# 1st Year Physics Important Questions Guess Paper 2021

If you are a student of fsc 1st year and looking for the important short and long questions then here we have shared the 1st Year Physics Important Questions Guess Paper 2021.

Most Important short Questions

### Chapter No.1 Measurements

2) Differentiate between random and systematic error?

3) Find the dimension of ŋ used in equation F= 6πŋrv.?

4) Write down the dimension of Pressure and density?

5) Find out the dimension and unit of G used in equation F=G m_(1m_2 )/r^2

6) Show that E=mc2 dimensionally correct?

7) The period of a simple pendulum is measured by stopwatch .what type of errors are possible in the time period?

8) Why do we find it useful to have two units for the amount of substance kilogram and mole?

9) Give draws backs to use the period of a simple pendulum as a time standard? 10) How many meters is a light-year?

11) How many seconds in a year and how many years in a nanosecond?

### Chapter No. 2 Vectors and Equilibrium

1) Two vectors have unequal magnitude can their sum be equal to zero?

2) Can a vector have a component greater than vector magnitude?

3) Can a body rotate about its center of gravity under the action of its weight?

4) If one of the rectangular components of the vector is not zero, can its magnitude by zero, explain?

5) Name Three condition which makes →┬A X →┬A =0?

6) Can you add zero to the null vector?

7) If →┬A +→┬B =→┬0what can you say about its components?

8) Define the position vector and Unit vector?

### Chapter No.3 Motion and Force

1) Show that the rate of change of momentum is equal to force?

2) Derive the expression for the range of projectile?

3) Can the velocity of an object reverse the direction when acceleration is constant? If so give an example?

4) An object is thrown vertically upward. Discuss the sign of acceleration due to gravity, relative to velocity, while the object is in the air?

5) Explain the circumstance when A) a and v are parallel B) v is zero but a is not zero? 6) Differentiate between elastic and inelastic collision?

### Chapter No.4 Work and Energy

1) Calculate work done in kilojoule in lifting a mass of 10kg through a vertical height of 10m?

2) When a rocket re-enters the atmosphere, its nose cone becomes very hot? Why

3) A girl drops a cup from a certain height which breaks into pieces. What energy changes are involved?

4) A boy uses a catapult to throw a stone which accidentally smashes a green hose window. What energy changes are involved?

5) Show that 1kWh = 3.6 x106J.

### Chapter No.5 Circular Motion

1) what is centripetal force give its significance?

2) Define the moment of inertia to give its significance?

3) Why does the diver change his body position before diving in the pool?

4) Differentiate between Tangential and angular velocity?

5) Describe what should be the minimum velocity for a satellite to orbit close to the earth around it?

6) When Mud flies off the tire of a moving bicycle, in what direction does it fly. Explain?

### Chapter No.6 Fluid Dynamics

1) Define Viscosity?

2) Why fog droplets appear to be suspended in the air?

3) Differentiate between Streamline and turbulent flow?

4) A person is standing near a fast-moving train is there any danger he will fall toward it?

5) Explain the working of the carburetor?

6) How swing is produced in a fast-moving cricket ball?

### Chapter no.7 Oscillation

1) Write down the characteristics of S.H.M?

2) Can we realize an ideal Simple Pendulum?

3) What happens to the period of a simple pendulum if its length is doubled? And if its mass doubled?

4) What is meant by Phase Angle?

5) Describe some common Phenomena in which resonance plays an important role?

6) Does frequency depends upon amplitude for the harmonic oscillator?

### chapter no.8 Waves

1) Explain why sound travels faster in warm air than in cold air?

2) Explain term node antinode, crest, Trough?

3) How are beats are useful in tuning musical instruments?

4) As a result of a distant explosion an observer senses a ground tremor and then heat the explosions. Explain the time difference?

5) What is the effect of variation of density on the speed of sound in a gas?

6) What are the common features in longitudinal and transverse waves?

7) Why does sound travel faster in solid as compared to gasses?

### Chapter no.9 Physical Optics

1) Under what conditions two sources of light behave as coherent?

2) Can visible light produce Interference fringes? Explain?

3) An oil film spread over a wet footpath shows colors. Explain How does it happen?

4) How would distinguish between Un-polarized and plane-polarized light?

5) Why Sun glasses are better than ordinary sunglasses?

### Chapter No.11 Heat and Thermodynamics

1) Does the entropy of a system increase or decrease due to friction explain?

2) why the average velocity of the molecule in a gas zero but average the square of velocity is not?

3) Is It possible to convert internal energy into mechanical energy? Explain with an example?

4) State 1st law of thermodynamic? How it is applicable to the human body?

5) Write four postulates of the kinetic theory of gases?

6) A Thermo flask containing milk as a system is shaken rapidly. Does the temperature of

milk rise?

7) Can mechanical energy be converted completely into heat energy? If so give example?

8) Prove that CP-CV=R

### Important Long Questions

Scalar product,

Cross product,

Torque,

Law of Conservation of Momentum

Elastic collision in one dimension,

Projectile Motion,

Work done by Gravitational Field,

Work done by variable force,

Absolute Potential Energy,

Interconverstion of P.E and K.E

Centripetal force,

Moment of Inertia,

Rotational K.E of disc and hoop,

Artificial Gravity,

Geostationary Orbit,

Terminal velocity,

Equation of Continuity, Simple Pendulum,

Energy Conservation In SHM, SHM, And Uniform Circular Motion,

Speed of Sound in air,

Doppler Effect,

Young's Double Slit Experiment,

Michelson's Interferometer

Diffraction Of X-Rays by Crystal,

Simple Microscope.

Compound Microscope,

Pressure of gas

Molar specific heats of a gas,

Carnot engine and Carnot Theorem,

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