Energy full set

How do you calculate efficiency?

Efficiency = Useful energy output / Total energy input.

What is the unit for efficiency?

Efficiency is a percentage or a decimal value between 0 and 1.

How do you calculate efficiency?

Efficiency = Useful energy output / Total energy input.

What is the unit for efficiency?

Efficiency is a percentage or a decimal value between 0 and 1.

Why is it important to improve efficiency in machines?

To reduce energy waste and lower energy costs.

What type of energy loss occurs in an electric motor?

Energy is lost as heat due to resistance in wires and friction.

How does insulation improve efficiency?

Insulation reduces the rate of energy loss through conduction.

What is the effect of friction on efficiency?

It reduces efficiency by converting useful energy into heat.

What is the main source of inefficiency in a car engine?

Friction in moving parts and heat loss.

How can efficiency be increased in power plants?

By using combined heat and power (CHP) systems, reducing waste heat.

What is a renewable energy source?

A source of energy that replenishes itself naturally, like wind or solar.

How does reducing energy loss impact the environment?

Reducing energy loss lowers fuel consumption and emissions, reducing environmental impact.

What is energy efficiency?

Energy efficiency is the measure of how much input energy is converted into useful output energy.

What is the formula for calculating energy efficiency?

Efficiency = (Useful energy output / Total energy input) * 100%

What factors can reduce energy efficiency in machines?

Friction, air resistance, and heat loss are factors that can reduce energy efficiency.

What is meant by a "wasted energy" in a system?

Wasted energy is energy that is not useful and is often lost as heat or sound.

What are some ways to improve energy efficiency in a system?

Reducing friction, improving insulation, and using more efficient components can improve efficiency.

What is the relationship between power and efficiency?

Power is the rate at which energy is transferred or converted, and efficiency measures how much of that power is usefully applied.

How does a more efficient car engine work?

A more efficient car engine converts more fuel energy into useful work and less into wasted heat.

What is a real-life example of a device with high efficiency?

LED light bulbs, which convert most of the electrical energy into light rather than heat.

Why is it important to increase energy efficiency in homes?

Improving energy efficiency in homes can reduce energy costs and environmental impact.

What is the effect of using renewable energy on efficiency?

Renewable energy sources, like solar and wind, are often more efficient and sustainable than non-renewable sources.

What is kinetic energy?

Kinetic energy is the energy of an object due to its motion.

What is the formula for kinetic energy?

Kinetic Energy = 0.5 Mass Velocity² (KE = 0.5 m v²).

What is the unit for kinetic energy?

The unit for kinetic energy is joules (J).

What factors affect the kinetic energy of an object?

Kinetic energy is affected by the mass and velocity of the object.

What is gravitational potential energy?

Gravitational potential energy is the energy stored in an object due to its position in a gravitational field.

What is the formula for gravitational potential energy?

Gravitational Potential Energy = Mass Gravitational field strength Height (GPE = m g h).

What is the unit for gravitational potential energy?

The unit for gravitational potential energy is joules (J).

How does an object’s height affect its gravitational potential energy?

The higher the object, the greater its gravitational potential energy.

How is gravitational potential energy converted to kinetic energy?

As an object falls, its gravitational potential energy is converted to kinetic energy.

What is the law of conservation of energy?

Energy cannot be created or destroyed; it can only be transformed from one form to another.

What are the different types of energy transfer?

Heating, mechanical work, electrical work, radiation.

How is energy transferred when a person lifts an object?

Work is done against gravity, transferring energy from the person's muscles to gravitational potential energy.

What is the relationship between power and energy transfer?

Power = Energy transferred / Time.

How does energy transfer in a toaster?

Electrical energy is transferred to thermal energy due to resistance.

What type of energy transfer occurs when a pan is heated on a stove?

Thermal energy is transferred by conduction.

What is conduction?

The transfer of heat through a material without the movement of the material itself.

What is convection?

The transfer of heat by the movement of fluid (liquids or gases).

What is radiation?

The transfer of energy through electromagnetic waves (no medium required).

How is energy transferred in the form of light?

Electromagnetic waves transfer energy through space.

What is the role of an insulating material?

Reduces energy loss by reducing heat transfer through conduction, convection, and radiation.

What is meant by energy transfer?

Energy transfer is the process of energy moving from one place or object to another.

What are the types of energy transfers?

The types include mechanical, thermal, electrical, light, and sound energy.

How is energy transferred by conduction?

Conduction transfers energy through a material when particles vibrate and pass on their energy to neighboring particles.

How is energy transferred by convection?

Convection transfers heat in liquids and gases as warmer, less dense regions rise and cooler, denser regions sink.

How is energy transferred by radiation?

Radiation transfers energy through electromagnetic waves, such as light and infrared.

What is the role of a thermos flask in preventing energy transfer?

A thermos flask minimizes energy transfer by conduction, convection, and radiation.

What is an example of energy transfer in a toaster?

In a toaster, electrical energy is converted to thermal energy by resistance heating.

How does insulation reduce energy loss in homes?

Insulation reduces energy transfer by conduction, convection, and radiation.

What is the difference between energy transfer and energy transformation?

Energy transfer moves energy from one object or location to another; transformation changes energy from one form to another.

How does a heat pump transfer thermal energy?

A heat pump transfers thermal energy from a cooler area to a warmer area using mechanical work.

What is work done in physics?

Work done = Force Distance moved in the direction of the force (W = F d).

What is the unit for work done?

Joules (J).

How do you calculate power?

Power = Work done / Time (P = W / t).

What is the unit for power?

Watts (W), where 1 watt = 1 joule per second.

If a force of 10 N is applied to move an object 5 meters, how much work is done?

Work done = 10 N * 5 m = 50 J.

How is power related to energy transfer?

Power is the rate at which energy is transferred or converted.

What is the formula for calculating work done when an object is lifted?

Work done = Force Distance (Force = weight = mass gravitational field strength).

What is meant by efficiency in terms of power?

Efficiency refers to the ratio of useful energy output to total energy input.

How do you calculate the power of an electric heater if it transfers 1000 J of energy in 10 seconds?

Power = 1000 J / 10 s = 100 W.

What happens to power if the time taken to do a task is reduced while keeping work constant?

The power increases.

What are the different types of energy resources?

Fossil fuels, nuclear, wind, solar, geothermal, biomass, hydroelectric.

What is a renewable energy resource?

A resource that is naturally replenished, such as solar or wind energy.

What is a non-renewable energy resource?

A resource that cannot be replenished within a human lifetime, such as coal or oil.

What are the advantages of using renewable energy sources?

They are sustainable, produce little to no pollution, and are not depleting.

What are the disadvantages of using renewable energy sources?

They can be expensive to set up, depend on weather conditions, and have limited availability.

How does solar energy work?

Solar panels convert sunlight directly into electricity using photovoltaic cells.

What is the environmental impact of burning fossil fuels?

It releases carbon dioxide, contributing to climate change.

What is the principle behind nuclear energy generation?

Nuclear fission produces energy by splitting atoms, releasing large amounts of energy.

What is the main disadvantage of nuclear energy?

It produces radioactive waste, which is difficult and dangerous to store.

What are biofuels, and how are they used?

Biofuels are derived from organic materials and are used as alternatives to fossil fuels for energy generation.

What is the law of conservation of energy?

Energy cannot be created or destroyed, only transformed or transferred.

How does energy conservation apply to a falling object?

The potential energy is converted to kinetic energy.

What happens to energy in a frictional force?

Some energy is lost as heat, reducing the mechanical energy.

How can energy be conserved in a car engine?

By reducing friction, using efficient materials, and transferring energy more efficiently.

How is energy conserved when you stop a car?

Kinetic energy is converted to thermal energy due to friction in the brakes.

How does energy conservation apply to a rollercoaster?

Potential energy at the top is converted to kinetic energy as it descends.

How does energy transfer during a bouncing ball?

Kinetic energy is converted to potential energy at the highest point, and vice versa.

What is an energy chain?

The sequence of energy transfers between different stores.

Why is it impossible to achieve 100% efficiency in machines?

Some energy is always lost as heat due to friction and other inefficiencies.

How does a battery-powered device conserve energy?

Electrical energy from the battery is converted into other forms of energy, like light or sound.

What are the main types of energy stores?

Kinetic, thermal, chemical, gravitational potential, elastic potential, nuclear, internal.

Define energy transfer.

The movement of energy from one place to another (e.g., mechanical, electrical).

How is energy transferred in a lamp?

Electrical energy is transferred into light and heat energy.

What is an energy system?

A collection of energy stores and energy transfers.

How do you calculate energy in the kinetic energy store?

KE = 0.5 mass velocity² (Joules).

What is an example of a closed system?

A thermos flask (energy does not enter or leave the system).

Which energy store is involved in a stretched rubber band?

Elastic potential energy.

What is meant by the conservation of energy?

Energy cannot be created or destroyed, only transferred or transformed.

How is energy lost in a car engine?

As thermal energy due to friction and inefficiencies.

What is the unit for energy?

Joules (J).