Most Asked Long Question Of 11th Physics
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Vector
1. State the parallelogram law of vector addition. Derive expression for the magnitude and direction of the resultant of two vectors inclined at an angle θ from each other.
2. State triangle law of vector addition. Obtain an expression for the resultant of two vectors P and Q inclined at angle θ .
Kinematics
1. A projectile is fired at an angle of θ with the horizontal. Show that its trajectory is a parabola. Also, derive expressions for the maximum height attained and the time of flight.
Laws of Motion
1. Define angle of friction and angle of repose. Establish a relation between them.
2. State and explain the principle of conservation of linear momentum. Hence derive it from Newton's law of motion.
3. State Newton's laws of motion. Show that Newton's first law of motion defines force and second law of motion defines the unit of force.
4. Explain the difference between conservative and non-conservative forces. Also state and prove law of conservation of linear momentum.
5. State the laws of limiting friction. How would you measure the coefficient of friction between a body and an inclined plane/
Work and Energy
1.What is the physical difference between elastic and inelastic collision? Prove that the colliding object having same masses exchange their velocities in one dimensional elastic collision.
2. What is the principle of conservation of energy? Show that total mechanical energy of a body is conserved when it moves under the action of gravitational field.
3. What do you mean by elastic and inelastic collision? Write with one example of each. Show that the sum of kinetic energy and potential energy of a freely falling body remains constant at any instant.
4. What do you mean by variable force? Derive an expression for work done by a variable force.
5. What is elastic collision? Show that in an elastic collision between two particles, the relative velocity of separation after collision is equal to the relative velocity of approach before collision.
Circular Motion
1. Define centripetal force. Show that the acceleration of the body moving in a circular path of radius r with uniform speed v is v^2/r and draw a diagram to show the direction of the acceleration.
2. What is meant by banking of a road? Discuss the motion of a vehicle round a banked circular track and obtain an expression for the banking angle in terms of speed of the vehicle.
3. What is conical pendulum? Obtain an expression for its time period.
4. Define centripetal force. Derive it in the case of motion of a bi-cycle on a curved road.
5.Explain what is meant by angular velocity.
Gravitation
1. What is escape velocity? Derive an expression for it on the surface of the earth.
2. Obtain an expression for variation of ' g ' with rotation of earth.
3. What is geostationary satellite ? Derive an expression for the time period of the satellite revolving around the earth?
4. Define gravitational potential energy and derive its expression.
5. Explain the concept of geostationary satellite. Find an expression for the total energy of the moon revolving around the earth.
6. Derive an expression for the variation of acceleration due to gravity of the earth with the altitude and explain its meaning.
7. How does acceleration due to gravity vary with distance from the centre of earth above and below its centre?
8. What is satellite? Calculate the orbital velocity of an artificial satellite.
Equilibrium
1. State principle of moments . Explain how you verify the principle of moment in your laboratory.
Rotational Dynamics
1. Define moment of inertia. Derive an expression for the moment of inertia of thin uniform rod about an axis through its center and perpendicular to its length.
2. Explain the concept of torque and angular acceleration in the case of a rigid body. Derive a relation between them.
3. State and explain the principle of conservation of angular momentum with example.
4. Define torque and couple in rotational motion. Also derive an expression for the work done by a couple.
5. Define moment of inertia. How is it related with angular momentum of a body rotating about an axis of rotation?
6. Define moment of inertia and radius of gyration. Derive an expression for the kinetic energy of rotation of a rigid body.
Elasticity
1. Define elastic limit and young's modulus of elasticity. How can you determine the young 's modulus for a material in the laboratory? Explain.
2. Explain Hooke's law with necessary figure and derive and expression for the energy density in a stretched wire.
3. Derive an expression for the energy stored in a stretched string. .Define the term energy density of a body under strain.
4. What are the proportional limit and the elastic limit? Derive an expression for the energy stored in a stretched wire.
5. Define stress and strain.Derive an expression for the energy stored in a stretched wire.
Periodic Motion
1. What is simple harmonic motion? Calculate the total energy of a particle executing simple harmonic motion.
2. What is a simple Pendulum? Show that motion of the bob of a simple pendulum is simple harmonic. Obtain an expression for its frequency.
3. Show that the small oscillations of a mass loaded spring suspended vertically are simple harmonic. Deduce expression for its time period.
4. What is simple harmonic motion. Derive the relation between the acceleration and displacement of the practicle executing S.H.M
5. Obtain an expression for the time period of a mass ' m ' attached with a spring placed horizontally on a smooth table.
Surface tension
1. What is capillarity? Deduce a relation for the height of liquid column rise in a capillary tube when one end is dipped in the liquid.
2. Define surface tension and angle of contact. Deduce an expression for rise of a liquid in a capillary tube.
3. Prove that the surface energy and surface tension are numerically same. Explain the concept of the angle of contact, with necessary figure, when the surface of the liquid is convex if viewed from the above.
Viscosity
1. State and prove Bernoulli's principle.
2. Describe Stoke's method to find the coefficient of viscosity of liquid in the laboratory with necessary theory.
3. What is terminal velocity? Derive an expression for the terminal velocity of a small spherical body falling through a viscous fluid.
4. State Stoke's law and deduce it from dimensional analysis. Define coefficient of viscosity of a liquid.
5. Derive Newton's formula for viscous force Define coefficient of viscosity. Calculate its dimensions.
Heat and Temperature
1. Describe a method to determine the linear expansivity of a solid. Can the cubical expansivity be derived from this value?
2. Describe how the cubical expansivity of a liquid can be determined by the use of balanced columns.
3. Define the coefficients of real expansion and apparent expansion and hence derive the relation between them.
4. Define linear and cubical expansivity of solids. Establish a relationship between the coefficient of linear and cubical expansions.
5. Does cubical expansivity depends upon the initial volume of a solid ? Write the unit of this expansivity. Also derive its relation with superficial expansivity.
Quantity of Heat
1. What is meant by heat capacity? Describe the method of mixture to determine specific heat capacity of a solid.
2. State Newton's law of cooling. Use it to find the specific heat capacity of a unknown liquid.
3. What is the difference between the "specific heat capacity" and "latent heat" ? Describe in brief, the laboratory experiment for the determination of latent heat of fusion of ice.
4. Describe the method to determine latent heat of vaporization of water in laboratory.
Thermal Properties Of Matter
1. State Boyle's law and Charle's laws. Describe how these laws are combined to derive ideal gas law.
2. Derive ideal gas equation on the basis of kinetic theory of a gas.
3. Define volume coefficient and pressure coefficient. How pressure coefficient and volume coefficient are related?
4. Derive an expression for the pressure exerted by an ideal gas on the basis of kinetic theory.
Transfer of Heat
1. On what factors the thermal conductivity of a solid depends? Describe, Searle's experimental method to determine the thermal conductivity of a solid.
2. State and explain Stefan's law of black body radiation. Can a perfect black body be realized in practice?
3. What do you mean by thermal conductivity of a substance? Deduce an expression for the thermal conductivity of a good conductor in steady state.
4. What is radiation and how does this mode of heat transfer differ from condition and convection?
First Law Of Thermodynamics
1. What is adiabatic process? Derive an expression for the work done in this process.
2. State and explain first law of thermodynamics. Derive the relation, Cp-Cv = R , Where the symbols have their usual meanings.
3. What do you understand by isothermal and adiabatic process? Derive PV = constant , where symbols have their usual meaning.
4. What is thermodynamic process? Describe different thermodynamic process.
5. What do you mean by isothermal process? Obtain an expression for the work done by an ideal gas in the isothermal process.
Second Law Of Thermodynamics
1. Describe the working principle of diesel engine with the help of PV diagram.
2. Describe the working principle of petrol engine with the help of its PV diagram.
3. Describe the working of carnot's engine with the help of its P-V diagram.
4. State and explain second of thermodynamics. Define the efficiency of a heat engine and explain qualitatively why the efficiency of such an engine is always less than 100% ?
Reflection at Curved Mirrors
1. Derive mirror formula for a comcave mirror and state the sign convention used.
2. How will you make difference between real and virtual images? Obtain an expression for the relation object distance, image distance and the focal length in the case of a convex mirror.
Refraction At Plane Surfaces
1. What do you mean by critical angle and total internal reflection? Derive a relation between critical angle and refractive index.
2. Define lateral shift and derive an expression for it due to a parallel edged glass slab.
3. What causes the bending of light when it passes from one medium to another medium?
Deduce the relation, mue = real depth / apparent depth .
Refraction Through Prisms
1. What is prism? Show that the deviation produced by a small angle prism is independent of the angle of incidence, provided the angle of incidence is small.
2. What do you mean by minimum deviation of light when passing through a prism ? Show that the deviation produced by a small angle prism is independence of angle of incidence.
3. Explain with necessary theory of measuring the refractive index of a prism by minimum deviation method.