Question

The luminous intensity of 100 W unidirectional bulb is 100 candela. The total luminous flux emitted from bulb will be(a) 100 π lumen(b) 200 π lumen(c) 300 π lumen(d) 400 π lumen

Answer 1

The luminous intensity of 100 W unidirectional bulb is 100 candela. The total luminous flux emitted from bulb will be(a) 100 π lumen(b) 200 π lumen(c) 300 π lumen(d) 400 π lumen?


correct answer:-'C'

Answer 2

Answer:

(d) 400 π lumen is the correct answer.

Explanation:

Luminous intensity in the direction of the come is the ratio of flux dF to the solid angle dw.

It may also be defined as flux emitted by the source oer unit solid angle.

I is respresnted as the luminous intensity.

I= dF/dw

Lumen is the unit of flux.

It is defined as the luminous flux per unit angle form a source of 1 candle power.

Lumens = candle power* solid angle.

= CP*w

The tidal flux emiiyed by the source of candle power is 4π lumens.

Given data:

Luminous intensity I = 100 candela

Power = 100 watt

To find

Luminous flux that us lumens

Lumen= candle power * solid angle

= 4π*w

= 4π*100

=400π lumens

Hence,

(d) 400 π lumen is the correct answer.