The ratio of the speed of light in a medium to the speed of light in a vacuum
2 answers:
You might be interested in
Answer:
Explanation:
Energy of signal being radiated per second on all sides = 71 x 10³ J .
At a distance of 220 m it is spread over an area of 4 π x (220)² because it is spreading uniformly on all sides.
So energy crossing per unit area
=
= 11.67 x 10⁻² Wm⁻²s⁻¹.
This is the intensity of the signal.
At 2200 m this intensity will further reduce by 100 times
So there it becomes equal to
11.67 x 10⁻⁴ Wm⁻² s⁻¹.
Given parameters:
Mass of the body = 200g
Force on the body = 10N
Unknown parameters:
Acceleration produced by the force = ?
To solve this problem we must first define force in terms of mass and acceleration. This is possible due to the Newton's first law of motion.
Force = mass x acceleration
Here the unknown is acceleration and we can easily solve for it.
But we must take the mass to kilogram in order for it to cancel out.
1000g = 1 kg
200g = x kg = = 0.2kg
Now input the parameters and solve;
10 = 0.2 x acceleration
Acceleration = = 50m/s²
The acceleration produced by the body is 50m/s²
Answer:
The speed of the electron is 1.371 x 10⁶ m/s.
Explanation:
Given;
wavelength of the ultraviolet light beam, λ = 130 nm = 130 x 10⁻⁹ m
the work function of the molybdenum surface, W₀ = 4.2 eV = 6.728 x 10⁻¹⁹ J
The energy of the incident light is given by;
E = hf
where;
h is Planck's constant = 6.626 x 10⁻³⁴ J/s
f = c / λ
Photo electric effect equation is given by;
E = W₀ + K.E
Where;
K.E is the kinetic energy of the emitted electron
K.E = E - W₀
K.E = 15.291 x 10⁻¹⁹ J - 6.728 x 10⁻¹⁹ J
K.E = 8.563 x 10⁻¹⁹ J
Kinetic energy of the emitted electron is given by;
K.E = ¹/₂mv²
where;
m is mass of the electron = 9.11 x 10⁻³¹ kg
v is the speed of the electron
Therefore, the speed of the electron is 1.371 x 10⁶ m/s.