A. the same speed as the wave energy
Answer:
1.171
Explanation:
if n₁sinΘ₁=n₂sinΘ₂, then n₂=n₁sinΘ₁ / sinΘ₂;

Answer:
60words/minute
Explanation:
If Sunitha can type 1800 words in half an hour, this can be expressed as;
1800 words = 30 minutes
To get her typing speed per minute, we will use the formula
Speed = Number of words/Time used
Typing speed = 1800/30
Typing speed = 60words/minute
Hence her typing speed in words per minute is 60words/minute
Answer:
30°
Explanation:
According to the second law of reflection, it States that the angle of incidence i is equal to the angle of reflection r.
The angle of incidence is known to be the angle between the incident ray and the normal.
The Angle of reflection is the angle between the reflected ray and the normal.
This normal ray is a ray that is perpendicular to the surface.
According to the question, if the beam of light is reflected off the surface and its angle of incidence is 30°, its angle of reflection will also be 30° i.e i=r = 30°
i thinkits an instrument called seismograph. not sure