NCERT Solutions Class 8 Science Chapter 15 Some Natural Phenomena
NCERT Solutions Class 8 Science Chapter 15 Some Natural Phenomena: National Council of Educational Research and Training Class 8 Science Chapter 15 Solutions – Some Natural Phenomena. NCERT Solutions Class 8 Science Chapter 15 PDF Download.
NCERT Solutions Class 8 Science Chapter 15: Overview
|Some Natural Phenomena|
NCERT Solutions Class 8 Science Chapter 15 – Some Natural Phenomena
CHAPTER: – 15 (SOME NATURAL PHENOMENA)
1) Which of the following cannot be charged easily by friction?
(a) A plastic scale
(b) A copper rods
(c) An inflated balloon
(d) A woollen cloth.
Ans: – Option(b).
Explanations – (As the surface of copper rods is rough as compared to the other)
2)When a glass rod is rubbed with a piece of silk cloth the rod
(a) and the cloth both acquire positive charge.
(b) becomes positively charged while the cloth has a negative charge.
(c) and the cloth both acquire negative charge.
(d) becomes negatively charged while the cloth has a positive charge.
Ans: – Option(d).
Explanations – (This silk which is rounded the rod produces the electricity)
3) Write T against true and F against false in the following statements.
(a) Like charges attract each other (T/F)
Ans: – False.
Explanations – (The positive and negative charges attract each other)
(b) A charged glass rod attracts a charged plastic straw (T/F)
Ans: – True.
Explanations – (As both are in opposite charges)
(c) Lightning conductor cannot protect a building from lightning (T/F)
Ans: – False.
Explanations – (As in lightening there are huge amount of electricity present)
(d) Earthquakes can be predicted in advance (T/F)
Ans: – False.
Explanations – (After it happening Richter scale predict it)
4) Sometimes, a crackling sound is heard while taking off a sweater during winters. Explain.
Ans: – As we all know the sweater of us is made up with the cotton wool which rubbed the whole body so, when we take off then it produces some electric charges. And because of the effect of some electric charges, we heard a crackling sound.
5)Explain why a charged body loses its charge if we touch it with our hand.
Ans: – Our body works as a medium of electricity transfer to the earth. So, when we touch the charged body then this charge passes throughout the body and go into the earth. As a result, we feel shock whenever we touch an electric wire.
6)Name the scale on which the destructive energy of an earthquake is measured. An earthquake measures 3 on this scale. Would it be recorded by a seismograph? Is it likely to cause much damage?
- The earthquake is measured by the Richter scales.
- The value of 3 in the earthquake scale would be measured by the Richter scales.
- As this value is light as compared to the destruction happen because of the high value like above 6. So, this will not affect.
7)Suggest three measures to protect ourselves from lightning.
Ans: – The measure for protection of lighting is
- Go into a concrete shaded region at that time.
- Avoid wide field.
- Don’t go in the Shadow of high trees.
8)Explain why a charged balloon is repelled by another charged balloon whereas an uncharged balloon is attracted by another charged balloon?
Ans: – The charged particles always repeal each other and the uncharged particles attract by the charged particles. So, as this balloon have same charges this will repeal by each other but the uncharged attracted by the charges one.
9)Describe with the help of a diagram an instrument which can be used to detect a charged body.
10)List three states in India where earthquakes are more likely to strike.
Ans: – Mostly the northeast state of India and the northern state is earthquake happen. This are Assam, Uttrakhand, Jammu and Kashmir etc.
11)Suppose you are outside your home and an earthquake strikes. What precaution would you take to protect yourself?
Ans: – If the earthquake strike’s when I am present in outside of the room the first thing which I should do is took out the whole person of the home outside and then also helps other to coming out from old houses most as this are more vulnerable places.
12)The weather department has predicted that a thunderstorm is likely to occur on a certain day. Suppose you have to go out on that day. Would you carry an umbrella? Explain.
Ans: – As the weather department already predicted that there is a chance of thunderstorms in an area so, I must carry an umbrella as there is possibility of rainy season. The raincoat also be very helpful in that situation which should be carryout if possible.