The ratio of resolving powers of an optical microscope for two wavelengths ${\lambda }_1=4000<mspace\; width="1em"></mspace>\stackrel{o}{A<mspace\; width="1em"></mspace>}<mspace\; width="1em"></mspace>and<mspace\; width="1em"></mspace>{\lambda }_2=6000<mspace\; width="1em"></mspace>\stackrel{o}{A}$ is:

1. 8:27

2. 9:4

3. 3:2

4. 16:81

Resolving power of a compound microscope:

1.  Depends on the wavelength of light as \(\propto\) $\lambda$

2.  Depends on the wavelength of light as \(\propto\) $\lambda$²

3.  Depends on the wavelength of light as \(\propto\) $\frac{1}{\lambda }$

4.  Depends on the wavelength of light as \(\propto\) $\frac{1}{{\lambda }^2}$

The angular resolution of a 10 cm diameter telescope for a wavelength of 5000 Å is of the order of:

1. 10^–4 rad

2. 10^–6 rad

3. 10⁶ rad

4. 10^–2 rad

A telescope has an objective lens of 10 cm diameter and is situated at a distance of one kilometre from two objects. The minimum distance between these two objects, which can be resolved by the telescope, when the mean wavelength of light is 5000 Å, is of the order of:

1. 5 m

2. 5 mm

3. 5 cm

4. 0.5 m

The resolving power of a compound microscope will be maximum when:

Assume that light of wavelength 600 nm is coming from a star. The limit of resolution of telescope whose objective has a diameter of 2 m is:

1. $1.83\times {10}^{-7}$ $rad$

2. $7.32\times {10}^{-7}$ $rad$

3. $6.00\times {10}^{-7}$ $rad$

4. $3.66\times {10}^{-7}$ $rad$

The resolving power of a microscope can be increased by using:

1.  red light.
2.  blue light.
3.  oil between objective lens and object.
4.  both (2) and (3).

The distance of the moon from the earth is $3.8\times {10}^5<mspace\; width="1em"></mspace>km$. The eye is most sensitive to light of wavelength 5500 Å. The minimum separation between two points on the moon that can be resolved by a 500 cm telescope will be:

1. 51 m                         

2. 60 m

3. 70 m                         

4. All the above

The diameter of the human eye lens is 2 mm. What will be the minimum distance between two points to resolve them, which are situated at a distance of 50 meters from the eye? The wavelength of light is 5000 Å:

1. 2.32 m

2. 4.28 mm

3. 1.52 cm

4. 12.48 cm

The graph between resolving power and accelerating potential V for an electron microscope is (P is resolving power):

1.		2.
3.		4.