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9. Some sunglasses have photochromic lenses - Edexcel - GCSE Physics - Question 9 - 2019 - Paper 1
Question 9
9. Some sunglasses have photochromic lenses. Photochromic lenses are clear when the lenses are indoors but they darken in bright sunlight to reduce the effects of t... show full transcript
Worked Solution & Example Answer:9. Some sunglasses have photochromic lenses - Edexcel - GCSE Physics - Question 9 - 2019 - Paper 1
Step 1
Suggest a benefit of making the lenses go dark with ultraviolet light.
Answer
One benefit of photochromic lenses darkening in response to ultraviolet (UV) light is that they provide enhanced protection for the eyes. By reducing the amount of light entering the eyes, these lenses help to minimize glare and reduce eye strain in bright conditions. Additionally, they can help protect against UV radiation, which can cause long-term damage to the eyes, such as cataracts and macular degeneration.
Step 2
Calculate how many times further it is from Earth to Jupiter than from Earth to the Sun.
Answer
To find how many times further it is from Earth to Jupiter than from Earth to the Sun, we can use the times taken for the radio waves as a measure of distance.
- The time taken for light waves from the Sun to reach Earth is 8 minutes.
- The time taken for radio waves from Jupiter to reach Earth is 40 minutes.
To calculate the ratio: ext{Distance Ratio} = rac{ ext{Time from Jupiter}}{ ext{Time from Sun}} = rac{40 ext{ minutes}}{8 ext{ minutes}} = 5
Thus, it is 5 times further from Earth to Jupiter than from Earth to the Sun.
Step 3
State the property of electromagnetic radiation that is used in your answer.
Answer
The property of electromagnetic radiation used in the answer is the relationship between distance and time; specifically, the speed of light. Since all electromagnetic waves, including light and radio waves, travel at the speed of light in a vacuum, the time taken for these waves to reach an observer allows us to calculate the distance.