Correct option is B
This is in the context of two-photon microscopy vs. traditional confocal microscopy:
Statement A: True
"By using longer wavelength, two-photon microscopy induces less photobleaching of the tissue preparation."
Correct: Two-photon microscopy uses longer wavelengths (typically infrared), which have lower energy and hence cause less photodamage or photobleaching outside the focal point.
Statement B: False
"By using shorter wavelength, two-photon microscopy induces less photobleaching of the tissue preparation."
Incorrect: Two-photon microscopy uses longer, not shorter, wavelengths. Shorter wavelengths are used in traditional confocal microscopy and cause more photobleaching.
Statement C: False
"The intensity of fluorescence emitted by the sample will remain the same even if only one of the two exciting photons impinge on the sample."
Incorrect: Two-photon excitation requires two photons simultaneously; if only one photon hits, no excitation (and hence no fluorescence) occurs.
Statement D: True
"No fluorescence is detected unless two exciting photons simultaneously impinge on the sample."
Correct: This is a fundamental principle of two-photon excitation. The simultaneous absorption of two photons is necessary to excite the fluorophore.
Correct Answer: A and D (Option 2)
