Compound Microscope

Q. A compound microscope has a magnifying power 30. The focal length of its eye-piece is 5 cm. Assuming the final image to be at the least distance of distinct vision. The magnification produced by the objective will be

1. 5
2. -5
3. 6
4. -6

Q.

When the length of a microscope tube increases, its magnifying power [MNR 1986]

1. Decreases

2. Increases

3. Does not change

4. May decrease or increase

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

1. 1.8 cm

2. 1.5 cm

3. 2.1 cm

4. 2.4 cm

Q.

In a compound microscope, if the objective produces an image $I_o$ and the eye piece produces an image $I_e$, then

1. $I_o$ is virtual but $I_e$ is real

2. $I_o$ is real but $I_e$ is virtual

3. $I_o$ and $I_e$ are both real

4. $I_o$ and $I_e$ are both virtual

Q.

If in compound microscope m₁ and m₂ be the linear magnification of the

objective lens and eye lens respectively, then magnifying power of the

compound microscope will be

[CPMT 1985; KCET 1994]

1. 

2. 

3. 
4. 

Q. If the focal length of the objective lens and the eye lens are 4 mm and 25 mm respectively in a compound microscope. The length of the tube is 16 cm. Find its magnifying power for relaxed eye position

1. 32.75
2. 327.5
3. 0.3275
4. None of the above

Q. The focal lengths of the objective and eye-lens of a microscope are 1 cm and 5 cm respectively. If the magnifying power for the relaxed eye is 45, then the length of the tube is

1. 30 cm
2. 25 cm
3. 15 cm
4. 12 cm
   

Q. In a compound microscope, the focal lengths of two lenses are 1.5 cm and 6.25 cm an object is placed at 2 cm form objective and the final image is formed at 25 cm from eye lens. The distance between the two lenses is

1. 6.00 cm
2. 7.75 cm
3. 9.25 cm
4. 11.00 cm

Q.

The magnifying power of a microscope with an objective of 5 mm focal length is 400. The length of its tube is 20 cm. Then the focal length of the eye-piece is [MP PMT 1991]

1. 200 cm

2. 160 cm

3. 2.5 cm

4. 0.1 cm

Q.

The magnifying power of a microscope with an objective of 5 mm focal length is 400. The length of its tube is 20 cm. Then the focal length of the eye-piece is [MP PMT 1991]

1. 200 cm

2. 160 cm

3. 2.5 cm

4. 0.1 cm

Q. The value of angular magnification if the final image is formed at near point, instead of infinity is .

1. $\frac{L}{f_0}(1+\frac{D}{f_e})$
2. $\frac{LD}{f_e{f}_0}$
3. $\frac{L}{fe}(1+\frac{D}{f_e})$
4. $\frac{L}{f_0}$

Q.

Microscope is an optical instrument which

1. Enlarges the object

2. Increases the visual angle formed by the object at the eye

3. Decreases the visual angle formed by the object at the eye

4. Brings the object nearer

Q. The focal length of objective and eye lens of a microscope are 4 cm and 8 cm respectively. If the least distance of distinct vision is 24 cm and object distance is 4.5 cm from the objective lens, then the magnifying power of the microscope will be

1. 18

2. 32
3. 64
4. 20

Q.

How should people wearing spectacles work with a microscope

1. They cannot use the microscope at all
2. They should keep on wearing their spectacles

3. They should take off spectacles

4. (b) and (c) is both way

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

1. 1.8 cm

2. 1.5 cm

3. 2.1 cm

4. 2.4 cm

Q. In a compound microscope, the focal length of the objective and the eye lens are 2.5 cm and 5 cm respectively. An object is placed at 3.75 cm before the objective and image is formed at the least distance of distinct vision, then the distance between two lenses will be (i.e. length of the microscopic tube)

1. 11.67 cm
2. 12.67 cm
3. 13.00 cm
4. 12.00 cm

Q. A compound microscope is used to enlarge an object kept at a distance 0.03m from it’s objective which consists of several convex lenses in contact and has focal length 0.02m. If a lens of focal length 0.1m is removed from the objective, then by what distance the eye-piece of the microscope must be moved to refocus the image

1. 2.5 cm
2. 6 cm
3. 15 cm
4. 9 cm

Q. If the focal length of the objective lens and the eye lens are 4 mm and 25 mm respectively in a compound microscope. The length of the tube is 16 cm. Find its magnifying power for relaxed eye position

1. 32.75
2. 327.5
3. 0.3275
4. None of the above

Q.

The focal length of the objective lens of a compound microscope is [CPMT 1985; MNR 1986; M

1. Equal to the focal length of its eye piece

2. Less than the focal length of eye piece

3. Greater than the focal length of eye piece

4. Any of the above three