Answer:D
Explanation:
When the character falls off from cliff he moves away from the observer as he falls down and hence the frequency heard by observer lowers as he falls.
Therefore the pitch of the sound is lower than the original sound and decreasing as he falls
Option D is the correct choice
Answer:
the charge carriers have an energy 2.8 10⁻¹⁹ J
Explanation:
The energy in a diode is conserved so the energy supplied must be equal to the energy emitted in the form of photons.
The energy of a photon is given by the Planck expression
E = h f
the speed of light, wavelength and frequency are related
c = λ f
we substitute
E =
a red photon has a wavelength of lam = 700 nm = 700 10⁻⁹ m
we calculate the energy
E = 6.626 10⁻³⁴ 3 10⁸/700 10⁻⁹
E = 2.8397 10⁻¹⁹J
therefore the charge carriers have an energy 2.8 10⁻¹⁹ J,
They have pure elements or a verity of compounds inside.