Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 31 to 35.
Magnets
A solid object that has the power to attract iron and some metals is called a magnet. It does this through its magnetic field, a region of force surrounding it. The (31) _______ the magnet, the more intense is the field.
Objects that are attracted to the magnet feel a force (32) _______ as magnetism when they are inside the magnetic field. This magnetic force can pass through some materials. Even a weak magnet will attract a pin to the other side of a sheet of paper, for example.
Magnets come in (33) _______ shapes. A familiar one is the curved horseshoes magnet. There are also bar magnets in the form of disc or a stubby cylinder. Every magnet has (34) _______ poles, called north and south, at opposite ends of it: at the two ends of a horseshoes magnet, for example, or on the two sides of a disc.
Powerful magnets can be made by passing an electric current through wire coiled around a piece of iron. The (35) _______ is called and electromagnet. Magnets are used in many household and everyday devices. They are also commonly used in industrial machinery, usually in the form of electromagnets.
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Thưởng th.10.2024
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