Answer:
PE=0.29J
Explanation:
According to the description, there is a angle and in point swung upward of 70°
So,

Appling the equation of Potential Energy we have,

Answer:
1.97 x 10^8 m/s
Explanation:
refractive index of crown glass with respect to air, n = 1.52
speed of light in air, c = 3 x 10^8 m/s
Let v be the speed of light in crown glass.
By use of the definition of refractive index

where, n be the refractive index of crown glass, c be the speed of light in vacuum and v be the speed of light in crown glass


v = 1.97 x 10^8 m/s
Thus, the speed of light in crown glass is 1.97 x 10^8 m/s.
As per question the initial states of the gases are given as
INITIAL STATE: FINAL STATE:
![v_{2} =3v[say]](https://tex.z-dn.net/?f=v_%7B2%7D%20%3D3v%5Bsay%5D)

AS per combined gas equation obtained from the combination of Boyle's law and Charles law [Basic ideal gas laws]

Hence 
=
=190.3 K [ANS]