Utilization of Electrical Energy : Illumination

By Vishal Singh|Updated : August 23rd, 2021

Complete coverage of syllabus is a very important aspect for any competitive examination but before that important subject and their concept must be covered thoroughly. In this article, we are going to discuss Utilization of Electrical Energy: Illumination which is very useful for SSC JE Exams

ILLUMINATION

Illumination differs from light very much. Light is the cause and illumination is the result of that light on surfaces on which it falls. Thus, the illumination makes the surface look bright with a certain color and it is this brightness and color which the eye sees and interprets as something useful, or pleasant or otherwise.

It is defined as the luminous flux (number of lumens), falling on the surface per unit area. It is measured in lumens/m2 or lux or meter candle.

Light may be produced by passing electric current through

filaments as in the incandescent lamps

arcs between carbon or metal rods

suitable gases as in neon and other gas tubes.

In some forms of lamps, the light is due to fluorescence excited by radiation arising from the passage of electric current through mercury vapour.

1.1.  Lumen-hours

Light is defined as the radiant energy from a hot body which produces visual sensation upon the human eye. It is measured in lumen-hours.

1.2.  Luminous flux

It is defined as the total quantity of light energy emitted per second from a luminous body. It is measured in lumens (or cd-sr).

1.3.  Luminous intensity

In any given direction is the luminous flux emitted by the source per unit angle, measured in the direction in which the intensity is required. It is measured in candela (cd) or lumens per steradian.

1.4.  Lumen

It is the unit of luminous flux and is defined as the amount of luminous flux given out in space represented by one unit of solid angle by a source having an intensity of one candle power in all directions. The total lumens given out by a source of one candela is 4π lumens.

1.5.  Candle power

It is the light radiating capacity of a source in each direction and is defined as the number of lumens given out by the source in a unit solid angle in each direction.

1.6.  Candela

It is the unit of luminous intensity and is defined as  th of the luminous intensity per cm2 of a black body radiator at the temperature of solidification of platinum (2,043° K).

1.7.  Lamp efficiency

It is defined as the ratio of luminous  to the power input. It is measured in lumens per watt.

You can avail of Online Classroom Program for all AE & JE Exams:

Online Classroom Program for AE & JE Exams (12+ Structured LIVE Courses and 160+ Mock Tests)

You can avail of BYJU'S Exam Prep Test Series specially designed for all AE & JE Exams:

BYJU'S Exam Prep Test Series AE & JE (160+ Mock Tests) 

Thanks, 

Team BYJU'S Exam Prep

Sahi Prep Hai to Life Set Hai !!!

Download BYJU'S Exam Prep APP , for best Exam Preparation , Free Mock Test, Live Classes

Posted by:

Vishal SinghVishal SinghMember since Jun 2021
Vishal Singh (Civil engineering) SSC JE Qualified
Share this article   |

Comments

write a comment

AE & JE Exams

AE & JERVUNLUPSSSCSDEPSPCLPPSCSSC JEGPSCTNPSCAAIDFCCILUPRVUNLPSPCLOthersPracticeMock TestCourse
tags :AE & JE ExamsNHPC JE ExamRSMSSB JE ExamGSECL JE ExamRRB JE ExamNWDA JE Exam

AE & JE Exams

AE & JERVUNLUPSSSCSDEPSPCLPPSCSSC JEGPSCTNPSCAAIDFCCILUPRVUNLPSPCLOthersPracticeMock TestCourse
tags :AE & JE ExamsNHPC JE ExamRSMSSB JE ExamGSECL JE ExamRRB JE ExamNWDA JE Exam

Follow us for latest updates