I'd say ground. <span>Voltage in the US is 110-120 volts while in other countries it is 220-240 volts. if you have a 110-120 volt appliance, you need a step-up transformer (110 to 220)before you could use it in a 220 volt power supply.</span>
When light moves from a medium with higher refractive index to a medium with lower refractive index, the critical angle is the angle above which there is no refracted ray, and it is given by:

(2)
where

is the refractive index of the second medium and

is the refractive index of the first medium.
We can find the ratio

by using Snell's law:

(1)
where

is the angle of incidence

is the angle of refraction
By using the data of the problem and re-arranging (1), we find

and if we use eq.(2) we can now find the value of the critical angle:
Answer:
13.7m
Explanation:
Since there's no external force acting on the astronaut or the satellite, the momentum must be conserved before and after the push. Since both are at rest before, momentum is 0.
After the push

Where
is the mass of the astronaut,
is the mass of the satellite,
is the speed of the satellite. We can calculate the speed
of the astronaut:

So the astronaut has a opposite direction with the satellite motion, which is further away from the shuttle. Since it takes 7.5 s for the astronaut to make contact with the shuttle, the distance would be
d = vt = 1.83 * 7.5 = 13.7 m
Answer:
beats per second
Explanation:
Number of heart beats = 
time taken = 
now we have
%
%
now rate of heart beat is defined as number of heart beat per unit of time
so we have


so we have

%
beats per second