PHYSICS [1 Mark Question Answer]

Air is most non-conducting.

Among all the metals, Silver is most conducting.

Gases are the worst conductor of heat.

Metals are the best conductor of heat.

No, liquids are poor conductors of heat.

Good conductor allow heat to pass through them easily while bad conductor of heat does not allow heat to pass them.

Thermal insulation means restriction of transfer of heat by any means.

No, conduction is not possible in vacuum.

Global warming occurs due to the presence of carbon dioxide, CFCs, methane in the atmosphere. Carbon dioxide acts as a transparent gas to incoming shortwave radiations which the earth re-radiates into space. It, therefore, traps the outgoing longwave radiations thus warming the lower atmosphere of the earth thereby causing global warming.

As fossil fuels are non-renewable sources of energy they are not available again and again if are fully exhausted, so they should not be used extensively.

Carbon dioxide, Carbon monoxide, methane are greenhouse gases.

The process of conduction involves the transmission of heat from the hot end to the cold end from particle to particle of the medium.

WHO is World Health Organization which put a check on diseases and global warming etc.

UV means an ultraviolet range of radiations. These are the radiations which are emitted by the sun and they enter our atmosphere.

CFC means Chlorofluorocarbons which are produced mainly by refrigeration industries, aerosol cans, coolants, propellants, and plastic foams. They cause global warming.

As loss of heat takes place by Radiation and the process of radiation does not require any material medium, so there is no role of air in loss of heat.

The ball will lose the minimum amount of heat if it is polished.

As no material medium surrounds the ball so there is no possibility of losing heat by conduction or convection. The ball will lose heat by Radiation.

Heat loss due to radiation can be minimized by polishing the surface as polished surfaces radiate less heat.

As conduction requires a medium for transfer of heat so heat loss due to conduction can be minimized if the substance is kept away from any material medium.

As convection requires medium for transfer of heat so heat loss due to convection can be minimized if the substance is kept away from any material medium.

The temperature in a greenhouse rises because heat enters the house through the glass but cannot escape out, because the glass reflects the heat back to the inside of the house. This makes the glasshouse warmer than the outside environment.

The greenhouse is a glasshouse constructed to keep delicate and rare plants that require warmth and protection from the weather. It is constructed by panels of glass.

Heat radiation travels with the speed of light and always follows a straight path.

The radiating power of a surface can be increased by blackening it.

We receive heat from the sun by the process of Radiation.

Conduction, convection, and radiation are three modes of transfer of heat.

As earth surface gets heated by sun rays and due to process of convection the air near earth surface open to sunlight get heated while in shade sun rays does not fall on earth surface so air near that surface would not heat up.

Inside the refrigerator, cooling takes place by convection. The freezing chamber at the top produces cool and heavy air which descends and hot air from below goes up setting convection current. Thus, cooling in a refrigerator is kept near the top.

Conduction is not possible in Vacuum because process of conduction require a material medium for transfer of heat.

In the process of convection heat is transferred from one point to another by actual movement of particles of medium and particles of solid cannot move so the process of convection is not possible in case of solids.

Water is heated generally from below because water itself is a bad conductor of heat and the transfer of heat through convection take place vertically upwards

Order of increasing heat conductivity:
Air < water< mercury < copper.

In cold countries, windows are provided with two glass panes because in between these two glass panes, a thin layer of air is present: air being a bad conductor obstructs the conduction of heat from the room to outside.

Mercury is good conductor of heat.

Brick is a bad conductor of heat, hence bricks greatly reduce the conduction of heat from outside to the room. In order to ensure better insulation, bricks are made hollow so that air-filled between these gaps provides insulation to heat.

Cooking utensils are made up of metals because metals are good conductors of heat and they easily allow the heat to pass through them.

Yes, this is a correct statement. Ebonite and asbestos are worst conductor of heat.

No, air is not a good conductor of heat.

The clinical thermometer is a specially designed thermometer used to measure the temperature of a human body easily and as accurately as possible.

Before constructing a thermometer, we determine lower fixed point and upper fixed point and divide the whole range of thermometer into specific number of equal divisions to provide a scale for measuring the temperatures within a range.

Fahrenheit designed the first thermometer.

The usual range of temperature marked on the clinical thermometer is 95° F to 110°F.

Mercury is the liquid used in a clinical thermometer

Range of thermometer is the range of temperature which can be measured by thermometer.

Thermometer works on the principal that substances expand when heated and contract on cooling.

The thermometer is used for measuring the temperature of a body.

Relation between Celsius and Fahrenheit scales of temperature is
C/100 = (F - 32)/180.