Question

When sunlight falls normally on Earth, a luminous flux of $1.57\times {10}^5$ lumen/$m^2$ is produced on Earth. The distance of Earth from Sun is $1.5\times {10}^8$ $km$. The luminous intensity of Sun in candela will be

• A. $3.53\times {10}^{27}$
• B. $3.53\times {10}^{25}$
• C. $3.53\times {10}^{29}$
• D. $3.53\times {10}^{21}$

Answer 1

Answer: (A)

$3.53\times {10}^{27}$

Luminous flux,$I=1.57\times {10}^{5}lumen/m^2$

Distance, $d=1.5\times {10}^{8}Km=1.5\times {10}^{11}m$

Luminous intensity of sun = $I\times d^2$

= $1.57\times {10}^5\times (1.5\times {10}^{11}{)}^2$

= $3.53\times {10}^{27}$

Answer. A) $3.53\times {10}^{27}$