Important Definitions & Formulas
Class XI Physics | Board Exam Special
1. Units and Measurements
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1.
Define Measurement. What is a Unit? List the essential characteristics of a standard unit.
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2.
Differentiate between Fundamental (Base) Quantities and Derived Quantities. Give the SI Unit and Dimensional Formula for two examples of each.
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3.
What is a System of Units? List the 7 Fundamental Units and 2 Supplementary Units in the SI system with their symbols.
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4.
Define the following Practical Units of Length and write their values in meters:
a) Astronomical Unit (AU)
b) Light Year (ly)
c) Parallactic Second (Parsec) -
5.
Define the following Units of Time:
a) Solar Day & Solar Year
b) Lunar Month
c) Shake (Write its value in seconds) -
6.
Distinguish between Accuracy and Precision in measurement with a suitable example.
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7.
Define Error in Measurement. Explain the causes and methods to minimize the following types of errors:
a) Systematic Error
b) Gross Error
c) Least Count Error
2. Motion in a Straight Line
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8.
Define Rest and Motion. Explain the concept of Frame of Reference.
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9.
Define Path Length (Distance) and Displacement. Write their SI Units and Dimensional Formulas. Distinguish between them.
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10.
Define Uniform Motion and Non-Uniform Motion. Give one example of each.
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11.
Define Average Velocity and Average Speed. Write their mathematical formulas, SI Units, and Dimensional Formulas.
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12.
Define Instantaneous Velocity. Write its mathematical formula using limits.
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13.
Define Acceleration. Write its formula, SI Unit, and Dimensional Formula. Distinguish between Average Acceleration and Instantaneous Acceleration.
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14.
Write the three Kinematic Equations for uniformly accelerated motion. Under what condition are these equations valid?
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15.
What is Free Fall? Write the equations of motion for a freely falling body under gravity (assuming \( u=0 \)).
3. Motion in a Plane
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16.
Define Scalar Quantity and Vector Quantity. Give two examples of each along with their SI units.
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17.
Define Position Vector and Displacement Vector. Write their mathematical expressions.
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18.
Define the following types of vectors:
a) Equal Vector, Negative Vector
b) Parallel Vectors, Anti-Parallel Vectors
c) Collinear Vector, Co-initial Vector
d) Coplanar Vector, Orthogonal Vector
e) Zero (Null) Vector -
19.
Define Unit Vector. Write its formula, notation, and significance. What is the unit vector of \( \vec{A} \)?
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20.
State the Triangle Law, Parallelogram Law, and Polygon Law of vector addition.
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21.
What is meant by the Resolution of a Vector? Write the expressions for rectangular components (\(A_x, A_y\)) of a vector in a plane.
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22.
Define Scalar Product (Dot Product). Write its formula. Is the result a scalar or vector?
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23.
Define Vector Product (Cross Product). Write its formula. How is the direction of the resultant vector determined?
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24.
Define Projectile Motion. Write the equation of the Trajectory of a Projectile.
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25.
Write the formulas for the following in Projectile Motion:
a) Time of Flight (T)
b) Horizontal Range (R)
c) Maximum Height (H) -
26.
Define Uniform Circular Motion. Is it an accelerated motion?
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27.
Define the following Angular Quantities. Write their SI Units and Dimensional Formulas:
a) Angular Displacement (\( \theta \))
b) Angular Velocity (\( \omega \))
c) Angular Acceleration (\( \alpha \)) -
28.
Define Centripetal Acceleration. Write its formula in terms of linear velocity (\(v\)) and angular velocity (\( \omega \)). Write its SI unit and dimensional formula.
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29.
Distinguish between Centripetal Force and Centrifugal Force. Write the formula for Centripetal Force.
4. Laws of Motion
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30.
Define Inertia. Explain the following with examples:
a) Inertia of Rest
b) Inertia of Motion
c) Inertia of Direction -
31.
State Newton's First Law of Motion (Galileo's Law of Inertia).
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32.
Define Linear Momentum. Write its formula, SI Unit, and Dimensional Formula. Is it a scalar or vector quantity?
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33.
State Newton's Second Law of Motion. Write the mathematical relation between Force, Mass, and Acceleration.
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34.
Define Impulse. Write its formula, SI Unit, and Dimensional Formula. State the Impulse-Momentum Theorem.
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35.
State the Law of Conservation of Linear Momentum. Write the mathematical condition for it.
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36.
State Newton's Third Law of Motion. What are the essential conditions for forces to form an Action-Reaction pair?
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37.
Distinguish between Inertial Frames and Non-Inertial Frames of Reference with examples.
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38.
What is Normal Reaction (Normal Force)? Why is it always perpendicular to the contact surface?
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39.
Define Friction. Explain the following types with their definitions:
a) Static Friction
b) Limiting Friction
c) Kinetic Friction
d) Rolling Friction -
40.
Define Angle of Friction and Angle of Repose. Write the relation between them.
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41.
What is meant by Banking of Roads? Why is it necessary? Write the formula for the maximum safe velocity on a banked road.
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42.
What is a Pseudo Force? Under what condition does it act?
5. Work, Energy and Power
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43.
Define Work Done. Write its dot product formula, SI Unit, and Dimensional Formula. Is it a scalar or vector quantity?
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44.
Explain the conditions under which Work Done is:
a) Positive
b) Negative
c) Zero (Give examples for each) -
45.
Define Energy. Explain Kinetic Energy and Potential Energy. Write their formulas, SI Units, and Dimensional Formulas.
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46.
State the Work-Energy Theorem. Write its mathematical equation.
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47.
Distinguish between Conservative Forces and Non-Conservative Forces. Give two examples of each.
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48.
State the Law of Conservation of Mechanical Energy. Write the mathematical condition for it.
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49.
State the general Law of Conservation of Energy.
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50.
Define Power. Write its formula, SI Unit, and Dimensional Formula. Define 1 Horse Power (HP) and its relation to Watt.
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51.
Define Collision. Explain the following types based on direction:
a) Head-on Collision (1D)
b) Oblique Collision (2D) -
52.
Distinguish between the following types of collision based on Kinetic Energy:
a) Perfectly Elastic Collision
b) Inelastic Collision
c) Perfectly Inelastic Collision -
53.
State Newton's Law of Collision. Define Coefficient of Restitution (e). Write its values for Elastic, Inelastic, and Perfectly Inelastic collisions.
6. System of Particles and Rotational Motion
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54.
Define Rigid Body. What is the condition for a body to be rigid?
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55.
Explain the following types of motion for a rigid body:
a) Rectilinear Motion
b) Translational Motion
c) Circular Motion
d) Rotational Motion
e) Oscillatory Motion
f) Vibrational Motion -
56.
Define Centre of Mass. List the important properties or characteristics of Centre of Mass.
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57.
Define Centre of Gravity. How does it differ from Centre of Mass?
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58.
Define Torque (Moment of Force). Write its formula, SI Unit, and Dimensional Formula. Is it a vector?
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59.
Define Angular Momentum. Write its formula in terms of linear momentum, SI Unit, and Dimensional Formula. Write the relation between Torque and Angular Momentum.
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60.
State the Principle of Conservation of Angular Momentum. Give one example.
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61.
Define Moment of Inertia. Write its mathematical formula, SI Unit, and Dimensional Formula.
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62.
Define Radius of Gyration. Write its formula and SI Unit.
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63.
State the Theorem of Perpendicular Axes and the Theorem of Parallel Axes for Moment of Inertia.
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64.
Define Rolling Motion. Explain it as a combination of translation and rotation.
7. Gravitation
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65.
State Kepler's Laws of Planetary Motion:
a) Law of Orbits
b) Law of Areas
c) Law of Periods (Write the mathematical relation) -
66.
State Newton's Law of Universal Gravitation. Write its mathematical formula and vector form. List the important Characteristics of Gravitational Force.
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67.
Define Acceleration due to Gravity (\(g\)). Write its formula on the surface of the Earth. What is its SI Unit and Dimensional Formula?
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68.
Define Inertial Mass and Gravitational Mass. Write their formulas. How are they related?
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69.
Discuss the Variation of Acceleration due to Gravity (\(g\)) with:
a) Altitude (Height)
b) Depth
c) Shape of Earth
d) Rotation of Earth -
70.
Define Gravitational Field and Gravitational Field Intensity. Write the formula, SI Unit, and Dimensional Formula.
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71.
Define Gravitational Potential and Gravitational Potential Energy. Write their formulas. Are they scalar or vector quantities?
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72.
Define Escape Speed. Write its formula for Earth. What is its approximate value on Earth's surface?
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73.
Define Satellite. Write the formulas for:
a) Orbital Velocity of a satellite.
b) Time Period of Revolution of a satellite. -
74.
Write the formulas for the following energies of a satellite in orbit:
a) Kinetic Energy
b) Potential Energy
c) Total Energy (Mechanical Energy) -
75.
Define Geostationary Satellite and Polar Satellite. Write their essential conditions and uses.
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76.
What is Weightlessness in a satellite? Explain the condition under which an astronaut feels weightless.
8. Mechanical Properties of Solids
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77.
Define Plasticity. Distinguish between the following types of solids:
a) Perfectly Elastic Solids
b) Inelastic (Plastic) Solids
c) Partially Elastic Solids -
78.
Define Stress. Write its formula, SI Unit, and Dimensional Formula.
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79.
Explain the following types of Stress:
a) Longitudinal Stress (Tensile & Compressive)
b) Volumetric (Hydraulic) Stress
c) Shearing (Tangential) Stress -
80.
Define Strain. Why is it a dimensionless quantity? Explain its types:
a) Longitudinal Strain
b) Volumetric Strain
c) Shearing Strain -
81.
State Hooke's Law. Define Modulus of Elasticity.
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82.
Draw the Stress-Strain Curve for a metallic wire. Define the terms:
a) Proportional Limit
b) Elastic Limit (Yield Point)
c) Permanent Set
d) Fracture Point -
83.
What are Elastomers? Give two examples. How does their stress-strain curve differ from metals?
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84.
Define Young's Modulus of Elasticity (Y). Write its formula, SI Unit, and Dimensional Formula.
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85.
Define Bulk Modulus of Elasticity (B). Write its formula and SI Unit. What is Compressibility?
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86.
Define Shear Modulus (Modulus of Rigidity, G). Write its formula and SI Unit.
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87.
Write the formula for Elastic Potential Energy stored in a stretched wire. Express it in terms of stress and strain.
9. Mechanical Properties of Fluids
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88.
Define Thrust and Pressure. Write their formulas, SI Units, and Dimensional Formulas.
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89.
Distinguish between the following types of pressure:
a) Atmospheric Pressure
b) Gauge Pressure
c) Absolute Pressure -
90.
State Pascal's Law of transmission of fluid pressure.
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91.
Define Density. Write its formula, SI Unit, and Dimensional Formula.
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92.
Distinguish between Streamline Flow and Turbulent Flow.
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93.
State Bernoulli's Principle. Write its mathematical equation.
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94.
Explain the following applications of Bernoulli's Principle:
a) Dynamic Lift of an Aeroplane
b) Magnus Effect (Spinning Ball)
c) Venturimeter -
95.
State Torricelli's Theorem. Write the formula for the Velocity of Efflux.
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96.
Define Viscosity. Define Coefficient of Viscosity and Velocity Gradient. Write their units.
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97.
State Stokes' Law. Write the formula for viscous drag force. What is its importance?
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98.
Define Terminal Velocity. Write its formula. Define Critical Velocity.
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99.
Define Surface Tension. Write its formula, SI Unit, and Dimensional Formula. Give one example.
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100.
Define Surface Energy. Define Angle of Contact.
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101.
What is Capillarity (Capillary Action)? Write the formula for capillary rise. How does Detergent affect Surface Tension?
10. Thermal Properties of Matter
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102.
Define Heat and Temperature. Distinguish between them. Write their SI Units and Dimensional Formulas.
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103.
State the principle of a Thermometer. Write the conversion formulas between Celsius, Fahrenheit, and Kelvin scales.
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104.
State the following Gas Laws:
a) Boyle's Law
b) Charles's Law
c) Gay Lussac's Law
d) Avogadro's Law -
105.
Write the Ideal Gas Equation. Define the Universal Gas Constant (R). Write its SI Unit and Dimensional Formula.
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106.
Define Absolute Temperature (Absolute Zero). What are the values of temperature and pressure at NTP and STP?
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107.
Define Thermal Expansion. Explain the following types with their formulas:
a) Linear Expansion (\(\alpha\))
b) Superficial Expansion (\(\beta\))
c) Cubical Expansion (\(\gamma\)) -
108.
What is the Anomalous Behaviour of Water? Write the relation between the coefficients \(\alpha\), \(\beta\), and \(\gamma\).
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109.
What is Thermal Stress? Write its formula.
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110.
Define Specific Heat Capacity and Molar Specific Heat Capacity. Write their formulas, SI Units, and Dimensional Formulas.
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111.
Define Latent Heat (Hidden Heat). Write its formula, SI Unit, and Dimensional Formula.
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112.
Define the following terms related to Change of State:
a) Melting Point & Freezing Point
b) Boiling Point & Condensation
c) Sublimation & Evaporation
d) Triple Point -
113.
Explain the three modes of Heat Transfer: Conduction, Convection, and Radiation.
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114.
Define Thermal Conductivity. Write its formula, SI Unit, and Dimensional Formula.
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115.
Define the properties of Thermal Radiation:
a) Reflectance (Reflective Power)
b) Absorptance (Absorptive Power)
c) Transmittance (Transmittive Power) -
116.
Define Emissive Power and Emissivity. What is a Black Body?
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117.
State Kirchhoff's Law of thermal radiation.
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118.
State Stefan's Law (Stefan-Boltzmann Law). Write its mathematical formula. Write the SI Unit of Stefan's Constant (\(\sigma\)).
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119.
State Wien's Displacement Law. Write its formula. Write the SI Unit of Wien's Constant (\(b\)).
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120.
State Newton's Law of Cooling. Write its mathematical expression.
11. Thermodynamics
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121.
Define Thermodynamics. What is meant by Thermal Equilibrium? State the Zeroth Law of Thermodynamics.
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122.
Define Internal Energy. Write the formula for Work Done in thermodynamics. Is work a state function or a path function?
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123.
State the First Law of Thermodynamics. Write its mathematical expression (\( \Delta Q = \Delta U + \Delta W \)). List its limitations.
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124.
Define the following Thermodynamic Processes:
a) Isothermal Process
b) Isobaric Process
c) Isochoric Process
d) Adiabatic Process
e) Polytropic Process -
125.
Write the relations between \(P, V,\) and \(T\) for an Adiabatic Process involving an ideal gas (e.g., \(PV^\gamma = \text{constant}\)).
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126.
What is a Cyclic Process? What is the change in Internal Energy in a cyclic process? How is the Work Done calculated from a P-V diagram?
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127.
State the Second Law of Thermodynamics according to:
a) Kelvin-Planck Statement
b) Clausius Statement -
128.
Distinguish between Reversible and Irreversible Processes. Give two examples of each.
12. Kinetic Theory of Gases
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129.
Write the Ideal Gas Equation (Perfect Gas Equation). State Dalton's Law of Partial Pressures.
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130.
Write the main Assumptions of the Kinetic Theory of Gases.
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131.
Define Degrees of Freedom. How many degrees of freedom does a monoatomic, diatomic, and triatomic gas molecule have?
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132.
State the Law of Equipartition of Energy. What is the energy associated with each degree of freedom per molecule?
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133.
Define Molar Specific Heat Capacity at:
a) Constant Volume (\(C_v\))
b) Constant Pressure (\(C_p\))
Write the relation between them (Mayer's Formula). -
134.
Define Mean Free Path. Write its formula. On what factors does it depend?
13. Oscillations
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135.
Define Oscillatory (Vibratory) Motion and Periodic Motion. Give one example of each. Is every oscillatory motion periodic?
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136.
Define Time Period and Frequency. Write their mathematical relation, SI Units, and Dimensional Formulas.
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137.
Define Simple Harmonic Motion (SHM). Explain how SHM is related to Uniform Circular Motion.
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138.
Define Restoring Force. Write its formula for a spring-mass system. Write its SI Unit and Dimensional Formula.
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139.
Distinguish between Damped Oscillations and Undamped Oscillations.
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140.
What are Forced Oscillations? Define Resonance (Resonant Vibration). What is the condition for resonance to occur?
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141.
Write the expression for the Time Period of a Simple Pendulum. On what factors does it depend?
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142.
Write the formula for the Potential Energy, Kinetic Energy, and Total Energy of a particle executing SHM.
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143.
What is the Phase of a vibrating particle? What is the phase difference between velocity and displacement in SHM?
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144.
Define Spring Constant (Force Constant). Write its formula, SI unit, and dimensional formula.
14. Waves
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145.
Define a Wave. Classify waves on the basis of vibration of particles into Transverse and Longitudinal waves. Give one example of each.
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146.
Classify waves on the basis of medium:
a) Mechanical Waves (Elastic Waves)
b) Non-Mechanical Waves (Electromagnetic Waves)
Give two examples of each. -
147.
Classify waves on the basis of dimensions (1D, 2D, and 3D). Give an example for each type.
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148.
Define the following components of a wave. Write their SI Units and Dimensional Formulas:
a) Amplitude (A)
b) Time Period (T)
c) Frequency (\(\nu\)) -
149.
Define the following terms. Write their formulas, SI Units, and Dimensional Formulas:
a) Wavelength (\(\lambda\))
b) Wave Number (\(\bar{\nu}\))
c) Angular Wave Number (Propagation Constant, \(k\)) -
150.
Define Wave Velocity (Phase Velocity) and Angular Frequency (\(\omega\)). Write the relation between Wave Velocity, Frequency, and Wavelength.
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151.
Write the general equation of a Plane Progressive Wave traveling in the positive x-direction. Explain each term in the equation.
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152.
Distinguish between Progressive Waves and Stationary (Standing) Waves.
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153.
Define Beats. What is Beat Frequency? Write the formula for beat frequency in terms of individual frequencies.
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154.
What are Nodes and Antinodes in a stationary wave? What is the distance between two consecutive nodes?