Why does sound travel faster in water than in air?
A.
because water is a denser medium than air
B.
because air is a denser medium than water
C.
because water has a larger wavelength than air
D.
because air has a larger wavelength than water

a. Electric field strength is 1.6*10^6 V/m = 1.6 Megavolt/meter

b. speed of an electron is 5.2*10^14m/s

Explanation:

The electric field strength is given by:

E = ΔV/d

E = electric field strength,

ΔV = potential difference,

d = plate spacin

ΔV = 21×10^3V, d = 1.3×10^-2m

a) E = V / d = (21*10^3)/(1.3×10^-2) = 1.6*10^6 V/m = 1.6 Megavolt/meter

b) Exit energy = V . e

Where 'e' is the charge of electron (1.6 * 10^(-19)

Exit energy = (21*10^3)*(1.6*10^-19) = 3.36*10−15

From the above, speed v = √2*Exit Energy/mass

Where 'm' is the mass of electron (9.1 * 10^(-31)

v = √2*energy/mass

v = √2*(3.36*10^-15)/(9.1*10^-31) = 5.2*10^14m/s