KIỂM TRA THƯỜNG XUYÊN KHTN 7

What is the term for motion that oscillates around a balance position?

• Motion.

• Oscillation.

• Wave.

• Repeating motion.

When flying, some insects like flies, mosquitoes, bees... produce buzzing sounds. Which explanation below is reasonable?

• Because they buzz while flying.

• Because they have special sound-producing organs.

• Because their breath is strong enough to produce sound.

• Because their small wings flap very quickly, creating oscillations and producing sound.

Through which environments can sound waves travel?

• Solid, liquid, gas.

• Solid, liquid, gas, vacuum.

• Solid, gas, vacuum.

• Liquid, gas, vacuum.

Why can't sound waves travel through a vacuum?

• Because a vacuum is an environment without mass.

• Because a vacuum is an environment without color.

• Because a vacuum is an environment without any matter.

• Because it is impossible to place a sound source in a vacuum.

Among the following motions, which one is not considered oscillation?

• A car driving straight on the road.

• A person sitting on a swinging hammock.

• The motion of a pendulum hanging from a moving train.

• The motion of two tuning forks when struck.

Which statement is correct regarding the frequency of oscillation?

• Frequency is the number of oscillations the object performs in 5 seconds.

• Frequency is the number of oscillations the object performs in 1 second.

• Frequency is the number of oscillations the object performs in 1 hour.

• Frequency is the number of oscillations the object performs in one day.

In 20s, a steel leaf performs 5000 oscillations. What is the frequency of the oscillation of the steel leaf?

• 500 Hz

• 20 Hz

• 250 Hz

• 100 000 Hz

What frequency range can the human ear hear?

• From 16 Hz to 160 Hz

• From 20 Hz to 20 000 Hz

• From 16 Hz to 160 000 Hz

• From 200 Hz to 20 000 Hz

What factors does the loudness of sound depend on?

• Pitch of the sound

• Frequency of sound oscillation

• Amplitude of oscillation

• Both B and C

Which of the following materials reflects sound poorly?

• Steel, wood, fabric

• Concrete, iron, cotton

• Stone, iron, steel

• Fabric, velvet, felt