A light emitting diode (L.E.D.) emits photons with an energy of
$5.315 \times 10 ^ { - 19 }$
J. What is the energy per mole of photons emitted? ?
A) $3.201 \times 10 ^ { 5 }$ J/mol
B) $8.826 \times 10 ^ { 0 }$ J/mol
C) $3.201 \times 10 ^ { 8 }$ J/mol
D) $5.315 \times 10 ^ { - 19 }$ J/mol
E) $8.826 \times 10 ^ { 6 }$ J/mol

Question

A light emitting diode (L.E.D.) emits photons with an energy of 
$5.315 \times 10 ^ { - 19 }$
J. What is the energy per mole of photons emitted? ?
A) $3.201 \times 10 ^ { 5 }$ J/mol
B) $8.826 \times 10 ^ { 0 }$ J/mol
C) $3.201 \times 10 ^ { 8 }$ J/mol
D) $5.315 \times 10 ^ { - 19 }$ J/mol
E) $8.826 \times 10 ^ { 6 }$ J/mol

Quizplus · Accepted Answer

The energy per mole of photons is given by the product of the energy of a single photon and Avogadro's number:$$E_{mol} = N_A 	imes E_{photon}$$$$E_{mol} = (6.022 	imes 10^{23} 	ext{ mol}^{-1}) 	imes (5.315 	imes 10^{-19} 	ext{ J})$$$$E_{mol} = 3.201 	imes 10^5 	ext{ J/mol}$$

A Light Emitting Diode (L 5.315×10−195.315 \times 10 ^ { - 19 }5.315×10−19

A Light Emitting Diode (L $5.315 \times 10 ^ { - 19 }$