85 decibels or higher can cause damage to the human ear.
Decibels is the value of the measurement of sound. Hearing loss can be caused
by noise coming from a loud sound. Noise induced hearing loss maybe permanent
loss or temporary loss. Examples of activities that can give you a noise induced
hearing loss is target shooting, listening to music in your earphones that have
a high volume, and using lawnmowers.
The speed of the spaceship relative to the galaxy is 0.99999995c.
A light-year measures distance rather than time (as the name might imply). A light-year is a distance a light beam travels in one year on Earth, which is roughly 6 trillion miles (9.7 trillion kilometers). One light-year equals 5,878,625,370,000 miles. Light moves at a speed of 670,616,629 mph (1,079,252,849 km/h) in a vacuum.We multiply this speed by the number of hours in a year to calculate the distance of a light-year (8,766).
The Milky way galaxy is 100,000 light years in diameter.
The galaxy's diameter is a mere 1. 0 ly.
We know that ;

L = 1 light year
L₀ = 100,000 light year




Therefore, the speed of the spaceship relative to the galaxy is 0.99999995c.
Learn more about a light year here:
brainly.com/question/17423632
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Answer:
1.30
Explanation:
To calculate the critical angle we have ti use the formula:

where theta_c is the critical angle, n1 is the index of refraction of the material where the light is totally reflected, and n2 is the refractive index of the other material.
By taking n_2 and replacing we obtain:

hope this helps!!
Just show a picture so I can help ur information is misleading...