Question

The sun radiates electromagnetic energy at the rate of $3.9\times {10}^{26}W$ . Its radius is $6.96\times {10}^{8}m.$ The intensity of sun light at the solar surface will be in $\left(\frac{W}{m^2}\right)$

• A. $1.4\times {10}^4$
• B. $2.8\times {10}^5$
• C. $64\times {10}^6$
• D. $5.6\times {10}^7$

Answer 1

The correct option is C $64\times {10}^6$

Given,

$\begin{array}{c}E=3.9\times {10}^{26}W\\ R_0=6.96\times {10}^{8}m\end{array}$

Total $l$ solar energy sector is radius $R_0$.

$\begin{array}{c}R=Js,wheres-squareofsun\\ S=4\pi {R^2}_0,thenJ=\frac{E}{4\pi {R^2}_0}\\ J=\frac{3.9\times {10}^{26}W}{4.\pi .{\left(6.96\times {10}^{8}m\right)}^2}\\ =\frac{3.9\times {10}^{26}W}{6.08\times {10}^{18}{m}^2}\approx 6.4\times {10}^7\frac{W}{m^2}\end{array}$

The intensity of radiation from the solar.

$J=6.4\times {10}^7\frac{W}{m^2}$