Free Heat 01 Practice Test - 7th grade
Question 1
Which of these is true about the direction of heat flow?
SOLUTION
Solution : A
Heat flows from a hot body to a cold body. When two bodies, one hot and another cold, come in contact with each other, the fast moving molecules of the hot body collide with the slow moving molecules of the cold body and the molecules of cold body becomes faster. As a result, the molecules of hot body become slower and the body becomes cooler, whereas the cold body becomes warmer. This continues till both the bodies reach a common temperature, i.e thermal equilibruim is attained.
Question 2
____ is the device used to measure temperature.
SOLUTION
Solution : B
A thermometer is an instrument used for measuring temperature. Some of the common thermometers used are clinical, lab and digital thermometer.
A manometer is an instrument used to measure pressure differences.
An ammeter is used to measure current.
A stethoscope is an acoustic medical device used for listening to the internal sounds of an animal or human body.
Question 3
Which of the following is used to measure body temperature?
SOLUTION
Solution : A
A clinical thermometer is used to measure body temperature. It indicates temperatures from a minimum of 35∘C or 95∘F to a maximum of 42∘C or 108∘F.
Question 4
Which thermometer is used to measure the extreme temperatures of the day, as reported in a newspaper?
SOLUTION
Solution : C
A Max-Min or Six's thermometer is used to measure the maximum and minimum temperatures of the day.
The Six's thermometer is a registering thermometer which can record the maximum and minimum temperatures reached over a period of time, for example, 24 hours. It is used to record the extremes of temperature at a location.
Question 5
A material which allows heat to easily pass through it is known as
conductor
insulator
radiator
resistor
SOLUTION
Solution : A
A conductor allows heat to pass through it whereas an insulator obstructs the passage of heat. A radiator is a substance which emits heat or light.
Question 6
The mode of heat transfer between the sun and earth is ____.
conduction
absorption
radiation
convection
SOLUTION
Solution : C
Radiation is the mode of heat transfer between the earth and the sun. Radiation is a method of heat transfer that does not rely upon any contact between the source and the object. The transfer of heat by radiation does not require any medium. It can take place whether a medium is present or not.
Question 7
Which of the following cools down faster?
Land
Water
Both cool down at the same rate
Sometimes land and sometimes water
SOLUTION
Solution : A
Land cools down faster than water. As a result during night, the air above land becomes cooler than that above sea. So, a breeze blows from land to sea and we call that land-breeze.
Question 8
A reliable measure of the degree of hotness or coldness of a body is called its_________
SOLUTION
Solution : C
Temperature is a measure of the degree of hotness or coldness of a body. It is proportional to the average kinetic energy of all the molecules present in an object. It is represented according to a comparative scale and is measured by a thermometer.
Question 9
A wooden spoon is dipped in a cup of ice cream. Its other end _____.
SOLUTION
Solution : D
The other end of wooden spoon does not become cold as wood is a poor conductor of heat and electricity and hence, it belongs to the category of insulators.
Question 10
The transition of a substance directly from the solid to the gaseous phase without passing through the intermediate liquid phase is known as
boiling
melting
sublimation
freezing
SOLUTION
Solution : C
Sublimation is a process where a solid turns into a gas without going through a liquid stage. Solid carbon dioxide which is more commonly known as "dry ice" sublimates at room temperature.