Class 7 Science Chapter 4 MCQ for 2020-21
Class: | 7 |
Subject: | Science |
Contents: | Multiple Choice Questions – MCQ Tests |
Class 7 Science Chapter 4 MCQ Tests for 2020-21
Class 7 Science Chapter 4 MCQ are given below with explanation of each answer. There are sufficient number of tests to practice chapter 4 of 7th Science. These tests make a student confident about the concepts related to standard 7 Science. Give test and practice with important questions if required. If you have more questions to ask, please visit to Discussion Forum.
Q1
In which of the statement is or are correct about “thermometer”?
[A]. Don’t hold the thermometer by the bulb
[B]. Don’t washed thermometer by any liquid
[C]. Don’t jerks the thermometer before use
[D]. Don’t use clinical thermometer for the person who works in sunlight
Answer: Option A
Explanation:We are advised not to hold the thermometer bulb while reading it, as the level of mercury increases from the actual reading due to our body temperature.
Q2
Cooking utensils are made of metals because they are
[A]. Durable
[B]. Malleable
[C]. Good conductors of heat
[D]. Do not break on heating
Answer: Option C
Explanation:We know that metals are good conductors of heat and electricity. Generally, in cooking utensils are made of metals because they are good conductors of heat. Here, option [C] is best suitable for this question.
Q3
Conviction may occur through
[A]. Solids, liquids
[B]. Liquids, gases
[C]. Solids, gases
[D]. Solids, liquids, gases
Answer: Option B
Explanation:Convection occurs when particles with a lot of heat energy in a liquid or gas move and take the place of particles with less heat energy. Heat energy is transferred from hot places to cooler places by convection. Heat energy is transferred from hot places to cooler places by convection. Hence, your answer will be option [B].
Q4
Which of the following statement is or are incorrect?
[A]. Mercury expands easily on heating.
[B]. Mercury is easily visible being shining and opaque.
[C]. Mercury is considered as toxic substance.
[D]. Mercury is the liquid (non-metal)
Answer: Option D
Explanation:Mercury is the only metal which is found in liquid state at room temperature. Rest all are correct. Hence, your answer will be option [D].
Q5
In which of the following statement is or are incorrect?
[A]. Heat is a form of energy.
[B]. Heat flows from one object to another object when there is a difference in temperature.
[C]. In the transmission of heat total amount of heat remains unchanged.
[D]. None of the above
Answer: Option D
Explanation:Here, all the statements are correct about “Heat”. Hence, your answer will be option [D].
Q6
In which of the statement is or are correct?
[A]. Doctor’s thermometer is a device which measures our body temperature.
[B]. The maximum-minimum is a device which measures the temperature of any objects.
[C]. Laboratory thermometer is used to measure the temperature of laboratory objects.
[D]. None of the above
Answer: Option A
Explanation:Clinical thermometers or doctor’s thermometer is a device which measures our body temperature. Rest all are incorrect. Hence, your answer will be option [A].
Q7
Wooden spoon is dipped in a cup of ice cream. Its other end
[A]. Becomes cold by the process of conduction
[B]. Becomes cold by the process of convection
[C]. Becomes cold by the process of radiation
[D]. Does not become cold
Answer: Option D
Explanation:We know that wood is non-conductor of heat or cold. It acts as an insulator. So, when wooden spoon is dipped in a cup of ice cream its other end does not become cold. Hence, your answer will be option [D].
Q8
Boojho has three thermometers. He wants to measure the temperature of his body and that of boiling water. Which thermometer(s) should he choose?
[A]. Clinical thermometer for measuring body tem. and laboratory thermometer for measuring the tem. of boiling water
[B]. Clinical thermometer for measuring temperature of both.
[C]. Laboratory thermometer for measuring temperature of both.
[D]. Digital thermometer for measuring temperature of both.
Answer: Option A
Explanation:Clinical thermometer and digital thermometer are used to measure body temperature and laboratory thermometer is used to measure the temperature of boiling water or any object other than human body.
Q9
Once in a summer day, Paheli keeps an iron chair in sunlight. After few hours, iron chair gets heated because
[A]. Heat is transferred by conduction
[B]. Heat is transferred by convection
[C]. Heat is transferred by radiation
[D]. Heat is transferred by all the process
Answer: Option C
Explanation:The transfer of heat by radiation does not require any medium. It can take place whether a medium is present or not. From the sun the heat comes to us by this process which is known as radiation. When we sit in front of a room heater, we get heat by this process. All the objects are heated from the rays of sun by this process.
Q10
At a campsite there are tents of three shades. One made with black fabric and other is white fabric and one is black and white combination. Which will you prefer for resting on a hot summer afternoon?
[A]. Black fabric
[B]. White fabric
[C]. Combination of both
[D]. None of the above.
Answer: Option B
Explanation:We will prefer white fabric tent in case of summer because it reflects all the radiations from the sun and keeps us cool inside the tent.
Thermos flask
Thermos flask is a special type of vessel which keeps hot liquids hot and cold liquids cold. It is made in such a way as to reduce the loss of heat by conduction, convection and radiation to minimum. It is a double walled glass vessel. The space between the two walls has no air in it. It is a vacuum indeed. The inside of the outer wall and outside of the inner wall are brightly polished with silver. The whole system is enclosed in a metal case. It is supported on corks or rubber pieces on all sides. The mouth too is closed with a cork.
How it Works
The vacuum between the walls prevents the flow of heat of conduction and convection. As for radiation, the brightly polished outer surface of the inner wall is a slow radiator of heat. The little heat that radiates is reflected back by the inner brighter surface of the outer wall. So, the hot liquid remains hot for a long time in the flask.
What is thermometer?
The device which measures the degree of hotness is called thermometer.
Which type of surfaces are good absorbers of heat?
Black and rough surfaces are good absorbers of heat.
Which type of surfaces are poor absorbers of heat?
White and smooth surfaces are poor absorbers of heat.
Which scale is used for measuring heat in scientific work?
Temperature is generally measured in Celsius or Fahrenheit scale. Kelvin scale is used for scientific work.