Podcast
Questions and Answers
In a solid material, heat is primarily transferred through:
In a solid material, heat is primarily transferred through:
What does the slope of a velocity vs. time graph represent?
What does the slope of a velocity vs. time graph represent?
If the frequency of a wave increases while its speed remains constant, what happens to the wavelength?
If the frequency of a wave increases while its speed remains constant, what happens to the wavelength?
Which of the following is an example of a mechanical wave?
Which of the following is an example of a mechanical wave?
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In which medium does sound travel the fastest?
In which medium does sound travel the fastest?
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Which of the following electromagnetic waves has the highest frequency?
Which of the following electromagnetic waves has the highest frequency?
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What happens when two like charges are brought together?
What happens when two like charges are brought together?
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How can a material become positively charged?
How can a material become positively charged?
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If you comb your hair and the comb becomes positively charged, what happens to your hair?
If you comb your hair and the comb becomes positively charged, what happens to your hair?
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Which of the following can be attracted by a positively charged object?
Which of the following can be attracted by a positively charged object?
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What happens when two uncharged objects are brought close together?
What happens when two uncharged objects are brought close together?
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Study Notes
Heat Transfer
- Heat travels from a region of higher temperature to a region of lower temperature.
- Heat can travel through a pan by conduction.
- Heat can travel through soup by convection.
Graph Analysis
- The slope of a distance vs time graph represents speed.
- The slope of a speed vs time graph represents acceleration.
Waves
- As the frequency of a wave increases and its speed remains constant, the wavelength decreases.
- The speed of a wave can be calculated by the formula: speed = wavelength x frequency.
- The speed of a wave in a lake can be calculated if the wavelength and frequency are known.
Electromagnetic Waves
- Energy from the sun reaches the earth through electromagnetic waves.
- Electromagnetic waves include infrared, ultraviolet, and X-ray waves, but not sound waves.
- Electromagnetic waves have different frequencies, with X-ray having the highest frequency.
Sound Waves
- Sound waves are produced through compression and rarefaction of molecules.
- The speed of sound increases in a sequence of media: air, wood, water, metal, and ice.
Electromagnetic Spectrum
- The electromagnetic spectrum includes infrared, ultraviolet, X-ray, and radio waves.
- Sound waves are not part of the electromagnetic spectrum.
Electricity
- Like charges repel each other.
- A material can become positively charged by losing electrons.
- When a comb becomes positively charged, hair will be attracted to it because hair becomes negatively charged.
- Positively charged objects can attract neutral objects.
Light
- Red light and violet light travel at the same speed in a vacuum.
- Red light has a longer wavelength than violet light.
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Description
This quiz is a post-test for Grade 7 Science students covering topics like electric charges and their behavior. Answer questions related to charge interactions and their effects on each other. Test your knowledge with multiple-choice questions and see how well you understand the concepts.
