Question

What is the energy of an electromagnetic wave that has a wavelength of
7.0 x 10-12 m? Use the equation E= hc where hc = 1.99 × 10-25 J-m.
OA. 2.8 × 10-14 J
OB. 1.4 x 10-36 J
OC. 9.0 x 10-37 J
OD. 7.2 x 1035 J
SUBMIT

Answer 1

${\qquad\qquad\huge\underline{{\sf Answer}}}$

Here we go ~

$\qquad \sf  \dashrightarrow \:E = \dfrac{hc}{\lambda}$

here,

• $\sf{hc = 1.99 × {10}^{-25} J - m}$

• $\sf{\lambda = 7.0 × {10}^{-12}}$

____________________________________

$\qquad \sf  \dashrightarrow \: E = \cfrac{1.99 \times 10 {}^{ - 25} }{7 \times 10 {}^{ - 12} }$

$\qquad \sf  \dashrightarrow \: E= \cfrac{1.99}{7} \times 10 {}^{ (- 25 + 12)} { }$

$\qquad \sf  \dashrightarrow \:E= 0.284 \times 10 { }^{ - 13}$

$\qquad \sf  \dashrightarrow \: E= 2.84 \times 10 { }^{ - 14\:\; } J\: \:$

so, correct choice is A