If a metal with a threhold frequency of 1.1 x 10^15 Hz is illuminated by light with a wavelength of 170 nm, then the maximum kinetic energy of the emitted photoelectron will be?
this is my solution:
h= 6.63 x 10^ -34 J.s
c = 3 x 10^8 m/s
Wavelength= 1.7 x 10^-7 m
Threshold frequency = 1.1 x 10^15 Hz
E max = hc/wavelength + Threshold frequency
E max = 6.63 X 10^-34 (3 X 10^8)/ 1.7 X 10^-7 + 1.1 X 10^15
The answer should be 4.4 x 10^ -19 J
but i keep on getting 1.1 x 10^ 15
Plz can u anyone explain me what am I doing wrong here??
Thank u in advance =)
even if i try
hc/wavelength - Threshold frequency i still don't get the right answer
Your units are messed up.
On the right, energy + frequency?
convert the threshhold frequency to energy or...
Emax=h(c/wavelength - frequency) should do the work.
To calculate the maximum kinetic energy of the emitted photoelectron, we need to use the Einstein's photoelectric equation, which relates the energy of a photon to its frequency and the work function of the metal.
The equation is given by:
E = hf - Φ
Where:
E is the energy of the photon (maximum kinetic energy of the photoelectron)
h is Planck's constant (6.63 x 10^-34 J.s)
f is the frequency of the incident light
Φ is the work function (also called the threshold energy)
In this case, the threshold frequency is provided, which is 1.1 x 10^15 Hz. We need to convert the wavelength of the incident light to frequency using the formula:
c = λf
Where:
c is the speed of light (3 x 10^8 m/s)
λ is the wavelength of the light
We are given the wavelength (170 nm) in nanometers, so we need to convert it to meters:
1 nm = 1 x 10^-9 m
Thus, the wavelength in meters is:
λ = 170 x 10^-9 m = 1.7 x 10^-7 m
Now, we can calculate the frequency of the incident light:
c = λf
f = c / λ
f = (3 x 10^8 m/s) / (1.7 x 10^-7 m)
f ≈ 1.76 x 10^15 Hz
Now, we can substitute the values into the photoelectric equation:
E = hf - Φ
E = (6.63 x 10^-34 J.s) × (1.76 x 10^15 Hz) - (1.1 x 10^15 Hz)
E ≈ 1.17 x 10^-18 J - 1.1 x 10^-15 J
E ≈ -1.09883 x 10^-15 J
It seems that there was an error in your calculations. The answer you mentioned (4.4 x 10^-19 J) is not correct. The correct answer is approximately -1.09883 x 10^-15 J.
Please double-check your calculations and make sure you are using the correct values and units.