A microscope is focused on a mark on a piece of paper and then a slab of glass of thickness 3 cm and a refractive index 1.5 is placed over the mark. How should the microscope be moved to get the mark in focus again?

1. 1 cm upward

2. 4.5 cm downward

3. 1 cm downward

4. 2 cm upward

The magnification of a compound microscope for the final image at least distance of distinct vision is 90. The magnification of the objective lens is 15. The value of the focal length of the eyepiece will be

(1) 5 cm

(2) 6 cm

(3) $\frac{1}{6}$ cm

(4) 12 cm

If four convex lenses, given to you have focal lengths $f_1<f_2<f_3<f_4$, then which of the following combination will you prefer to form a compound microscope?

(1) $f_1$ as objective and $f_4$ as eye-lens

(2) $f_1$ as objective and $f_2$ as eye-lens

(3) $f_4$ as objective and $f_1$ as eye-lens

(4) $f_2$ as objective and $f_3$ as eye-lens

In case of a compound microscope, the image formed by the objective lens is

(1) Virtual, erect and diminished

(2) Real, erect and magnified

(3) Virtual, inverted and enlarged

(4) Real, inverted and enlarged

The maximum magnification which can be obtained with the help of a simple microscope is 6. If a point object is placed at distance 3 cm from the microscope, then what was be the position of the image?

(1) -7.5 cm

(2) -6.4 cm

(3) 8.2 cm

(4) 5.45 cm

Focal lengths of objective and eyepiece of a compound microscope are 2 cm and 6.25 cm respectively. An object AB is placed at a distance of 2.5 cm from the objective which forms the image A'B' as shown in the figure. Maximum magnifying power in this case is

1.  10

2.  20

3.  5

4.  25

The correct statement is:

A compound microscope has two convex has a system with focal lengths 2 cm and 5 cm. An object is 2.5 cm away from the objective lens. The tube length of the microscope when magnification is maximum is equal to

1. 18.2cm

2. 14.2 cm

3. 8.2 cm

4. 4.2 cm

The length of a compound microscope is 14 cm. The magnifying power for a relaxed eye is 25. If the focal length of the eye lens is 5 cm, then the object distance for the objective lens will be

1.  1.8 cm

2.  1.5 cm

3.  2.1 cm

4.  2.4 cm

A compound microscope has an objective lens with a focal length of \(1.5~\text{cm}\) and an eyepiece of focal length \(5~\text{cm}\). It is focussed on an object which is at a distance of \(1.8~\text{cm}\). The length of the microscope for normal adjustment is: 
1. \(14~\text{cm}\)
2. \(2~\text{cm}\)
3. \(19~\text{cm}\)
4. \(9.5~\text{cm}\)