Answer: a) 274.34 nm; b) 1.74 eV c) 1.74 V
Explanation: In order to solve this problem we have to consider the energy balance for the photoelectric effect on tungsten:
h*ν = Ek+W ; where h is the Planck constant, ek the kinetic energy of electrons and W the work funcion of the metal catode.
In order to calculate the cutoff wavelength we have to consider that Ek=0
in this case h*ν=W
(h*c)/λ=4.52 eV
λ= (h*c)/4.52 eV
λ= (1240 eV*nm)/(4.52 eV)=274.34 nm
From this h*ν = Ek+W; we can calculate the kinetic energy for a radiation wavelength of 198 nm
then we have
(h*c)/(λ)-W= Ek
Ek=(1240 eV*nm)/(198 nm)-4.52 eV=1.74 eV
Finally, if we want to stop these electrons we have to applied a stop potental equal to 1.74 V . At this potential the photo-current drop to zero. This potential is lower to the catode, so this acts to slow down the ejected electrons from the catode.
The sun is a clear example of objects releasing radiation in nature
Answer: Hello!
Lewis is travelling at 165 mph, which means miles per hour, this says that he does 165 miles in one hour.
We want to know how much time takes to cover 16 miles.
this can be calculated as the quotient of the distance and the velocity; this is:
if we want to write this in minutes, then:
we know that one hour has 60 minutes, then 0.096 hours has:
0.096h*60mins/1h = 5.8 minutes.
then Lewis needs 5.8 minutes in order to cover 16 miles if his speed is 156 miles per hour.
The resistance expected of the heater is 50.1 ohms.
<h3>What is resistance?</h3>
Resistance can be defined as the opposition to the flow of electric current in an electric circuit. The S.I unit of resistance is Ohms (Ω).
To calculate the resistance of the heater, we use the formula below.
<h3>Formula:</h3>
- R = V²/P............. Equation 1
Where:
- R = Resistance of the heater
- P = Power of the heater
- V = Voltage supplied to the heater
From the question,
Given:
- V = 480 V
- P = 4.6 kW = 4600 W
Substitute these values into equation 1
- R = (480²)/4600
- R = 50.1 ohms.
Hence, the resistance expected of the heater is 50.1 ohms.
Learn more about resistance here: brainly.com/question/17563681
Answer:
U = 8.30×10-⁹J
Explanation:
m1 = m2 = 5.00kg masses of the spheres
d = 15.0cm = 15×10-²m
r = 5.10cm = 5.10×10-²m
R = d + r = 15×10-² + 5.10×10-²
R = 20.10 ×10-²m = 0.201m
G = 6.67×10-¹¹Nm²/kg²
U = Gm1×m2/R = potential energybetween the spheres
U = 6.67×10-¹¹×5.00×5.00/0.201
U = 8.30×10-⁹J
