Explore topic-wise InterviewSolutions in Current Affairs.

Stomata are the small openings present on the lower surface of the leaf through which gaseous exchange takes place.

The correct answer is A) Autotrophic.

The green parts of plant contain a colouring pigment called chlorophyll.

The correct answer is B) Photosynthesis.

No, there are some heterotrophic plants like cuscuta.

Chlorophyll captures the energy of the sunlight. This energy is used to synthesise  food from carbon dioxide and water dhfihg photosynthesis.

Yes. It is very important. If we do not clean odr teeth properly after food, some food material will stuck in between teeth and causes tooth decay.

I have collected the following plants and classified them in to following categories. 

Autotrophs: 

Neem, mango, hibiscus, Paddy 

Parasites: 

Cuscuta, loranthus. 

Saprophytes: 

Mush rooms, Moulds 

Symbionts: 

Red gram, beans, I preserved these specimens in the biology laboratory of our school.

1. Saprophytes grow on dead and decaying matter. 

2. They secrete digestive juices on it, convert it into a solution and then absorb the nutrients from it.

3. During this process they decompose them and mix them with the soil. 

4. In this Way they help in cleaning the earth surface by removing the dead and decaying matter. 

5. This process help in recycling the nutrients too.

6. Thus they are doing a great service to the entire living world.

Certain microorganisms such as bacteria and fungi like mushrooms, bread mould are ‘ the examples for saprophytes.

1. Type of association between two organisms for food in which one organism get benefited and other is vitiated is called parasitism (Parasitic nutrition). 

2. The organism which is getting benefit is called parasite. 

3. Example for parasitic plant is Cuscuta. 

4. Example for parasitic animal is intestinal worm.

1. Plants like Cuscuta/ Dodder plant (Bangaru teega) take readymade food from the plant on which it is climbing. , 

2. They develop special roots called haustoria, which penetrate into the tissues of the host plant and absorb food materials from them. 

3. This causes harm to the host plant gradually.

4. This kind of nutrition is called parasitism.

Plants take carbon dioxide from air, water from soil, light energy from sun light and prepare their own food by using chlorophyll present in its green parts.

Animals get their food from plants and animals.

1. Animals cannot make food. 

2. They depend on other plants and animals for food.

1. Grass eating animals have four chambers in stomach. 

2. They are rumen, reticulum, omasum and abomasum.

3. They quickly swallow the grass and store it in a part of the stomach called rumen. 

4. In rumen, food gets partially digested and is called cud. 

5. But later the cud returns to the mouth in small lumps and animal chews it again. 

6. This process is called rumination and these animals are called ruminants. 

7. The grass is rich in cellulose, a type of carbohydrate. 

8. In ruminants, the cellulose of the food is digested by the action of certain bacteria present in the rumen of grass eating animals.

Heterotrophic nutrition is seen in animals.

1. Cuscuta take readymade food from the plant on which it is climbing. 

2. It develops special roots called haustoria, which penetrate into the tissues of the host plant and absorb food materials from them.

1. Animals obtain their food from other organisms. 

Ex : 

Cow eats grass, cat drinks milk, dog eats meat. 

2. They take the food in the form of solid or liquid.

1. Animals take food into the body for digestion. 

2. Digestion occurs inside the body.

Incident ray – light which falls on the mirror/ polished surface is called incident ray. 

Reflected ray – ray of light which goes back in the same medium after striking the surface is called reflected ray. 

Normal – the perpendicular drawn to the reflecting surface is called normal at that point. 

Angle of incidence – the angle between the incident ray and the normal is known angle of incidence. 

Angle of reflection – the angle between reflected ray and the normal is known angle of reflection.

(i) Scattering of light - Phenomenon of spreading of light (diffused, reflection) by minute particles in a medium.

(ii) The sky appears blue because of the blue color of sunlight scatter much more strongly than the red colour by particles in atmosphere/ air due to its shorter wavelength.

(iii) At sun-rise and sun-set most of the blue light and shorter wavelengths are scattered away by the particles in the atmosphere as the light from the sun near the horizon passes through thick layers of air and larger distance. The light that reaches us is of a longer wavelength (red colour) giving a reddish appearance.

The smoke and ash raise up, mixes with gases in the atmosphere which leads to pollution.

The answer is (b) outer surface of the cornea

• Cornea is a thin membrane through which light is entered. 
• The incident light rays are bent due to cornea and are converged which results in image formation at retina. 
• So, most of the refraction occurs at the iris of the eye.

At the Principal focus.

The sun is visible to us about 2 minutes before the actual sunrise, and about 2 minutes after the actual sunset because of atmospheric refraction.

The answer is (b) Scattering of light

• Because red color scatters the least it travels long distance. 
• During sunset or sunrise light has to travel long distance to reach the earth.
• Hence light will be red when it reaches us.

Isaac Newton.

This causes due to the gradual weakening of the ciliary muscles and diminishing flexibility of the eye lens.

A common type of bi-focal lense is necessary to correct this defect.

Correct option is  C) bifocal

A ray of light passing through the centre of curvature of a concave mirror is reflected back along the same path because it strikes the concave mirror at right angles to its surface due to which the angle of incidence and angle of reflection both are o° .

(i) Myopia is corrected using spectacles containing concave lenses. The whole purpose of using concave lenses is to reduce the converging power of the eye lens and hence helping in forming the image of the distant object on the retina of the myopic eye.

(ii) Presbyopia defect is corrected using the spectacles containing convex lenses. The whole purpose of using concave lenses is to increase the converging power of the eye lens and hence helping in forming the image of the nearby object on the retina of the myopic eye.

Student is suffering from myopia. It can be corrected by using concave lens of appropriate focal length and power. The light rays meet before retina and hence concave lens will help the rays to diverge further and help them in meeting on retina.

C) the least distance of distinct vision

 (a) Alternating current. (b) Direct current.

(i) It depends on the size of the particles.

(ii) (a) Large-sized particles scatter light of longer wavelengths.

(b) The amount of scattering is inversely proportional to the fourth power of wavelength.

Shaving mirror – concave mirror.

Car headlight mirror – concave mirror.

Searchlight mirror – concave mirror.

Driving mirror – convex mirror.

Dentist’s inspection mirror – concave mirror.

Torch mirror – concave mirror.

Staircase mirror in a double-decker bus – convex mirror.

Make-up mirror – concave mirror.

Solar furnace mirror – concave mirror.

Satellite TV dish – concave mirror.

Shop security mirror – convex mirror.

Presbyopia: This defect is caused due to ageing. The person suffering from this disease cannot see nearby as well as far off objects. It is caused due to weakening of ciliary muscles. The lens is not able to change the focal length. It can be corrected by using bi-focal lens.

1. (ii) Least scattered by smoke or fog

2. (i) TRUE

3. (i) YES

4. (i) TRUE

5. (i) Violet

A normal human eye has a near point of 25 cm, anything closer to it is not seen clearly.

The seven colours of the spectrum of white light are denited by the word VIBGYOR where V stands for Violet, I for Indigo, B for Blue, G for Green, Y for Yellow, O for Orange and R for Red. It is connected with the phenomenon of dispersion of light. 

When we are underwater, incoming light rays are hardly bent, or focused, at all. Our eye lens is designed to see in air. The eye lens bends the rays a little, but due to the lost corneal refraction, the light that reaches the retina isn't focused and thus cannot see very clearly underwater even if the water is absolutely clear. Hence diver observes a blurred vision.

Infrared radiation has the maximum wavelength and minimum frequency. 

Energy is directly proportional to frequency; hence energy associated with them is also low. 

Thus the infrared radiation gets least scattered by the tiny particles in the fog. 

That is why infrared wave is preferred over all others which have a higher frequency and gets scattered hence can’t be focused.

Due to refraction of light an object placed in a denser medium, when viewed from rarer medium appears to be at a lesser depth than its real depth. 

This depth is called the apparent depth. 

Apparent depth = real depth/ n 

Where, 

n = refractive index of the denser medium with respect to the rarer medium 

Violet light slows down more than red light, so it is refracted at a slightly greater angle, so refractive index (n) is maximum for the violet colour. Hence its apparent depth would be the least, the violet coloured letter V would be raised to the maximum.

The image of all the letters of the word VIBGYOR in their corresponding colours will not be at the same place. In glass, red colour has the higher speed than violet colour, so red will be raised to the maximum while violet will be at the bottom and the other colours will be raised in the order I-B-G-Y and orange. 

1. (i) Myopia

2. (ii) Concave lens

3. (i) -1.667 D

4. (ii) -0.60 m

5. (i) Concave lens

1. (i) Myopia

2. (ii) Concave Lens

3. (ii) Short sightedness

1. (i) Myopia

2. (i) Infinity

3. (i) Reciprocal of its focal length

4. (ii) \(\frac1{Power}\)

5. (i) Dioptre

1. (i) Myopia

2. (ii) By using concave lens of suitable focal length

3. (ii) NO

4. (ii) Power of accommodation

5. (ii) In front of the retina