Energy Calculaton Challenge- Frequeny and Wavelengths

Question

Question #20 What is the energy of light with a wavelength of 662 nm? [Hint: 1nm=1x10-9 m]

 

Question #21 The wavelength of green light is about 522 nm. What is the frequency of this radiation? [Hint: 1nm=1x10-9 m]

 

Question #22 What is the wavelength of a photon that has a frequency of 2.10 x 1014 Hz?

 

 

 

 

 

Question #23 A classical radio station broadcasts at 93.5 MHz (9.35 x 107 Hz). Find the wavelength of this radiation in meters.

 

 

Question #24 A classical radio station broadcasts at 93.5 MHz (9.35 x 107 Hz). Find the energy of this radiation in joules.

Answer 1

Question #21

Frequency= speed of light/wavelength = 3X10⁸ m/s/522X10^-9 m

                                                       ≈5.75X10¹⁴ rps or cps or Hz

 

Question #22

wavelength of the photon= speed of light/Frequency=3X10⁸ m/s/2.10 x 10¹⁴ Hz

                                                                           ≈1.43X10-⁶ m

                                                                           ≈1.43X10⁵ nm

 

Question #23

the wavelength of the radiation=3X10⁸ m/s/9.35 x 10⁷ Hz

                                             ≈3.21 m

 

Question #24

the energy of the radiation=6.626×10⁻³⁴  J.sX9.35  x 10⁷ Hz =6.195×10⁻²⁶ J

 

Answer 2

Q 20:

The relationship between the energy of light (E) and its wavelength (λ) is,   E= (h c)/ λ

Where h is the Plank's contant ( 6.626 x 10^-34 J.s) and 'c' is the speed of light (3x10 ⁸ m/s); wavelength (λ) = 662 nm

 

E= [ ( 6.626 x 10^-34 J.s) x(3x10 ⁸ m/s)]/ (662 nm)

= 0.03 x 10 ^-17 Joules = 3x 10 ^-19 J

 

Q21:  We know that Wavelength x Frequency = Speed of light

 

Thus,  Frequency = Speed of light /wavelength = (3x10 ⁸ m/s)/522 nm = 0.0057 x 10 ¹⁷ per s (hertz) = 5.7 x 10¹⁴ Hertz