NCERT -Solution – Class 7th – Chapter 5 -Transfer in Heat
In this post we will see class 7th Science Chapter Transfer in Heat – based on NCERT. It can be used for all the students studying in CBSE boards or any board which are using the NCERT books for their syllabus. All the answers are prepared by Expert teachers and are very useful for all the board using NCERT like CBSE, State boards
EXERCISE – 1-Answer in Brief
Question -1 Write the three types of transferring heat?
Solution – Heat can be transferred in three different ways – Conduction , convection and radiation
Question – 2 Define conduction?
Solution – The transfer of heat from a hot object to a less hot object when they are in contanct is called of conduction of heat
Question – 3 List the condition needed to transfer of heat by conduction?
Solution – For heat to be transferred from one body to another by conduction two condition have to satisfed ;-
[1] The two body should be in contanct
[2] The two bodies should be at different temperature
Question – 4 what are good conductior of heat ? Give two example
Solution – Material that conduct heat readily are called good conductor EG – Iron and copper
Question – 5 What do you mean by convection of heat ?
Solution – The process by which heat is transferred in liquid and gases by actual movement of molecules is called convection
Question – 6 What are convection current ?
Solution – The contionus movement that is seen When a warmj substance rises and cold substance settle down in its place is called convenction current
Question – 7 On what factor does the heat rediate by a shot body depent ?
Solution – Heat radiated by a body depend on its temperature its colour and the nature if its surface
Question – 8 What is the function of reflection provided in an electric room heater ?
solution – In an electric room heater a polished reflector is provided behind the heating element to reflect radiant heat twowards the front
Question – 9 Why is it advisible to wear white or light coloured clothes on a hot day ?
Solution – White and light coloured clothes are worn in hot days because they do not absorb heat and hence keep us warm
Exercise – 2nd Answer in Long
Question -1 Explain how conduction of heat occures in a solid metal rod ?
Solution – When a solid metal rod its molecule recive this heat energy and start vibrating faster this vibration include the neighbouring molecule to vibrate faster too thus heat is transferred from one end of a metal rod to another
Question -2 Why are liquid and gases occures in a conductor of heat ?
Solution – Liquid and gases such poor conductor of heat because their particles not close together as in a solid
Question – 3 What is the adavantage of using a copper in vessels ? Why are their handles made of wood
Solution – Copper is a better conductor of heat then most metals the bottom of cooking vessels are often made of copper The handles are made of wood because metal attractes heat fasility the heat occured in a metal rod could burn hand
Question – 4 Explain how convenction occures ?
Solution – When liquid and gases are heated they expand and rise the coller liquid or gas moves down to take the place that occupied by the warm liquid or gas the coller substance similary gets heated up and rises the process continue tilol entire substance is heated
Question – 5 Why is it good to have ventilaters at the top of the wall ?
Solution – Houses and theraters have tall windows or opening called ventilitars near their selling hot air rises and escapes through the ventilitars near the roof it is replaced by the cool air that comes through doors and window
Question – 6 Explain about the thermos flask ?
Solution – The contant of the flask loose minimal vacum are poor conductor of heat the space between the double wall to is vacumm and does not have any liquid or gas thererfore there is little less of heat due to convenction as the inner wall of the glass bottle are silvered any heat that may be radiated is reflected back in the flask
Exercise – 3rd – Multiple choice question
[1] The transfer of heat from a hot object to a less hot object when they are in contant is called
[1] Conduction [2] Convection [3] Radiation [4] Expation
Answer – Conduction
[2] Heat is transferred from one body to another by conduction ,if
[1] The two bodies are in contanct
[2] They are at different temperature
[3] they are good insulators of heat
[4] They have the same temperature
Answer – The two bodies are in contant and they are at different temperature
[3] Which of these is an application of a conductor ?
[1] Steel vessels are used for cooking
[2] ice blocks are wrapped in sawdust and cloth
[3] We wear woolen clothes in winter
[4] The handles of cooking vessels are made of wood
Answer – Steel vessels are used for cooking
[4] Land and sea breeze occur due to
[1] Conduction [2] Rdation [3] convenction [4] condition
Answer – Convection
[5] Which of these does not require a medium
[1] conduction [2] convection [3] radiation [4] condition
Answer – Radiation
[6] . Heat is transferred through vacuum b y ____________ .
[1] convection [2] conduction [3] condition [4] radiation
Answer – Radiation
Exercise – 4th Fill i n the blanks
[1] When an object is heated its ___________ start vibrating faster Answer – [Molecule]
[2] Conduction is very fast in _______________ Answer – [Solid ]
[3] __________ of heat requires the objects to be in contact Answer -[conduction]
[4] __________ is an example of a liquid which is a good conductor Answer -[mercury]
[5] Ventilators use ___________ to cool a room Answer – [Expart]
[6] Objects that are _______ in colour absorb more heat than objects that are __________ in colour Answer –
[dark and light ]
[7] in a thermos flask the silvewring of the walls prevents loss of heat by___________ Answer – [ Convection]
Exercise – 5th True or False
[1] Conduction of heat is more efffective when molecules are packed closer together? [True]
[2] Liquid and gases are good conductors of heat ? [ False]
[3] Heat is transferred from one end of a solid to another by conduction [ True]
[4] The only kind of heat transfer that involves movement of moelcule is convection [ True]
[5] Sea breeze are caused by radiation [ False]
[6] If a medium is present between two bodies Radiation cannot be occured [False]
[7] Light -coloured objects absorb more heat than darker clothes [False]
[8] A thermos flask can keep hot liquid hot but cannot keep cold liquid cold [False]
Tags:-class 7th science solution ,transfer of heat 7th science solution,ncert solution class 7th science ,ncert solution chapter wise class 7th science ,ncert solution 7th class, ncert solution class 7th ,science book solution ncert 7th
