Q1.While passing nearby a pond, some students saw a drowning man screaming forhelp. They alerted another passerby, who immediately threw an inflated rubber tube in the pond. The man was saved.· Why the passerby did use inflated rubber tube to save the drowning man? ·Write the principle involved here.· Which qualities shown by the students and the passerby do you identify that helped in saving the drowning man?
Q2.You received an e-mail from a friend living in a coastal town. He shared an experience with you that recently, while swimming on the coastline of the sea in common swimming attire, he thought of going deeper inside the sea. He was asked to abstain from delving deeper into the sea by the rescue personnel. Respond to the following questions using the information provided above.Why the rescue personnel asked your friend not to swim deeper inside the sea? · What values were exhibited by the rescue personnel?
Q3.Nitya is visiting her relativesin Bhopal. One day her aunt expressed unhappiness with the milk supplied by the milkman. She complained of adulterated milk. Nitya asked her to buy an instrument to check the purity of milk. Next day, the supplied milk was tested and found water being mixed in the milk. Nitya's aunt informed all her neighbors about the instrument.· What values are shown by Nitya, her aunt and the milkman respectively? · Identify the instrument and the principle on which it is based?
Q4.During the summer vacations, Gaurav visited his native village. He observed that for washing clothes, villagers used the water from the well. Out of curiosity he drew water from the well and observed that the bucket of water appeared to be heavier asit came out of the water.· Name the principle used in the above passage.· Why bucket appears to be heavier in air? · Which values are reflected in Gaurav's behavior.
Chapter WORK AND ENERGY
Q.1An educational tour to Mumbai was organized. While visiting the seashore,Vyom,one of the students observed that direction of wind changed during the day time and night. He asked his science teacher who accompanied them, the possible reasons for his observations.· What possible reasons, teacher gave to the student.· Name two other factors which influence winds.· Comment on the values shown by the student.
Q2.Due to heavy rains and speedy winds a tree broke and fell on the road. Two persons from local shops came and begin to remove that broken part of the tree,but in vain as the log was too heavy. A passerby came to their help with a few solid heavy sticks. Consequently, the heavy log was put aside and the commutationon the road began as usual.· Comment upon the value(s) displayed by the passerby?· Name the energy stored when the heavy log of the tree waslifted to some height?
Q3.Mr. Shah's family was worried about heavy electricity bills to be paid. Their neighbour Mr. Sen suggested some easy and effective steps to reduce the same. Next month's bill came as a relief to Mr. Shah, as the consumption of electricity had reduced by 50 units and so had the bill.· What is the unit of ``Power''.· What is it a measure of energy or power? · Write any three steps that you think Mr. Sen might have suggested to Mr. Shah.
Q4.Amit and Nitin were observing a building having two different staircase. One slanting and other vertically spiral. Amit was of the opinion that a person using slanting staircase will be doing more work against gravity but Nitin thought otherwise. They started quarrelling. Asif, their friend, explained and gave entirely different view and pacified them.· What according to you was the explanation given by Asif? · What appreciable values do you see in the Asif?
Q5.Four tubelights of 60 watt each, three fans of 60 watt each and a geyser of 500 watt operates for eight hours everyday in a household. The electricity bill made Mr. Abhinav worried. He discovered the usage of geyser, unnecessary longer. He conveyed to the family membersthat energy guzzling appliances and gadgets ought to be wisely used according to the need.(hint:- 1watt = 0.001 kilowatt = 1 unit)· Calculate the total electrical units of energy consumed if the month is September.· Comment upon the values demonstrated by Mr. Abhinav.· Convert 1 kilowatt hour into joules.
Q6.Aditya and his friends were playing with a catapult (gulel) in his garden. Several mangoes were dislodged and fell with the help of catapult. One of his friend was aiming the catapult on a bird. Aditya prevented him from doing so.· Name the energy possessed by the stretched string of the catapult· What will happen if the stone isthrown without stretching the string of a catapult? ·Why Aditya did prevent his friend from aiming at the bird?Which quality is highlighted inAditya's behavior?
Q7.Raghu lives in a village and his school is 8 km away from his home. His father suggests buying a motor cycle to go to school. Raghu opposesthe idea and opt fora bicycle instead.. Write the energy transformation taking place while Raghu rides his bicycle.· If Raghu paddles the bicycle with a speed of 8 Km/hr and he wantsto Reach
10 minutes before the school commences. Whatshould be the duration before which he must leave his house?· Justify the stand taken by Raghu in your own words.
Chapter SOUND
Q1.In a hot summer afternoon a man was shouting through a megaphone. He was'zip-repairer'. As Arshi was preparing for her examination, she got disturbed. She inquired her father about the instrument being used by the 'zip-repairer'. The fathertold her that it was a megaphone also known as 'loud hailer'.· State the principle on which the megaphone works.· Why did Arshi get disturbed?· Why megaphones should not be used in residential area?
Q2.Kunal andAbhimanyu were waiting to go across a railway crossing. Kunal jumped over the barrier and curiously put his ear on the railway track.Abhimanyu opposed Kunal and pulled him away from the railway track.· Why did Kunal put his ear on the railway track? · Can sound travel faster through, (i). Copper (ii). Water. Why did Abhimanyu pulled Kunal away from the railway track?
Q3.Ashish had a pain in his ear as he pricked it with a pin. The doctor advised we should take proper care of our ears and protect them from damage.· Why we must not prick with hard and pointed things inside our ears? · What is the function of ear?
Q4.Reena's grandmother took her mother to a doctor ass he was four months pregnant for ultra-sonography. But she showed her interest in determining whether the child is a boy or a girl. The doctor was annoyed and refused to disclose the gender ofthe child.· What is ultra-sonography?· On what principle does it work?· Why do you think the doctor refused to determine the gender of the child? · Why is ultrasonography important?
Q.5Harsha was watching a program based on ships on television. She saw a device attached to a ship through which the men on the ship located the enemy submarines and sent the message to the headquarters.· Name the device fitted in the ship.· Write the full form of the device.· On which principle does the device work? · Write other uses of the device.