2nd Midterm 1st semester Flashcards
The shape of a water molecule resembles
A) An icosahedron
B) A cube
C) A tetrahedron
D) A pentahedron
C) tetrahedron
Which one of the following is not the property of laser light?
A) Coherent
B) Monochromatic
C) Convergent
D) Typically has high intensity
C) Convergent
Why is the sky blue?
A) Because red light is refracted more, thus mostly bluelight reaches our eyes
B) Because blue light is scattered more
C) Because the thermal radiation of the sun (equivalent to a black body of 6000K) is the most intensive in the blue wavelength interval
D) Because the light of lower photon energy (red) is absorbed more while traveling the surface, thus mostly blue light reaches our eyes
B) Because blue light is scattered more
Stimulated emission is induced by:
A) The pumping energy
B) spontaneoulsy emitted photons
C) exciting photons
D) suitably high temperature
B) Spontaneously emitted photons
Choose the wrong answer:
A) The half life time of fluorescence is longer than that of phosphorescence.
B) Phosphorescence is spontanseous photon emission from a metastable level.
C)The emission spectrum of Phosphorescence is shrifted towards lesser photon energies relative to that of fluorescence.
D) Fluorescence is spontaneous photon emission from permitted electron transition
A) The half life time of fluorescence is longer than that of phosphorecence
How do we decompose the light in a manual Spectroscope
A) Mirror
B) Prisms
C) Optical grating
D) Lenses
B) Prisms
What is resonance?
A) When frequency of the driven oscillation increases till it reaches the value of the eigen-frequency
B) When amplitude of the oscillation increases till it reaches the amplitude of the Eigen-frequency
C) Such a driven oscillation when the driving frequency is close to the eigen frequency of the system
D) When both the amplitude and the frequency of the oscillation can have arbitrarily big values
B) Such a driven oscillation when the driving frequency is close to the eigen frequency of the system
