Answer:
359 m/s
Explanation:
Highest frequency a person can hear is 20,000Hz.
f = c × λ
Frequency = Wave speed × Wavelength
Wavelength = 20,000 ÷ 343 = 58.31m
Wavespeed = Frequency ÷ Wavelength
c = 20,950 ÷ 58.31 = 359.3 m/s
= 359 m/s (3 s.f.)
If a ray of light hits the surface of a sheet of glass, some light will be reflected by the surface of the glass. However, much of the light will pass through the glass, because glass is transparent. ... This 'bending of a ray of light' when it passes from one substance into another substance is called refraction.
On the whole, the metals burn in oxygen to form a simple metal oxide. Beryllium is reluctant to burn unless it is in the form of dust or powder. Beryllium has a very strong (but very thin) layer of beryllium oxide on its surface, and this prevents any new oxygen getting at the underlying beryllium to react with it.
Answer:
Explanation:
Given
Force 
time interval 
Impulse is given by 
For two significant Figure
Answer:
The uncertainty in momentum changes by a factor of 1/2.
Explanation:
By Heisenberg's uncertainty principle, ΔpΔx ≥ h/2π where Δp = uncertainty in momentum and Δx = uncertainty in position = 0.2 nm. The uncertainty in momentum is thus Δp ≥ h/2πΔx. If the uncertainty in position is doubled, that is Δx₁ = 2Δx = 0.4 nm, the uncertainty in momentum Δp₁ now becomes Δp₁ ≥ h/2πΔx₁ = h/2π(2Δx) = (h/2πΔx)/2 = Δp/2.
So, the uncertainty in momentum changes by a factor of 1/2.
