A photoelectric cell is an electronic device which is used to convert light energy into electric energy.The operation of this device is based on photoelectric effect.
Light of suitable frequency i.e greater or equal to threshold frequency will fall on the cathode maintained at negative potential.The electron emission will take place and these electrons are drifted towards the anode which is at positive potential.
Here,only those radiations will be capable of emitting electrons irrespective of surface barrier of metals whose energy is greater than the work function.
We know that the radiation having long wavelength has least energy as energy and wavelength are inversely proportional to each other.
Here h is the Planck's constant,c is the velocity of light.
Here we have been given red light and blue light.
In the visible spectrum of radiation, the red light has longer wavelength than all other colors of light.Hence blue light has more energy as it's wavelength is less as compared to red light.
Hence, the blue light will activate the most and red the least.
Answer:
a) V = 1.866 10² V
, b) V = 3.424 10⁵ V
, c) v = 8.1 10⁶ m / s
Explanation:
a) the potential difference is requested to accelerate the electrons up to 2.7% of the speed of light
v = 0.027 c
v = 0.027 3 10⁸
v = 8.1 10⁶ m / s
for this part we can use the conservation of mechanical energy
starting point. When electrons are at rest
Em₀ = U = q V
final point. Electrons with maximum speed
Em_f = K = ½ m v2
Em₀ = Em_{f}
e V = ½ m v²
V = ½ m v² / e
let's calculate
V = ½ 9.1 10⁻³¹ (8.1 10⁶)² / 1.6 10⁻¹⁹
V = 1.866 10² V
V = 1866 V
b) if this acceleration protons is the mass of the proton is m_{p} = 1.67 10-27
V = ½ 1.67 10⁻²⁷ (8.1 10⁶)² / 1.6 10⁻¹⁹
V = 3.424 10⁵ V
V = 342402 V
c)
this potential difference should give the protons the same speed as the electrons
v = 8.1 10⁶ m / s
Answer:
a) E = ρ / e0
b) E = ρ*a / (e0 * r)
c) E = 0
Explanation:
Because of the geometry, the electric field lines will all have a radial direction.
Using Gauss law
Using a Gaussian surface that is cylinder concentric to the cable, the side walls will have a flux of zero, because the electric field lines will be perpendicular. The round wall of the cylinder will have the electric field lines normal to it.
We can make this cylinder of different radii to evaluate the electric field at different points.
Then:
A = 2*π*r (area of cylinder per unit of length)
Q/e0 = 2*π*r*E
E = Q / (2*π*e0*r)
Where Q is the charge contained inside the cylinder.
Inside the cable core:
There is a uniform charge density ρ
Q(r) = ρ * 2*π*r
Then
E = ρ * 2*π*r / (2*π*e0*r)
E = ρ / e0 (electric field is constant inside the charged cylinder.
Between ther inner cilinder and the tube:
Q = ρ * 2*π*a
E = ρ * 2*π*a / (2*π*e0*r)
E = ρ*a / (e0 * r)
Outside the tube, the charges of the core cancel each other.
E=0
Answer: The spring of the spring is 25 N/m.
Explanation:
Mass of the body = 25 g= 0.025 kg (1 kg = 1000 g)
Oscillation is 4 sec = 20
Oscillation in 1 sec =
Frequency of the vibration of the spring = 
Force constant can be calculated bu using the relation between the frequency and, mass and spring constant 'k'
The spring of the spring is 25 N/m.
