A source of monochromatic radiation wavelength 400 nm provides 1000 J of energy in 10 seconds. When this radiation falls on the surface of sodium, x × 10 20 electrons are ejected per second. Assume th

Question

A source of monochromatic radiation wavelength $400 nm$ provides $1000 J$ of energy in $10$ seconds. When this radiation falls on the surface of sodium, $x \times 10^{20}$ electrons are ejected per second. Assume that wavelength $400 nm$ is sufficient for ejection of electron from the surface of sodium metal. The value of $x$ is ______. (Nearest integer)

$(h = 6.626 \times 10^{- 34} Js)$

TestHub · Accepted Answer

Total energy provided by

Source per second $= \frac{1000}{10} = 100 J$

Energy required to eject electron $= \frac{hc}{λ}$

$= \frac{6.626 \times 10^{- 34}}{400 \times 10^{- 9}} \times 3 \times 10^{8}$

Number of electrons ejected

$= \frac{100}{\frac{6.626 \times 10^{- 34} \times 3 \times 10^{8}}{400 \times 10^{- 9}}}$

$= \frac{400 \times 10^{- 7} \times 10^{26}}{6.626 \times 3}$

$= \frac{40 \times 10^{- 20}}{6.626 \times 3}$

$= 2.01 \times 10^{20}$

Chemistry - Atomic Structure Question with Solution | TestHub

Doubts & Discussion