Answer:
![523269.9\ \text{N/m}](https://tex.z-dn.net/?f=523269.9%5C%20%5Ctext%7BN%2Fm%7D)
Explanation:
q = Charge
r = Distance
![q_1=25\ \text{C}](https://tex.z-dn.net/?f=q_1%3D25%5C%20%5Ctext%7BC%7D)
![r_1=3000\ \text{m}](https://tex.z-dn.net/?f=r_1%3D3000%5C%20%5Ctext%7Bm%7D)
![q_2=40\ \text{C}](https://tex.z-dn.net/?f=q_2%3D40%5C%20%5Ctext%7BC%7D)
![r_2=850\ \text{m}](https://tex.z-dn.net/?f=r_2%3D850%5C%20%5Ctext%7Bm%7D)
The electric field is given by
![E=E_1+E_1\\\Rightarrow E=k(\dfrac{q_1}{r_1^2}+\dfrac{q_2}{r_2^2})\\\Rightarrow E=9\times 10^9\times (\dfrac{25}{3000^2}+\dfrac{40}{850^2})\\\Rightarrow E=523269.9\ \text{N/m}](https://tex.z-dn.net/?f=E%3DE_1%2BE_1%5C%5C%5CRightarrow%20E%3Dk%28%5Cdfrac%7Bq_1%7D%7Br_1%5E2%7D%2B%5Cdfrac%7Bq_2%7D%7Br_2%5E2%7D%29%5C%5C%5CRightarrow%20E%3D9%5Ctimes%2010%5E9%5Ctimes%20%28%5Cdfrac%7B25%7D%7B3000%5E2%7D%2B%5Cdfrac%7B40%7D%7B850%5E2%7D%29%5C%5C%5CRightarrow%20E%3D523269.9%5C%20%5Ctext%7BN%2Fm%7D)
The electric field at the aircraft is ![523269.9\ \text{N/m}](https://tex.z-dn.net/?f=523269.9%5C%20%5Ctext%7BN%2Fm%7D)
Answer:
1. a
2. b
3. b
Explanation:
1.
Resistance is the property of a conductor to offer resistance to the flow of current. The lower the resistance better is the conductivity of wire.
We know that the resistance of a wire depends on several factor which are inter-connected by an equation as:
where:
R = resistance of the wire
length of the wire
cross sectional area of the wire
from the above relation we observe that
![R\propto \frac{1}{a}](https://tex.z-dn.net/?f=R%5Cpropto%20%5Cfrac%7B1%7D%7Ba%7D)
- Also when the temperature of the wire is significantly high then the lattice vibration cause obstruction in the path of the flowing charges and reduce the current flow.
2.
As the collision between the electrons and protons increases the speed of the flow of charges will decrease because the opposite charges attract each other and as we know that electrical current is the rate of flow of charge.
3.
Heating up of wire due to sunlight will cause lattice vibration in the conductor and will obstruct the movement of the charges which build up electric current, hence increasing the resistance of conductivity.
Yes.
-- 'Acceleration' does NOT mean 'speeding up'.
It means ANY change in the speed OR direction of motion ...
speeding up, slowing down, or turning.
-- If an object is NOT moving in straight line at constant speed,
then its motion is accelerated.
-- In circular motion, or even just going around a curve,
the object is accelerating, because its direction is constantly
changing, even if its speed is constant.
A) We want to find the work function of the potassium. Apply this equation:
E = 1243/λ - Φ
E = energy of photoelectron, λ = incoming light wavelength, Φ = potassium work function
Given values:
E = 2.93eV, λ = 240nm
Plug in and solve for Φ:
2.93 = 1243/240 - Φ
Φ = 2.25eV
B) We want to find the threshold wavelength, i.e. find the wavelength such that the energy E of the photoelectrons is 0eV. Plug in E = 0eV and Φ = 2.25eV and solve for the threshold wavelength λ:
E = 1243/λ - Φ
0 = 1243/λ - Φ
0 = 1243/λ - 2.25
λ = 552nm
C) We want to find the frequency associated with the threshold wavelength. Apply this equation:
c = fλ
c = speed of light in a vacuum, f = frequency, λ = wavelength
Given values:
c = 3×10⁸m/s, λ = 5.52×10⁻⁷m
Plug in and solve for f:
3×10⁸ = f(5.52×10⁻⁷)
f = 5.43×10¹⁴Hz