B, ensjsnsjdjsncnxnsndnxbsndbx
Answer:
7.402%
Explanation:
Given that the total electrical energy used by the bulb in every second is 66.2 J.
The useful energy converted to light energy is 4.9 J.
As efficiancy (in %) = (Useful energy)/(Total energy) x 100
So, the efficiency of the bulb = (4.9/66.2)x100=7.402%
Hence, the efficiency of the bulb is 7.402%.
Given the index of refraction, n and speed of light in the vacuum, c, we can solve for the speed of light in the transparent substance by the equation below.
n = c / v
where v is our unknown.
Substituting the known values,
1.7 = (3 x 10^8 m/s) / v
The value of v is equal to 1.76 x 10^8 m/s.
The force of Earth's gravity on you is greatest when you stand as
close as you can to the center of the Earth (but not underground).
From the choices listed, that would be (c).