Class

NSUnitEnergy

A unit of measure for energy.

Declaration

@interface NSUnitEnergy : NSDimension

Overview

You typically use instances of NSUnitEnergy to represent specific quantities of energy using the NSMeasurement class.

Energy

Energy is a fundamental property of matter than can be transferred and converted into different forms, such as kinetic, electric, and thermal. The SI unit for energy is the joule (J), which is derived as the work of one meter of displacement in the direction of a force of one newton (1J = 1N ∙ 1m). It can also be derived as the work required to displace an electric charge of one coulomb through an electrical potential difference of one volt (1J = 1C ∙ 1V), or the work required to produce one watt of power for one second (1J = 1W ∙ 1s). Energy is also commonly expressed in terms of the calorie (cal), or the energy needed to raise the temperature of one gram of water by one degree Celsius at a pressure of one atmosphere (1cal ≡ 4.184J).

The NSUnitEnergy class defines its base unit as joules, and provides the following units, which are initialized using NSUnitConverterLinear converters with the specified coefficients:

Name

Method

Symbol

Coefficient

Kilojoules

kilojoules

kJ

1000.0

Joules

joules

J

1.0

Kilocalories

kilocalories

kCal

4184.0

Calories

calories

cal

4.184

Kilowatt Hours

kilowattHours

kWh

3600000.0

Topics

Accessing the Base Unit

+ baseUnit

Returns the base unit of energy. Equal to joules.

Accessing Predefined Units

kilojoules

Returns the kilojoules unit of energy.

joules

Returns the joules unit of energy.

kilocalories

Returns the kilocalories unit of energy.

calories

Returns the calories unit of energy.

kilowattHours

Returns the kilowatt hour unit of energy.

Relationships

Inherits From

Conforms To

See Also

Energy, Heat, and Light

NSUnitPower

A unit of measure for power.

NSUnitTemperature

A unit of measure for temperature.

NSUnitIlluminance

A unit of measure for luminance.