1. Which part of the compound microscope helps in gathering and focusing light rays on the specimen to be viewed?
a) Eyepiece lens
b) Objective lens
c) Condenser lens
d) Magnifying lens
2. What is the minimum distance for the eye to focus any object?
a) 11 cm
b) 25 cm
c) 32 cm
d) 4 2 cm
3. Resolving power of a microscope is a function of____________
a) Wavelength of light used
b) Numerical aperture of lens system
c) Refractive index
d) Wavelength of light used and numerical aperture of lens system
4. The greatest resolution in light microscopy can be obtained with ___________
a) Longest wavelength of visible light used
b) An objective with minimum numerical aperture
c) Shortest wavelength of visible light used
d) Shortest wavelength of visible light used and an objective with the maximum numerical aperture
5. In fluorescence microscopy, which of the following performs the function of removing all light except the blue light?
a) Exciter filter
b) Barrier filter
c) Dichroic mirror
d) Mercury arc lamp
6.Total Magnification is obtained by__________
a) Magnifying power of the objective lens
b) Magnifying power of eyepiece
c) Magnifying power of condenser lens
d) Magnifying power of both the objective lens and eyepiece
7. In light microscopy, which of the following is used as fixatives prior to staining technique?
a) Osmic acid
b) Glutaraldehyde
c) Heat
d) Osmic acid, glutaraldehyde, heat
8. In Phase contrast microscopy, the rate at which light enters through objects is__________
a) Constant
b) Inversely proportional to their refractive indices
c) Directly proportional to their refractive indices
d) Exponentially related to their refractive indices
9. Which part of the light microscope controls the intensity of light entering the viewing area?
a) Coarse adjustment screw
b) Fine adjustment screw
c) Diaphragm
d) Condenser lens
10. Oil immersion objective lens has an NA value of____________
a) 0.65
b) 0.85
c) 1.33
d) 1.00
Answers
Answer:
1.d
2.b
3.d
4.c
5.b
6 c
7. a
8.c
9d
10. b
The correct option for the above-given questions are as follows:
1. (c) Condenser lens
[A condenser lens in a microscope helps in focusing light on the specimen. The holder can be adjusted(lowered or raised high)using a specific knob given for adjusting the condenser holder.]
2. (b) 25 cm
[25cm is said to be the least distance of distinct vision for a normal eye. If any object is placed at a distance lesser than this, it can't be seen. This is known as the nearby point for a normal eye.]
3. (d) Wavelength of light used and numerical aperture of the lens system
[Resolving power is a unique feature of the microscope that helps in differentiating between two different points as separate points.]
4. (d) Shortest wavelength of visible light used and an objective with the maximum numerical aperture
[The greatest resolution in light microscopy is obtained with the nearest ultraviolet light which is the shortest wavelength of light.]
5. (a) Exciter filter
[It is a type of optical glass filter used in fluorescence microscopy. It doesn't remove blue light but all other light from the source of the fluorescent specimen from reaching out to the eyes.]
6. (d) Magnifying power of both the objective lens and eyepiece
[Magnifying power is the product of the power of the objective lens and that of the eyepiece. (that is both the powers are multiplied to get the total magnification. ]
7. (c) Heat
[Staining kills germs, so the cells are fixed sometimes. Some commonly used chemical fixations are osmic acid & glutaraldehyde. But in the case of a light microscopy heat is used as a common fixative.]
8. (b) Inversely proportional to their refractive indices
[Phrase contrast microscopy is based on the relation of refractive index and rate of light traveling through the object i.e. inversely proportional.]
9. (c) Diaphragm
[It is the apparatus on the condenser. It helps in allowing the amount of light to enter the viewing area by closing and opening like a shutter.]
10. (c) 1.33
[NA(numerical aperture) is equal to the product of refractive index & sine of the angle of half aperture.]