Advertisements
Advertisements
Question
i. Which type of microscope has the arrangement of lenses shown in the adjoining figure?
ii. Label the figure correctly.
iii. Write the working of this microscope.
iv. Where does this microscope used?
v. Suggest a way to increase the efficiency of this microscope.
Advertisements
Solution
i. Compound microscope
ii. Scientifically and technically correct figure.
(Object, Objective lens, Eye piece, Image)
iii. Magnification is obtained by the combined effect of two
lenses. The magnification occurs in two stages. The image formed by the first lens acts as the object for the second lens. Clear image can be obtained by adjusting the distance between two lenses.
iv. To study small sized objects like blood cells, animal and plant
cells, bacteria.
v. Any relevant remedy (For example, Selection of lens with
appropriate focal length)
APPEARS IN
RELATED QUESTIONS
One-half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object? Verify your answer experimentally. Explain your observations.
Parallel rays of light are refracted by a convex lens to a point called the ______.
State whether the convex lens has a real focus or a virtual focus.
A convex lens of focal length 8 cm forms a real image of the same size as the object. The distance between object and its image will be:
A burning candle whose flame is 1.5 cm tall is placed at a certain distance in front of a convex lens. An image of candle flame is received on a white screen kept behind the lens. The image of flame also measures 1.5 cm. If f is the focal length of convex lens, the candle is placed:
(a) at f
(b) between f and 2f
(c) at 2f
(d) beyond 2f
Describe the nature of image formed when an object is placed at a distance of 30 cm from a convex lens of focal length 15 cm.
A convex lens produces an inverted image magnified three times of an object placed at a distance of 15 cm from it. Calculate the focal length of the lens.
A convex lens of focal length 15 cm produces a magnification of +4. The object is placed:
(a) at a distance of 15 cm
(b) between 15 cm and 30 cm
(c) at less than 15 cm
(d) beyond 30 cm
A student did an experiment with a convex lens. He put an object at different distances 25 cm, 30 cm, 40 cm, 60 cm and 120 cm from the lens. In each case he measured the distance of the image from the lens. His results were 100 cm, 24 cm, 60 cm, 30 cm and 40 cm, respectively. Unfortunately his results are written in wrong order.
- Rewrite the image distances in the correct order.
- What would be the image distance if the object distance was 90 cm?
- Which of the object distances gives the biggest image?
- What is the focal length of this lens?
Which type of lenses are:
thicker in the middle than at the edges?
What kind of lens can form:
am erect diminished image?
A lens forms an inverted image of an object. Name the kind of lens.
A lens forms an upright and magnified image of an object State whether the image is real or virtual
In the following cases, where must an object be placed in front of a convex lens so that the image formed is of the same size as the object?
Complete the following table:
| Type of lens | Position of object | Nature of image | Size of image |
| Convex | Between optical centre and focus | ||
| Convex | At focus | ||
| Concave | At infinity | ||
| Concave | At any distance |
State the position of object, position of image, nature of image when: Convex lens is used as objective lens of astronomical telescope.
Distinguish between:
Concave lens and Convex lens
