Light with an average flux of 20 Ω/cm2 falls on a non-reflecting surface at normal incidence having surface area 20 cm2. The energy received by the surface during time span of 1 minute is :

Question

Light with an average flux of 20 Ω/cm2 falls on a non-reflecting surface at normal incidence having surface area 20 cm2. The energy received by the surface during time span of 1 minute is : (A) 10 × 103J (B) 12 × 103J (C) 24 × 103J (D) 48 × 103J

Tardigrade Admin · Accepted Answer

Energy received = Intensity × Area × Time I=(E/A) E=IAt =(20/10-4)× 20× 10-4× 60 =24 × 103 J

Q. Light with an average flux of $20 Ω/ c m^{2}$ falls on a non-reflecting surface at normal incidence having surface area $20 c m^{2}$ . The energy received by the surface during time span of $1 min u t e$ is :

$10 \times 1 0^{3} J$

$12 \times 1 0^{3} J$

$24 \times 1 0^{3} J$

$48 \times 1 0^{3} J$

Energy received = Intensity $\times$ Area $\times$ Time
$I = \frac{E}{A}$
$E = I A t$
$= \frac{20}{1 0 ^{- 4}} \times 20 \times 1 0^{- 4} \times 60$
$= 24 \times 1 0^{3} J$

Q. Light with an average flux of 20Ω/cm2 falls on a non-reflecting surface at normal incidence having surface area 20cm2. The energy received by the surface during time span of 1minute is :

10×103J

12×103J

24×103J

48×103J