Wednesday 30 March 2016

11 th Std Class Physics - Most Importance questions with Answer Key

11 th Std Class Physics - Most Importance questions with Answer Key



UNIT – 1 Nature of the Physical World and Measurement





UNIT – 2 Kinematics





UNIT – 3 Dynamics of Rotational Motion


UNIT – 4 Gravitation and Space Science




UNIT – 5 Mechanics of Solids and Fluids


  
UNIT – 6 Oscillations


UNIT – 7 Wave Motion



UNIT – 8 Heat and Thermodynamics


UNIT – 9 Ray Optics

| Spectrometer |

UNIT – 10 Magnetism



UNIT – 1 Nature of the Physical World and Measurement

1.   What is the role of Physics in technology?

2.    Write a note on the basic forces in nature.

3.    Distinguish between fundamental units and derived units.

4.    Give the SI standard for (i) length (ii) mass and (iii) time.

5.   Why SI system is considered superior to other systems?

6.    Give the rules and conventions followed while writing SI units.

7.    What is the need for measurement of physical quantities?

8.    You are given a wire and a metre scale. How will you estimate the diameter of the wire?

9.    Name four units to measure extremely small distances.

10.                        What are random errors? How can we minimise these errors?

11.                        Show that 12 gt2 has the same dimensions of distance.

12.                        What are the limitations of dimensional analysis?


13.                        What are the uses of dimensional analysis? Explain with one example.
UNIT – 2 Kinematics
1.     Compute the (i) distance travelled and (ii) displacement made by the student when he travels a distance of 4km eastwards and then a further distance of 3 km northwards.

2.     What is the (i) distance travelled and (ii) displacement produced by a cyclist when he completes one revolution?

3.     Differentiate between speed and velocity of a body.

4.     What is meant by retardation?

5.     What is the significance of velocity-time graph?

6.     Derive the equations of motion for an uniformly accelerated body.

7.     What are scalar and vector quantities?

8.     How will you represent a vector quantity?

9.     What is the magnitude and direction of the resultant of two vectors acting along the same line in the same direction?

10.                State: Parallelogram law of vectors and triangle law of vectors.

11.                Obtain the expression for magnitude and direction of the resultant of two vectors when they are inclined at an angle ‘θ’ with each other.

12.                State Newton’s laws of motion.

13.                Explain the different types of inertia with examples.

14.                State and prove law of conservation of linear momentum.

15.                Define impulse of a force

16.                Obtain an expression for centripetal acceleration.

17.                What is centrifugal reaction?
18.                Obtain an expression for the critical velocity of a body revolving in a vertical circle.

19.                What is meant by banking of tracks?

20.                Obtain an expression for the angle of lean when a cyclist takes a curved path.

21.                What are the two types of collision? Explain them.

22.                Obtain the expressions for the velocities of the two bodies after collision in the case of one dimensional motion.

23.                Prove that in the case of one dimensional elastic collision between two bodies of equal masses, they interchange their velocities after collision.

UNIT – 3 Dynamics of Rotational Motion
1.     Obtain an expression for position of centre of mass of two particle system.

2.     Explain the motion of centre of mass of a system with an example.

3.     What are the different types of equilibrium?

4.     Derive the equations of rotational motion.

5.     Compare linear motion with rotational motion.

6.     Explain the physical significance of moment of inertia.

7.     Show that the moment of inertia of a rigid body is twice the kinetic energy of rotation.

8.     State and prove parallel axes theorem and perpendicular axes theorem.

9.     Obtain the expressions for moment of inertia of a ring (i) about an axis passing through its centre and perpendicular to its plane.

10.                        about its diameter and (iii) about a tangent.
11.    Obtain the expressions for the moment of inertia of a circular disc (i) about an axis passing through its centre and perpendicular to its plane.(ii) about a diameter (iii) about a tangent in its plane and (iv) about a tangent perpendicular to its plane.

12.    Obtain an expression for the angular momentum of a rotating rigid body.

13.    State the law of conservation of angular momentum.

14.    A cat is able to land on its feet after a fall. Which principle of physics is being used? Explain.

UNIT – 4 Gravitation and Space Science
1.     Why is the gravitational force of attraction between the two bodies of ordinary masses not noticeable in everyday life?

2.     State the universal law of gravitation.

3.     Define gravitational constant. Give its value, unit and dimensional formula.

4.     The acceleration due to gravity varies with (i) altitude and (ii) depth. Prove.

5.     Discuss the variation of g with latitude due to the rotation of the Earth.

6.     The acceleration due to gravity is minimum at equator and maximum at poles. Give the reason.

7.     What are the factors affecting the ‘g’ value?

8.     Why a man can jump higher on the moon than on the Earth?

9.     Define gravitational field intensity.

10.    Define gravitational potential.

11.    Define gravitational potential energy. Deduce an expression for it for a mass in the gravitational field of the Earth.

12.    Obtain an expression for the gravitational potential at a point.

13.                        Differentiate between inertial mass and gravitational mass.
14.    The moon has no atmosphere. Why?

15.    What is escape speed? Obtain an expression for it.

16.    What is orbital velocity? Obtain an expression for it.

17.    What will happen to the orbiting satellite, if its velocity varies?

18.    What are the called geo-stationary satellites?

19.    Show that the orbital radius of a geo-stationary satellite is 36000 km.

20.    Why do the astronauts feel weightlessness inside the orbiting spacecraft?

21.    Deduce the law of periods from the law of gravitation.

22.    State and prove the law of areas based on conservation of angular momentum.

23.    State Helio-Centric theory.

24.    State Geo-centric theory.

25.    What is solar system?

26.    State Kepler’s laws of planetary motion.

27.    What is albedo?

28.    What are asteroids?

29.    What are constellations?

1.     Write a note on Milky Way.

UNIT – 5 Mechanics of Solids and Fluids
1.     State Hooke’s law.

2.     Explain the three moduli of elasticity.

3.     Describe Searle’s Experiment.

4.     Which is more elastic, rubber or steel? Support your answer.

5.     State and prove Pascal’s law without considering the effect of gravity.

6.     Taking gravity into account, explain Pascal’s law.

7.     Explain the principle, construction and working of hydraulic brakes.

8.     What is Reynold’s number?

9.     What is critical velocity of a liquid?

10.Why aeroplanes and cars have streamline shape?

11.                        Describe an experiment to determine viscosity of a liquid.
12. What is terminal velocity?

13.Explain Stoke’s law.

14.Derive an expression for terminal velocity of a small sphere falling through a viscous liquid.

15.Define cohesive force and adhesive force. Give examples.

16.Define i) molecular range ii) sphere of influence iii) surface tension.

17.Explain surface tension on the basis of molecular theory.

18. Establish the relation between surface tension and surface energy.

19. Give four examples of practical application of surface tension.

20. How do insects run on the surface of water?

21. Why hot water is preferred to cold water for washing clothes?

22.Derive an expression for the total energy per unit mass of a flowing liquid.

23. State and prove Bernoulli’s theorem.

24.Why the blood pressure in humans is greater at the feet than at the brain?

25. Why two holes are made to empty an oil tin?

26.A person standing near a speeding train has a danger of falling towards the train. Why?

27.Why a small bubble rises slowly through a liquid whereas the bigger bubble rises rapidly?

UNIT – 6 Oscillations
1.     Define simple harmonic motion. What are the conditions of SHM?

2.     Every SHM is periodic motion but every periodic motion need not be SHM. Why? Support your answer with an example.

3.     Show that the projection of uniform circular motion on the diameter of a circle is simple harmonic motion.

4.     Explain : (i) displacement (ii) velocity and (iii) acceleration in SHM using component method.

5.     Show graphically the variation of displacement, velocity and acceleration of a particle executing SHM.

6.     What is the phase difference between (i) velocity and acceleration

a.     acceleration and displacement of a particle executing SHM?
7.     Derive the differential formula for SHM.

8.     Define the terms (i) time period (ii) frequency and (iii) angular frequency.

9.     Define force constant. Give its unit and dimensional formula.

10.    What is phase of SHM? Explain the term phase difference.

11.    Derive an expression for the time period of a body when it executes angular SHM.

12.    What is an epoch? Give its unit.

13.    Explain the oscillations of a mass attached to a horizontal spring. Hence deduce an expression for its time period.

14.    Obtain an expression for the frequency of vertical oscillations of a loaded spring.

15.    Distinguish between linear and angular harmonic oscillator?

16.    What is a spring factor?

17.    Show that the oscillations of a simple pendulum are simple harmonic. Hence deduce the expression for the time period.

18.    The bob of a simple pendulum is a hollow sphere filled with water. How does the period of oscillation change if the water begins to drain out of the sphere?

19.    Why does the oscillation of a simple pendulum eventually stop?
1.     What will happen to the time period of a simple pendulum if its length is doubled?

2.     Derive an expression for the total energy of a particle executing SHM.

3.     On what factors the natural frequency of a body depend on?

4.     What is forced vibration? Give an example.

5.     What forces keep the simple pendulum in SHM?

6.     Illustrate an example to show that resonance is disastrous sometimes.

7.     If two springs are connected in parallel, what is its equivalent spring constant?

UNIT – 7 Wave Motion
1.     Define wave motion. Mention the properties of the medium in which a wave propagates.

2.     What are the important characteristics of wave motion?

3.     Distinguish between transverse and longitudinal waves.

4.     In solids both longitudinal and transverse waves are possible, but transverse waves are not produced in gases. Why?

5.     Define the terms wavelength and frequency in wave motion. Prove that v = nλ.

6.     Obtain an expression for the velocity of transverse wave in a stretched string, when it is vibrating in fundamental mode.

7.     Derive Newton - Laplace formula for the velocity of sound in gases.


8.     Show that the velocity of sound increases by 0.61 m s-1 for every degree rise of temperature.
9.     Obtain the equation for plane progressive wave.

10.    Distinguish between intensity and loudness of sound.

11.    What do you understand by decibel?

12.    On what factors does the intensity of sound depend?

13.    What is an echo? Why an echo cannot be heard in a small room?

14.    Write a short note on whispering gallery.

15.    State the principle of superposition.

16.    What are the essential conditions for the formation of beats?

17.    What are beats? Show that the number of beats produced per second is equal to the difference in frequencies.

18.    What is interference of sound waves? Describe an experiment to explain the phenomenon of interference of waves.

19.    How are stationary waves formed?

20.    Derive the equation of stationary wave and deduce the condition for nodes and antinodes.

21.    What are the properties of stationary waves?

22.    State the laws of transverse vibrations in stretched strings.

23.    List out the differences between a progressive wave and a stationary wave.


24.    What are overtones and harmonics?

25.    Why open organ pipes are preferred for making flute?

26.    Prove that in a pipe closed at one end, frequency of harmonics are in the ratio 1:3:5.

27.    Explain how overtones are produced in an open pipe. Show that all harmonics are present in the open pipe.

28.    What is meant by end correction?

29.    What is doppler effect? Derive the formula for the change in frequency (i) when the source is approaching and receding from
a.     the observer and (ii) when the source is stationary and observer is moving towards and away from the source.

UNIT – 8 Heat and Thermodynamics
1.     What are the postulates of Kinetic theory of gases?

2.     Derive an expression for the average kinetic energy of the molecule of gas.


3.     Two different gases have exactly the same temperature. Do the molecules have the same RMS speed?

4.     Explain internal energy. What is its value in one complete cyclic process?


What are degrees of freedom?
1.     State the law of equipartition of energy and prove that for a diatomic
2.     Distinguish between isothermal and adiabatic process

3.     Define isothermal process. Derive an expression for the work done during the process.

4.     A gas has two specific heats, whereas liquid and solid have only one. Why?

5.     Derive an expression for the work done in one cycle during an adiabatic process

6.     Define molar specific heat at constant pressure.

7.     Derive Meyer’s relation.

8.     What is an indicator diagram?

9.     Distinguish between reversible process and irreversible process with examples.

10.    Is it possible to increase the temperature of a gas without the addition of heat? Explain.

11.    On driving a scooter for a long time the air pressure in the tyre slightly increases why?

12.    How is second law of thermodynamics different from first law of thermodynamics?

13.    Define Clausius statement.
14.    Describe the working of Carnot engine and derive its efficiency.

15.    Give an example for a heat pump.

16.    A heat engine with 100% efficiency is only a theoretical possibility. Explain.


17.    What is Coefficient of Performance? Derive the relation between COP and efficiency.

18.    Why are ventilators provided in our houses?

19.    Define temperature gradient.

20.    Define steady state in thermal conduction of heat.

21.    What are the factors upon which coefficient of thermal conductivity depends?


22.    Write the applications of Kirchoff’s law.

23.    Define absorptive power.

24.    Define Stefan’s law.

25.    Explain Fery’s concept of a perfect black body.

26.    State Wien’s displacement law.

27.    State Newton’s law of cooling. Explain the experimental verification of Newton’s law of cooling.

28.    Why does a piece of red glass when heated and taken out glow with green light?

29.    Define solar constant.

30.    Describe the working of pyrheliometer.
UNIT – 9 Ray Optics
1.     State the laws of reflection.

2.     Show that the reflected ray turns by 2θ when mirror turns by θ.

3.     Explain the image formation in plane mirrors.

4.     Draw graphically the image formation in spherical mirrors with different positions of the object and state the nature of the image.

5.     What is the difference between the virtual images produced by

a.     plane mirror (ii) concave mirror (iii) convex mirror

6.     The surfaces of the sun glasses are curved, yet their power may be zero. Why?
7.     Prove the mirror formula for reflection of light from a concave mirror producing (i) real image (ii) virtual image.

8.     With the help of ray diagram explain the phenomenon of total internal reflection. Give the relation between critical angle and refractive index.


9.     Write a note on optical fibre.

10.    Explain Michelson’s method of determining velocity of light.

11.    Give the importance of velocity of light.

12.    Derive lens maker’s formula for a thin biconvex lens.

13.    Define power of a lens. What is one dioptre?
14.    Does a beam of white light disperse through a hollow prism?

15.    Derive an equation for dispersive power of a prism.

16.    Describe a spectrometer.

17.    Explain how will you determine the angle of the minimum deviation of a prism using spectrometer.

18.    Write a note on formation of rainbows.
UNIT – 10 Magnetism
1.     State Coulomb’s inverse square law.

2.     Obtain the expressions for the magnetic induction at a point on the (i) axial line and (ii) equatorial line of a bar magnet.

3.     Find the torque experienced by a magnetic needle in a uniform magnetic field.

4.     State and prove tangent law.
5.     What is tan A position? How will you set up the deflection magnetometer in tan A position?

6.     Explain the theory of tan A position. Explain how will you compare the magnetic moments of two bar magnets in this position.

7.     What is tan B position? How will you set up the deflection magnetometer in tan B position?

8.     Explain the theory of tan B position. Explain how will you compare the magnetic moments of two bar magnets in this position.

9.     Define the terms (i) magnetic permeability (ii) intensity of magnetisation and (iii) magnetic susceptibility.

10.    Distinguish between dia, para and ferro magnetic substances. Give one example for each.

11.    Explain the hysteresis cycle.



SYLLABUS (180 periods)

UNIT – 1 Nature of the Physical World and Measurement (7 periods)

Physics – scope and excitement – physics in relation to technology and society.

Forces in nature – gravitational, electromagnetic and nuclear forces (qualitative ideas)

Measurement – fundamental and derived units – length, mass and time measurements.

Accuracy and precision of measuring instruments, errors in measurement – significant figures.

Dimensions - dimensions of physical quantities - dimensional analysis – applications.

UNIT – 2 Kinematics (29 periods)

Motion in a straight line – position time graph – speed and velocity – uniform and non-uniform motion – uniformly accelerated motion – relations for uniformly accelerated motions.

Scalar and vector quantities – addition and subtraction of vectors, unit vector, resolution of vectors - rectangular components, multiplication of vectors – scalar, vector products.

Motion in two dimensions – projectile motion – types of projectile

– horizontal and oblique projectile.

Force and inertia, Newton’s first law of motion.

Momentum – Newton’s second law of motion – unit of force – impulse.

Newton’s third law of motion – law of conservation of linear momentum and its applications.

Equilibrium of concurrent forces – triangle law, parallelogram law and Lami’s theorem – experimental proof.

Uniform circular motion – angular velocity – angular acceleration

– relation between linear and angular velocities. Centripetal force – motion in a vertical circle – bending of cyclist – vehicle on level circular road – vehicle on banked road.

Work done by a constant force and a variable force – unit of

work.







Energy – Kinetic energy, work – energy theorem – potential energy

– power.

Collisions – Elastic and in-elastic collisions in one dimension.


UNIT – 3 Dynamics of Rotational Motion (14 periods)

Centre of a two particle system – generalization – applications – equilibrium of bodies, rigid body rotation and equations of rotational motion. Comparison of linear and rotational motions.

Moment of inertia and its physical significance – radius of gyration

– Theorems with proof, Moment of inertia of a thin straight rod, circular ring, disc cylinder and sphere.

Moment of force, angular momentum. Torque – conservation of angular momentum.


UNIT – 4 Gravitation and Space Science (16 periods)

The universal law of gravitation; acceleration due to gravity and its variation with the altitude, latitude, depth and rotation of the Earth.
– mass of the Earth. Inertial and gravitational mass.

Gravitational field strength – gravitational potential – gravitational potential energy near the surface of the Earth – escape velocity – orbital velocity – weightlessness – motion of satellite – rocket propulsion

– launching a satellite – orbits and energy. Geo stationary and polar satellites – applications – fuels used in rockets – Indian satellite programme.

Solar system – Helio, Geo centric theory – Kepler’s laws of planetary motion. Sun – nine planets – asteroids – comets – meteors – meteroites

– size of the planets – mass of the planet – temperature and atmosphere.

Universe – stars – constellations – galaxies – Milky Way galaxy - origin of universe.


UNIT – 5 Mechanics of Solids and Fluids (18 periods)

States of matter- inter-atomic and inter-molecular forces.

Solids – elastic behaviour, stress – strain relationship, Hooke’s law – experimental verification of Hooke’s law – three types of moduli of elasticity – applications (crane, bridge).

Pressure due to a fluid column – Pascal’s law and its applications (hydraulic lift and hydraulic brakes) – effect of gravity on fluid pressure.







Surface energy and surface tension, angle of contact – application of surface tension in (i) formation of drops and bubbles (ii) capillary rise (iii) action of detergents.

Viscosity – Stoke’s law – terminal velocity, streamline flow – turbulant flow – Reynold’s number – Bernoulli’s theorem – applications

– lift on an aeroplane wing.

UNIT – 6 Oscillations (12 periods)

Periodic motion – period, frequency, displacement as a function of time.

Simple harmonic motion – amplitude, frequency, phase – uniform circular motion as SHM.

Oscillations of a spring, liquid column and simple pendulum – derivation of expression for time period – restoring force – force constant. Energy in SHM. kinetic and potential energies – law of conservation of energy.

Free, forced and damped oscillations. Resonance.

UNIT – 7 Wave Motion (17 periods)

Wave motion- longitudinal and transverse waves – relation between v, n, λ.

Speed of wave motion in different media – Newton’s formula – Laplace’s correction.

Progressive wave – displacement equation –characteristics.

Superposition principle, Interference – intensity and sound level

– beats, standing waves (mathematical treatment) – standing waves in strings and pipes – sonometer – resonance air column – fundamental mode and harmonics.

Doppler effect (quantitative idea) – applications.


UNIT – 8 Heat and Thermodynamics (17 periods)

Kinetic theory of gases – postulates – pressure of a gas – kinetic energy and temperature – degrees of freedom (mono atomic, diatomic and triatomic) – law of equipartition of energy – Avogadro’s number.

Thermal equilibrium and temperature (zeroth law of thermodynamics) Heat, work and internal energy. Specific heat – specific



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