Answer:
The observer detects light of wavelength is 115 nm.
(b) is correct option
Explanation:
Given that,
Wavelength of source = 500 nm
Velocity = 0.90 c
We need to calculate the wavelength of observer
Using Doppler effect
Where,
Hence, The observer detects light of wavelength is 115 nm.
Answer:
Volume charge density: When the charge density is throughout the volume of a body, then the charge per unit volume is called volume charge density and it is represented by ρ.
∴ρ=
Hence the unit of ρ is Cm
−3
Example: If a charge q is uniformly distributed in the whole volume of a
sphere of radius R, then p =
=3q/4πR-3
Answer:
(a) λ = 4136 nm → infrared
(b) λ = 413.6 nm → visible light
(c) λ = 41.36 nm → ultraviolet
Explanation:
The wavelength of infrared is on the range of 700 nm to 1000000 nm
The wavelength of visible light is between 400 nm and 700 nm
The wavelength of ultraviolet ray on the range of 10 nm to 400 nm
The wavelength of photon is given by;
E = hf
f is the frequency of the wave = c / λ
Where;
c is the speed of light = 3 x 10⁸ m/s
h is Planck's constant = 6.626 x 10⁻³⁴ J/s
(a) 0.3 eV = 0.3 x 1.602 x 10⁻¹⁹ J
λ = 4136 x 10⁻⁹ m
λ = 4136 nm → infrared
(b) 3.0 eV
λ = 413.6 x 10⁻⁹ m
λ = 413.6 nm →visible light
(c) 30 eV
λ = 41.36 x 10⁻⁹ m
λ = 41.36 nm →ultraviolet