Question

os comprimentos de onda da radiação visivel estão compreendidos entre 400 e 700 manómetros.qual é ,em Hz, o intervalo de frequência correspondente? (C=300.000km/s)

A-1,2.10¹⁴ e 2,2.10¹⁴
B-2,3.10¹⁴ e 3,3.10¹⁴
C-7,5.10¹⁴ e 4,3.10¹⁴
D-8,5.10¹⁴ e 9,5.10¹⁴

Answer 1

Resp.: A faixa de frequência para os comprimentos de ondas dados é de $4,28\cdot10^{14}~Hz$ a $7,5\cdot10^{14}$ Letra C.

$\boxed{\boxed{f=\frac{C}{\lambda}}}\bigstar\\\\f_1=\frac{3\cdot10^8}{400\cdot10^{-9}}\\\\f_1=\frac{3\cdot10^{8-(-9)}}{400}\\\\f_1=\frac{3\cdot10^{8+9}}{400}\\\\f_1=\frac{3\cdot10^{17}}{400}\\\\f_1=\frac{3\cdot100000000000000000\div400}{400\div400}\\\\f_1=3\cdot250000000000000\\\\f_1=750000000000000\\\\\boxed{f_1=7,5\cdot10^{14}}\checkmark$

$f_2=\frac{C}{\lambda}\\\\f_2=\frac{3\cdot10^{\diagup\!\!\!\!8}}{700\cdot\diagup\!\!\!\!\!\!\!10^{-9}}\\\\f_2=\frac{3\cdot10^{17}}{700}\\\\f_2=\frac{3\cdot000000000000000\diagup\!\!\!\!\!\!00}{7\diagup\!\!\!\!\!\!00}\\\\f_2=\frac{3000000000000000}{7}\\\\f_2=\frac{3}{7}\approx0,428\\\\f_2=0,428\cdot100000000000000\\\\\boxed{f_2=4,28\cdot10^{14}}\checkmark$