1. Question 1 of 25

   An electric iron or heater gets hot because of

   A Magnetic effect B Chemical effect only C Heating effect of electric current D Radiation from the Sun
2. Question 2 of 25

   Chlorofluorocarbons (CFCs) used in older refrigerators are harmful because they

   A Cause fires B Cause floods C Deplete the ozone layer D Increase oxygen
3. Question 3 of 25

   Wearing black clothes in summer is uncomfortable because black surfaces

   A Reflect more heat B Absorb more heat radiation C Conduct more electricity D Emit no heat
4. Question 4 of 25

   A thermostat in a geyser or iron

   A Increases voltage B Stores heat C Switches the heating off when the set temperature is reached D Reduces the water pressure
5. Question 5 of 25

   A thermos flask keeps liquids hot or cold because

   A It generates heat B The vacuum between double walls reduces conduction and convection C It has a heavy lid only D It contains a heater
6. Question 6 of 25

   Heat from a hot stove reaches your hand held above it mainly by

   A Convection and radiation B Conduction through air only C Sound waves D Magnetism
7. Question 7 of 25

   A desert (evaporative) cooler works best in

   A Humid weather B Cold weather C Rainy weather D Hot and dry weather
8. Question 8 of 25

   The heating element of an electric heater is made of

   A Copper B Iron C Nichrome D Aluminium
9. Question 9 of 25

   Wooden or plastic handles on pots are used because they are

   A Poor conductors (insulators) of heat B Good conductors C Magnetic D Heavy
10. Question 10 of 25

    A ceiling fan makes us feel cooler mainly because it

    A Increases evaporation of sweat and heat loss from the skin B Cools the air C Removes carbon dioxide D Makes air heavier
11. Question 11 of 25

    Double-glazed windows save heating and cooling energy because

    A Glass is thicker B The air gap between two panes reduces heat transfer C They reflect all heat D They are painted
12. Question 12 of 25

    Metal cooking pots are used because metals are good

    A Insulators B Absorbers of sound C Reflectors of light only D Conductors of heat
13. Question 13 of 25

    A solar water heater uses

    A Electricity only B Gas only C Sunlight absorbed by a black collector D Wind power
14. Question 14 of 25

    A room air conditioner cools the room by

    A Creating cold air from nothing B Adding water vapour C Burning gas D Removing heat and moisture from indoor air and releasing it outside
15. Question 15 of 25

    The coolant (refrigerant) widely used in modern domestic refrigerators for its low environmental impact is

    A CFC-12 B Water C Oxygen D Isobutane (R-600a)
16. Question 16 of 25

    The normal temperature inside the fresh-food compartment of a refrigerator is about

    A 20 to 25 degrees Celsius B -30 degrees Celsius C 10 to 15 degrees Celsius D 3 to 5 degrees Celsius
17. Question 17 of 25

    One 'ton' of air-conditioning capacity equals about

    A 1,200 BTU per hour B 12,000 BTU per hour C 120 BTU per hour D 1,200,000 BTU per hour
18. Question 18 of 25

    In the evaporator of a refrigerator, the refrigerant

    A Condenses and releases heat B Evaporates and absorbs heat C Freezes D Turns into water
19. Question 19 of 25

    A refrigerator keeps food cool by

    A Adding cold from outside B Burning gas C Removing heat from the inside and releasing it outside D Blowing hot air in
20. Question 20 of 25

    The coils at the back of a refrigerator are called the

    A Condenser B Evaporator C Compressor D Thermostat
21. Question 21 of 25

    Ice formation in the freezer reduces efficiency because ice

    A Acts as an insulator and reduces heat transfer B Increases temperature C Produces heat D Blocks light
22. Question 22 of 25

    The part of a refrigerator that circulates and compresses the refrigerant is the

    A Condenser B Compressor C Capillary tube D Door seal
23. Question 23 of 25

    A gas stove should have the burner flame blue, which means

    A Complete combustion B Incomplete combustion C No combustion D Low heat
24. Question 24 of 25

    Food cooks in a microwave oven mainly by

    A Vibrating water molecules with microwaves B Burning gas C Direct flames D Infrared lamps only
25. Question 25 of 25

    The main purpose of an inverter air conditioner is to

    A Invert the room temperature B Produce DC power C Increase the noise D Vary the compressor speed to save electricity

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