Frank Cce Everyday Science Solutions for Class 8 Science Chapter 24 Summative Assessment 2 are provided here with simple step-by-step explanations. These solutions for Summative Assessment 2 are extremely popular among Class 8 students for Science Summative Assessment 2 Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the Frank Cce Everyday Science Book of Class 8 Science Chapter 24 are provided here for you for free. You will also love the ad-free experience on Meritnation’s Frank Cce Everyday Science Solutions. All Frank Cce Everyday Science Solutions for class Class 8 Science are prepared by experts and are 100% accurate.

Page No 288:

Question A.1:

Answer:

Adam's apple is the voice box present in our throat. The Adam's apple of a boy is larger than that of a girl. Hence, it is visible only in boys. Adam's apple is responsible for the production of sound.

Page No 288:

Question A.2:

Adam's apple is the voice box present in our throat. The Adam's apple of a boy is larger than that of a girl. Hence, it is visible only in boys. Adam's apple is responsible for the production of sound.

Answer:

Contact force is a force that comes into play only when two objects come in physical contact with each other. Contact force cannot act from a distance. Examples are friction force and muscular force.

Page No 288:

Question A.3:

Contact force is a force that comes into play only when two objects come in physical contact with each other. Contact force cannot act from a distance. Examples are friction force and muscular force.

Answer:

Lubricant is a substance that smoothens the surface of an object and reduces the friction produced by it. Examples are grease and graphite powder.

Page No 288:

Question A.4:

Lubricant is a substance that smoothens the surface of an object and reduces the friction produced by it. Examples are grease and graphite powder.

Answer:

One hertz is defined as one cycle per second of a vibration. It is the SI unit of frequency. Its symbol is Hz.

Page No 288:

Question A.5:

One hertz is defined as one cycle per second of a vibration. It is the SI unit of frequency. Its symbol is Hz.

Answer:

Acidulated water is the water that has some amount of acid in it.

Page No 288:

Question A.6:

Acidulated water is the water that has some amount of acid in it.

Answer:

Tremor is the shaking or vibration of the earth's crust during an earthquake.

Page No 288:

Question A.7:

Tremor is the shaking or vibration of the earth's crust during an earthquake.

Answer:

Lateral inversion can be defined as sideways (or left–right) reversal of the image of an object when viewed in a plain mirror.

Page No 288:

Question A.8:

Lateral inversion can be defined as sideways (or left–right) reversal of the image of an object when viewed in a plain mirror.

Answer:

Light year is a unit of distance. It refers to the distance travelled by light in one year. One light year = 9.4607 × 1012 km.

Page No 288:

Question B.1:

Light year is a unit of distance. It refers to the distance travelled by light in one year. One light year = 9.4607 × 1012 km.

Answer:

Mass Weight
It is an amount or quantity of matter present in a body. It is constant for a given body. It is a measure of gravitational force with which the earth attracts any body towards itself. Weight of a given body is different at different points on the earth.
It is measured in kilograms (kg). It is measured in kilograms-force (kgf) or newton (N).

Page No 288:

Question B.2:

Mass Weight
It is an amount or quantity of matter present in a body. It is constant for a given body. It is a measure of gravitational force with which the earth attracts any body towards itself. Weight of a given body is different at different points on the earth.
It is measured in kilograms (kg). It is measured in kilograms-force (kgf) or newton (N).

Answer:

Worn out tyres create less friction on road due to which they have a very poor grip on roads. This makes such tyres prone to slipping and cause accidents. Therefore, old and worn out tyres are discarded to avoid accidents.

Page No 288:

Question B.3:

Worn out tyres create less friction on road due to which they have a very poor grip on roads. This makes such tyres prone to slipping and cause accidents. Therefore, old and worn out tyres are discarded to avoid accidents.

Answer:

Ultrasonics: These are the sounds with frequencies higher than 20,000 Hz. These sounds are not audible to human beings but are audible to animals like dogs, leopards, monkeys and deer. 

Infrasonics: These are the sounds with frequencies less than 20 Hz. These sounds are also inaudible to human beings.

Page No 288:

Question B.4:

Ultrasonics: These are the sounds with frequencies higher than 20,000 Hz. These sounds are not audible to human beings but are audible to animals like dogs, leopards, monkeys and deer. 

Infrasonics: These are the sounds with frequencies less than 20 Hz. These sounds are also inaudible to human beings.

Answer:

Vitamin A or retinol is essential for maintaining the cells of retina and its pigments, which are responsible for good eyesight. It is a well-know fact that the deficiency of vitamin A causes night blindness. We can therefore say that the vision of human eye depends on nutrition.

Page No 288:

Question B.5:

Vitamin A or retinol is essential for maintaining the cells of retina and its pigments, which are responsible for good eyesight. It is a well-know fact that the deficiency of vitamin A causes night blindness. We can therefore say that the vision of human eye depends on nutrition.

Answer:

Bioconcentration is the aggregation of pesticides in the body of an organism at a particular trophic level in a food chain.
When pesticides are used on crops, a part of these pesticides washes away into the nearby water bodies and gets accumulates in the bodies of fishes. These fishes are then consumed by bigger fishes and birds. Thus, the pesticides keep getting accumulated into the bodies of different organisms present at different trophic levels, through the food chain and the concentration goes on increasing as we move from a lower to higher trophic level. The food chain explained here is just an example and the phenomenon of bioconcentration is operational in all the food chains.

Page No 288:

Question C.1:

Bioconcentration is the aggregation of pesticides in the body of an organism at a particular trophic level in a food chain.
When pesticides are used on crops, a part of these pesticides washes away into the nearby water bodies and gets accumulates in the bodies of fishes. These fishes are then consumed by bigger fishes and birds. Thus, the pesticides keep getting accumulated into the bodies of different organisms present at different trophic levels, through the food chain and the concentration goes on increasing as we move from a lower to higher trophic level. The food chain explained here is just an example and the phenomenon of bioconcentration is operational in all the food chains.

Answer:

Some of the ill effects of noise pollution are as follows:
(i) It may cause loss of hearing, which can also lead to deafness.
(ii) It causes anger and interferes with the sleeping patterns of individuals.
(iii) It causes headache, hypertension and irritability.
(iv) Chronic exposure to loud noise can lead to heart diseases.

Page No 288:

Question C.2:

Some of the ill effects of noise pollution are as follows:
(i) It may cause loss of hearing, which can also lead to deafness.
(ii) It causes anger and interferes with the sleeping patterns of individuals.
(iii) It causes headache, hypertension and irritability.
(iv) Chronic exposure to loud noise can lead to heart diseases.

Answer:

Electroplating is the process of deposition of metal on an electrode. This process can be done through electrolysis. 

Steps involved in the electroplating of an article:

(i) The object or substance that needs to be electroplated is first washed with an alkali solution in order to remove any unwanted particles that may be present over its surface.
(ii) The substance is then washed with dilute acidic solution in order to remove any oxide layer that may have formed on its surface.
(iii) The object is then thoroughly washed with tap water.
(iv) This object acts as the cathode (i.e., the rod that is to be electroplated).
(v) The anode is a thick rod of the substance that is to be deposited.
(vi) Both the rods are dipped in the salt solution of the metal that is to be deposited.
(vii) Both the rods are connected with a battery and the circuit is completed by using a key.
(viii) When current passes through the solution, the cathode gets electroplated.

Page No 288:

Question C.3:

Electroplating is the process of deposition of metal on an electrode. This process can be done through electrolysis. 

Steps involved in the electroplating of an article:

(i) The object or substance that needs to be electroplated is first washed with an alkali solution in order to remove any unwanted particles that may be present over its surface.
(ii) The substance is then washed with dilute acidic solution in order to remove any oxide layer that may have formed on its surface.
(iii) The object is then thoroughly washed with tap water.
(iv) This object acts as the cathode (i.e., the rod that is to be electroplated).
(v) The anode is a thick rod of the substance that is to be deposited.
(vi) Both the rods are dipped in the salt solution of the metal that is to be deposited.
(vii) Both the rods are connected with a battery and the circuit is completed by using a key.
(viii) When current passes through the solution, the cathode gets electroplated.

Answer:

If we are in school and there is an earthquake, then we must take the following protective measures: 
(i) People must take a cover under desks to protect themselves from the debris falling from above.
(ii) Much movement should be avoided.
(iii) A proximity with heavy objects must be avoided.

Page No 288:

Question C.4:

If we are in school and there is an earthquake, then we must take the following protective measures: 
(i) People must take a cover under desks to protect themselves from the debris falling from above.
(ii) Much movement should be avoided.
(iii) A proximity with heavy objects must be avoided.

Answer:

Stars Planets
Stars have their own light. Planets do not have their own light. They reflect the light falling on them from the sun.
Stars twinkle at night. Planets do not twinkle.
Stars are larger in size. Planets are smaller than stars.



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