Question

. A compound microscope uses light to transmit an image to our eye. Compound microscope has a combination of two lenses to magnify the image of a specimen (object). Light from a source strikes the mirror, fitted in lower part of microscope, which reflects the light towards condenser lens. Condenser lens converges the light radiations onto the specimen. Light passes through the specimen and into the objective lens. Objective lens projects a real, inverted and magnified image of specimen on an intermediate image plane inside the microscope. Eyepiece, another lens, further magnifies the real image projected by objective lens. Eyepiece fits into the upper part of microscope through which observer observes the specimen. It produces an enlarged, virtual and erect image of the real image projected by objective lens. It's working can be understood with the help of following schematic diagram:-

i) A microscope is called compound microscope when it uses

One magnifying lens and one mirror
Two magnifying lenses
One magnifying lens and one condenser lens
Three magnifying lenses

ii) Objective lens and eyepiece are *

Convex and concave lenses respectively
Concave and convex lenses respectively
Both convex lenses
Both concave lenses

iii) Following light related phenomenon/phenomena is/are used in the working of compound microscope *

Reflection and refraction
Reflection, refraction and scattering
Reflection
Refraction

iv) Focal length of a convex lens *

Is always positive
Is always negative
Can be positive or negative depending upon the distance of object
Can be positive or negative depending upon the thickness of lens
v) The intermediate image is formed at such a distance that it lies on principal axis of eyepiece *

At principal focus
Between centre of curvature and principal focus
Between principal focus and optical centre
At centre of curvature

7. A food chain is a linear sequence of organisms through which nutrients and energy pass as one organism eats another. In food chain organisms occupy a different tropic level. Food chains give us a clear-cut picture of who eats whom. But in an ecosystem an organism can sometimes eat more than one type of prey or can be eaten by more than one type of Predator. Such organisms become part of different food chains acquiring different tropic levels at the same time. Geographical representation of this natural interconnection of food chains is called food web. Two different examples of food webs are represented below:-

i) In food web A, which of the following organisms occupy both 4th and 5th trophic levels in different food chains? *

Butcher bird and native cat
Robin and and parasitic wasp
Lizard and butcher Bird
Parasitic wasp and native cat

ii) Food web which represents more stable ecosystem is *

Food web A
Food web B
Equally stable in both food web A and food Web B
Cannot be concluded from the given data

iii) Which of the following statement is incorrect about food chain in an ecosystem? *

Only 10% of energy is transferred from one trophic level to next
Higher the trophic level greater will be the number of individuals
Most of the food chains consist of 4 to 5 trophic levels
Flow of energy is unidirectional in a food chain

iv) Which of the following decreases the stability of ecosystem due to the loss of biodiversity? *

Prey Predator interaction
Biomagnification
Both a and b
None of these

v) Food webs A and B are in different locations. If leafhopper died out in both locations which one of these is best prediction and explanation for the effect this would have on the food webs? *

The effect would be greater in food web A because parasitic wasp has only one food source in food web A

The effect would be greater in in food web a because parasitic wasp has several food sources in food web A

The effect would be greater in food web B because parasitic wasp has only one food source in food web B

The effect would be greater in food web B because parasitic wasp has several food sources in food web B
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Answer 1

Answer:

Explanation:

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Answer 2

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