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

Start the conversation

Send me notifications when other members comment.

Please create a username to comment.

-ADS BY GOOGLE

File Extensions and File Formats

Powered by:

SearchCompliance

  • risk management

    Risk management is the process of identifying, assessing and controlling threats to an organization's capital and earnings.

  • compliance as a service (CaaS)

    Compliance as a Service (CaaS) is a cloud service service level agreement (SLA) that specified how a managed service provider (...

  • data protection impact assessment (DPIA)

    A data protection impact assessment (DPIA) is a process designed to help organizations determine how data processing systems, ...

SearchSecurity

  • identity theft

    Identity theft, also known as identity fraud, is a crime in which an imposter obtains key pieces of personally identifiable ...

  • cybercrime

    Cybercrime is any criminal activity that involves a computer, networked device or a network.

  • cybersecurity insurance (cybersecurity liability insurance)

    Cybersecurity insurance, also called cyber liability insurance or cyber insurance, is a contract that an entity can purchase to ...

SearchHealthIT

SearchDisasterRecovery

  • disaster recovery plan (DRP)

    A disaster recovery plan (DRP) is a documented, structured approach that describes how an organization can quickly resume work ...

  • business continuity plan (BCP)

    A business continuity plan (BCP) is a document that consists of the critical information an organization needs to continue ...

  • disaster recovery team

    A disaster recovery team is a group of individuals focused on planning, implementing, maintaining, auditing and testing an ...

SearchStorage

  • logical unit number (LUN)

    A logical unit number (LUN) is a unique identifier for designating an individual or collection of physical or virtual storage ...

  • NVMe over Fabrics (NVMe-oF)

    NVMe over Fabrics, also known as NVMe-oF and non-volatile memory express over fabrics, is a protocol specification designed to ...

  • CIFS (Common Internet File System)

    CIFS (Common Internet File System) is a protocol that gained popularity around the year 2000, as vendors worked to establish an ...

Close