As the speed is a scalar quantity as it has the only magnitude in it. Therefore, the average speed is also stated as a scalar quantity.
Hence, the correct answer is (B)
Answer:
I'm guessing it would remain a mystery to us all
When light travels from a medium with higher refractive index to a medium with lower refractive index, the critical angle is the angle of incidence above which light is reflected only (no refraction occurs), and the value of this critical angle is given by

where n2 is the refractive index of the second medium and n1 is the refractive index of the first medium.
In this problem, the first medium is the glass (

), while the second medium is oil (

), therefore the critical angle is given by
Explanation:
Parameters
Number of oscillation = 40 oscillations
Time of oscillation = 128s
Formular
Period (T) = <u>No of oscillation</u>
Time taken
T = <u>128</u>
40
T=3.2s
Here is the answer that would best complete the given statement above. To calculate the dashed orbits from the stellar positions, astronomers had to assume that <span>if they observed for many more years, the dots would trace out ellipses. Hope this is the answer that you are looking for. </span>