Physics

• Energy can be transferred from one object to another by work done or heat transfer.
• The SI unit of energy is the joule (J).
• Work done = force x distance moved in direction of force
• Power is defined as the rate at which energy is used, stored, or transferred.
• Work is the energy transferred when a force moves an object through a distance, with units of joules (J).
• Heat is the energy transferred between objects due to temperature difference, measured in joules per second (W) or kilowatt-hours (kWh).
• Average power = total energy / time taken
• The SI unit of power is watt (W), where 1 W = 1 J/s.
• The equation for calculating power is P = W/t, where P is power, W is work done, and t is time taken.
• The formula for power is P = E/t, where P is power, E is energy, and t is time.
• Thermal efficiency is calculated using the formula: thermal efficiency = useful output / total input * 100%.
• Instantaneous power = change in energy / change in time
• Heat is the energy transferred between objects due to temperature difference, measured in joules (J) or calories (cal).
• Average power is calculated using the formula: average power = total energy transferred / time taken.
• Kinetic energy is the energy possessed by an object due to its motion, calculated using the formula KE = 1/2 mv^2.
• Energy can be transformed from one form to another without being destroyed.
• Potential energy is the energy that an object has because of its position or shape, such as gravitational potential energy (GPE), elastic potential energy (EPE), chemical potential energy (CPE), nuclear potential energy (NPE), and thermal energy (TE).
• Conservation of energy states that the total amount of energy in any system remains constant over time.
• Conservation of energy states that the sum of all energies in a system remains constant during any process.
• Kinetic energy is the energy possessed by an object due to its motion, while potential energy is the energy stored within an object due to its position or shape.
• In a closed system, energy cannot enter or leave, so it must remain constant.
• Thermal energy is the kinetic energy of particles within an object, with higher temperatures resulting in more rapid particle movement and increased TE.
• Power can be calculated using the formula P = Fd cosθ, where F is force, d is displacement, and θ is angle between force and displacement.
• Increasing the mass flow rate increases the amount of heat transfer by conduction.
• Efficiency can be expressed as a percentage or decimal fraction.
• Energy can be transformed from one form to another without being destroyed.
• The slope of the position time graph of an object moving with negative velocity is

  Negative
• If the speed of sound changes due to temperature variation, it affects the frequency of sound waves.
• A body at rest will remain at rest unless acted upon by a resultant force.
• When two objects collide, their velocities change but momentum remains constant.
• The spring force is a

  Conservative force
• Which of the following is/are the law(s) of reflection?

  The angle of reflection is equal to the angle of incidence. The incident ray, reflected ray and the normal at the point of incidence lie on the same plane.
• In a simple pendulum, the period of oscillation depends only on the length of the string or wire and not on its mass.
• Light from a star spreads out and weakens
• Gaps do not form between photons as light spreads out
• A fire can have a shadow
• Air cannot make shadows
• Gold cannot be created from other elements
• Light can bend around corners
• Momentum cannot be hidden to human eyes like kinetic energy can be hidden as heat