is enclosed in a container fitted with a piston of cross-sectional area 0.10 m2. The pressure of the gas is maintained at 8000 Nm-2 . When heat is slowly transferred, the piston is pushed up through a distance of 4 cm. If 42 J heat is transferred to the system during the expansion, what is the change in internal energy of the system?4 Final Exam General Physics I

7 Water flows through a hose, whose internal diameter is 1 cm at a speed of 1 m/s. What should be the diameter of the nozzle if the water is to emerge at 21 m/s?