12. Which energy transformation occurs in an electric iron?
A. heat to light
C. heat to electricity
B. light to heat
D. electricity to heat
13. What form of energy is used by farmers to dry their crops without a cost?
A. Solar energy
C. Chemical energy
B. Sound energy
D. Electrical energy
D. Electric stove
14. Which of these objects below produce sound?
A. Doorbell B. Flat iron
C. Rice cooker
15. Which of the following DOES NOT release heat to the environment?
A. burning paper
C. water in a pail
B. boiling water
D. turning on the radio
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16. Which of the following shows that electrical energy is transformed into sound
energy?
A. playing the electric guitar
B. using sunlight to dry clothes
C, switching on incandescent light.
D. an athlete running after drinking
17. Why is sound used for taking pictures of babies inside the womb?
A. Sound is the least harmful among sound, light and heat.
B. The babies inside the womb can already hear sounds, but cannot see yet.
C. Light will not pass through the mother's skin and flesh, while heat will just
be absorbed and will not be reflected.
D. Sound can be transmitted safely through human tissues and fluids, and can
be reflected back to be used for imaging.
18. Sound travel FASTEST through which medium?
A. Gas
B. Solid
C. Liquid
D. Empty space
19. Which of the following shows a change from light energy to heat energy?
A. Boiling of water
C. warming of beach sand
B. Buzzing of bees
D. answering a phone call
20. A certain appliance underwent energy transformation as shown. What is this
appliance?
Electrical energy light energy sound energy heat
A. Laptop
B. flat iron
C. electric fan
D. microwave oven​