Step 1: Look in your book or online for the conical pendulum equation.
Step 2: Look at the drawing and see which angle is involved in the equation.
Answer: It's Angle #2 in your drawing.
Answer:
Explanation:
The angle of incidence and refraction are both measured from the normal
angle of incidence = 30°
angle of refraction = 23°
refractive index(n) = sini / sinr
n = sin30°/sin23°
n = 1.27965
refractive index (n) = 1/sinC
where C is the critical angle.
sinC= 1/n
C =arcsin (1/n)
C =arcsin (1/1.27965)
C = 51.39°
Longitudinal waves....
sounds propagates through moving waves of compression and ratification of a medium which allows longitudinal propagation
Explanation:
It is given that,
Voltage, 
De broglie wavelength in terms of voltage is given by :

m and e are the mass and charge on electron. So,



So, the De broglie wavelength of an electron is 1.53 meters. Hence, this is the required solution.