Question

If the wave length of an electromagnetic radiation is 2000angstrom .what is the energy in ergs

Answer 1

ANSWER:

• Energy = 9.94 × 10⁻¹² ergs.

GIVEN:

• The wavelength of an electromagnetic radiation is 2000 A°.

TO FIND:

• The energy in ergs.

EXPLANATION:

$\bigstar\ \boxed{\boldsymbol{\large{\purple{E = \dfrac{hc}{\lambda}}}}}$

$\sf \implies \lambda = 2000 \ A^{ \circ} =2000 \times {10}^{ - 10} \ m$

$\sf \implies h=6.626 \times {10}^{ - 34}\ Js$

$\sf \implies c = 3 \times {10}^{8 }\ ms^{-1}$

$\sf \dashrightarrow E = \dfrac{6.626 \times {10}^{ - 34} \times 3 \times {10}^{8 } }{2000 \times {10}^{ - 10} }$

$\sf \dashrightarrow E = \dfrac{6.626 \times {10}^{ - 26} \times 3}{2\times {10}^{ - 7} }$

$\sf \dashrightarrow E = \dfrac{3.313 \times {10}^{ - 26} \times 3}{{10}^{ - 7} }$

$\sf \dashrightarrow E = 9.939\times {10}^{ - 19} \ J$

$\bigstar\ \boxed{\bold{\large{\pink{1\ joule = 10^7\ ergs}}}}$

$\sf \dashrightarrow E = 9.939\times {10}^{ - 19} \times {10}^{7} \ ergs$

$\sf \dashrightarrow E = 9.94\times {10}^{ - 12}\ ergs$

Hence the energy in ergs = 9.94 × 10⁻¹² ergs.