The right answer is B. hope this helps you :)
It is itself. This question does not make sense.
Answer:
The magnitude of gravitational force between two masses is
.
Explanation:
Given that,
Mass of first lead ball, 
Mass of the other lead ball, 
The center of a large ball is separated by 0.057 m from the center of a small ball, r = 0.057 m
We need to find the magnitude of the gravitational force between the masses. It is given by the formula of the gravitational force. It is given by :

So, the magnitude of gravitational force between two masses is
. Hence, this is the required solution.
Answer:
Liquid's index of refraction, n₁ = 1.27
Explanation:
It is given that,
The critical angle for a liquid in air is, 
We have to find the refractive index of the liquid. Critical angle of a liquid is defined as the angle of incidence in denser medium for which the angle of refraction is 90°.
Using Snell's law as :

Here, 

Where
n₂ = Refractive index of air = 1
n₁ = refractive index of liquid
So,


n₁ = 1.269
or n₁ = 1.27
Hence, the refractive index of liquid is 1.27