Answer:
λ = 1360 m
Explanation:
Given data:
frequency of driving nails is given as 1 stroke per second mean at every 0.25 sec she hit the nails
speed of sound is given as 340 m/s
we know that the wave equation is given as
Speed = frequency × wavelength,
v = f × λ
where,
v = speed in meters/second (m/s)
f = frequency in Hertz (Hz)
substituing value to get wavelength of her driving nails


λ = 1360 m
Answer:
B. Maximum velocity of ejected electrons.
Explanation:
The ejection of electrons form a metal surface when the metal surface is exposed to a monochromatic electromagnetic wave of sufficiently short wavelength or higher frequency (or equivalently, above a threshold frequency), which leads to the enough energy of the wave to incident and get absorbed to the exposed surface emits electrons. This phenomenon is known as the photoelectric effect or photo-emission.
The minimum amount of energy required by a metal surface to eject an electron from its surface is called work function of metal surface.
The electrons thus emitted are called photo-electrons.
The current produced as a result is called photo electricity.
Energy of photon is given by:

where:
h = Planck's constant
frequency of the incident radiation.
CORRECT ANSWER:
d. Anywhere from days to thousands of years.
STEP-BY-STEP EXPLANATION:
The whole question from book is
How long do molecules of groundwater stay in the
ground?
a. Days
b. Weeks
c. Months
d. Anywhere from days to thousands of years
Explanation:
solution: mass m = 5g = 0.005kg; extension e = 7cm = 0.07m; force f = 70 N; velocity = ?; using: work done in elastic material w = 1/2 fe = 1/2 ke2 = 1/2 mv2 - the kinetic energy of the moving stone. 1/2 fe =...