A 1-m-tall barrel is closed on top except for a thin pipe extending 4.2 m up from the top. When the barrel is filled with water
1 answer:
Answer:
P = 52 kPa
Explanation:
Hidrostatic pressure is defined as the product of the height of liquid (h) by its specific weight (ρ) and by the acceleration of gravity (g).
In the first scenario, the atmospheric pressure is:
In the second scenario, h = 4.2 + 1 m. Therefore, the pressure at the bottom of the barrel is:
The pressure on the bottom when water is added to fill the pipe to its top is 52 kPa.
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a) Zinc (work function: 4.3 eV)
The equation for the photoelectric effect is:
(1)
where
is the energy of the incident photon, with
h = Planck constant
c = speed of light
= wavelength
= work function of the metal
K = maximum kinetic energy of the photoelectrons emitted
The stopping potential (V) is the potential needed to stop the photoelectrons with maximum kinetic energy: so, the corresponding electric potential energy must be equal to the maximum kinetic energy,
So we can rewrite (1) as
where we have:
V = 1.93 V
e is the electron charge
First of all, let's find the energy of the incident photon:
Converting into electronvolts,
And now we can solve eq.(1) to find the work function of the metal:
so, the metal is most likely zinc, which has a work function of 4.3 eV.
b) The stopping potential is still 1.93 V
Explanation:
The intensity of the incident light is proportional to the number of photons hitting the surface of the metal. However, the energy of the photons depends only on their frequency, so it does not depend on the intensity of the light. This means that the term E in eq.(1) does not change.
Moreover, the work function of the metal is also constant, since it depends only on the properties of the material: so is also constant in the equation. As a result, the term (eV) must also be constant, and therefore V, the stopping potential, is constant as well.
The range of potential energies of the wire-field system for different orientations of the circle are -
θ U
0° 375 π x
90° 0
180° - 375 π x
We have current carrying wire in a form of a circle placed in a uniform magnetic field.
We have to the range of potential energies of the wire-field system for different orientations of the circle.
<h3>What is the formula to calculate the Magnetic Potential Energy?</h3>The formula to calculate the magnetic potential energy is -
U = M.B = MB cos
where -
M is the Dipole Moment.
B is the Magnetic Field Intensity.
According to the question, we have -
U = M.B = MB cos
We can write M = IA (I is current and A is cross sectional Area)
U = IAB cos
U = IπB cos
For = 0° →
U(Max) = MB cos(0) = MB = IπB = 5 × π ×
× 3 ×
=
375 π x .
For = 90° →
U = MB cos (90) = 0
For = 180° →
U(Min) = MB cos(0) = - MB = - IπB = - 5 × π ×
× 3 ×
=
- 375 π x .
Hence, the range of potential energies of the wire-field system for different orientations of the circle are -
θ U
0° 375 π x
90° 0
180° - 375 π x
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Answer:
x = 45 cm
Explanation:
Given that,
The length of a rod, L = 50 cm
Mass, m₁ = 0.2 kg
It is at 40cm from the left end of the rod.
We need to find the distance from the left end of the rod should a 0.6kg mass be hung to balance the rod.
The centre of mass of the rod is at 25 cm.
Taking moments of both masses such that,
The distance from the left end is 40+5 = 45 cm.
Hence, at a distance of 45 cm from the left end it will balance the rod.