Reference no: EM132611993

Question 1. The beam of laser propagates as a parallel beam for a distance of about
a) d^2/λ
b) d/λ
c) d^4/λ
d) d^3/λ

Question 2. The monochromatic conventional source of light has a frequency spread over the range of
a) thousand Hertz
b) hundred Mega hertz
c) thousand Mega hertz
d) hundred of hertz

Question 3. The time during which the number of atoms in a given excited state diminishes to times of its initial value is acalled the life time of the excited state.
a) 1/e
b) 1/e²
c) 1/e³
d) 1/e⁴

Question 4. The probability per unit time that the atoms are excited to upper state is called as .
a) absorption rate
b) pumping rate
c) excitation rate
d) threshold rate

Question 5. A resonator having no active medioum is called resonator.

a) active
b) passive
c) electromagnetic
d) open

Question 6. The longitudinal modes of resonator are also known as .
a) TEM modes
b) TE modes
c) parallel
d) axial modes

Question 7. Holography was invented by
a) Denisyuk
b) Leith
c) Gabor
d) Upatnicks

Question 8. In aHe-Ne laser the ratio of He to Ne is
a) 1:10
b) 10: 1
c) 10:2
d) 2:10

Question 9. The correlation between field at a point and field at the same point certain time later is called
a) spatial coherence
b) temporal coherence
c) non coherent
d) partially coherent

Question 10. The degree of non-monochromacity is related to the
a) Rayleigh length
b) coherence length
c) bandwidth
d) coherence time