Browse Definitions :
Definition

lumen

The lumen (symbolized lm) is the International Unit of luminous flux. It is defined in terms of candela steradians (cd multiplied by sr). One lumen is the amount of light emitted in a solid angle of 1 sr, from a source that radiates to an equal extent in all directions, and whose intensity is 1 cd.

One lumen is the equivalent of 1.46 milliwatt (1.46 x 10-3 W) of radiant electromagnetic (EM) power at a frequency of 540 terahertz (540 THz or 5.40 x 1014 Hz). Reduced to SI base units, one lumen is equal to 0.00146 kilogram meter squared per second cubed (1.46 x 10-3 kg multiplied by m2 / s3).

The lumen is a small unit. An electromagnetic field power level of 1.46 milliwatt is small; the radio-frequency (RF) output of a children's toy two-way radio is several times that much. A frequency of 540 THz corresponds to a wavelength of about 556 nanometers (nm), which is in the middle of the visible-light spectrum. A steradian is the standard unit solid angle in three dimensions; a sphere encloses 4 pi (approximately 12.57) steradians.

Also see candela, steradian, and International System of Units (SI).

This was last updated in September 2005
SearchCompliance
  • OPSEC (operations security)

    OPSEC (operations security) is a security and risk management process and strategy that classifies information, then determines ...

  • smart contract

    A smart contract is a decentralized application that executes business logic in response to events.

  • compliance risk

    Compliance risk is an organization's potential exposure to legal penalties, financial forfeiture and material loss, resulting ...

SearchSecurity
  • What is cybersecurity?

    Cybersecurity is the protection of internet-connected systems such as hardware, software and data from cyberthreats.

  • private key

    A private key, also known as a secret key, is a variable in cryptography that is used with an algorithm to encrypt and decrypt ...

  • DOS (disk operating system)

    A DOS, or disk operating system, is an operating system that runs from a disk drive. The term can also refer to a particular ...

SearchHealthIT
SearchDisasterRecovery
  • What is risk mitigation?

    Risk mitigation is a strategy to prepare for and lessen the effects of threats faced by a business.

  • change control

    Change control is a systematic approach to managing all changes made to a product or system.

  • disaster recovery (DR)

    Disaster recovery (DR) is an organization's ability to respond to and recover from an event that affects business operations.

SearchStorage
  • RAM (Random Access Memory)

    RAM (Random Access Memory) is the hardware in a computing device where the operating system (OS), application programs and data ...

  • RAID 6

    RAID 6, also known as double-parity RAID, uses two parity stripes on each disk. It allows for two disk failures within the RAID ...

  • NOR flash memory

    NOR flash memory is one of two types of non-volatile storage technologies.

Close