“Wave-B is every bit as invisible as Wave-A is.”
Answer:
The correct answer is B.
The astronaut will know due to the light from the explosion.
Explanation:
Sound and vibrations require a medium such as air to travel through. Space, there is no air. Only a vacuum. So sound and vibrations are unable to travel. Light requires no medium to travel. It can go through a vacuum.
Therefore the Astronaut will see a bright flash of light as it travels from the explosion to outer space. It is also important to note that light can travel very far because nothing else interacts with its wave particles and as such, it cannot be impeded.
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In a quarter of an hour it will travel 1/4 x 90 = 22.5Km
Answer:
True
Explanation:
A concave mirror produces real and inverted image when object placed at different locations beyond focus of the mirror.
A concave mirror produces virtual and erect and magnified image when an object placed between focus and the pole of the mirror.