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katen-ka-za [31]
3 years ago
6

I NEED HELP ASAP

Physics
1 answer:
34kurt3 years ago
4 0
I think it’s gonna be b.
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If light of wavelength 700 nm strikes such a photocathode, what will be the maximum kinetic energy, in eV , of the emitted elect
Oksana_A [137]

If the light of wavelength 700 nm strikes such a photocathode the maximum kinetic energy, in eV, of the emitted electrons is 0.558 eV.

so - $KE_{max} = hc/lembda}  work

threshold when KE = 0

hc/lambda = work = 1240/900=1.38 eV

b) Kemax = hc/lambda - work = 1240/640 -1.38=0.558 eV

What is photocathode?

  • A photocathode electrolyte interface can be used in a photoelectrolysis cell as the primary light-harvesting junction (in conjunction with an appropriate electrochemical anode) or as an optically complementary photoactive half-cell in a tandem photoelectrode photoelectrolysis cell (Hamnett, 1982; Kocha et al, 1994).
  • In the case of the former, the electrode should ideally harvest photon energy across the majority of the solar spectrum in order to achieve the highest energy conversion efficiency possible.
  • In the latter case, however, the photocathode may only be active in a specific band of the solar spectrum in order to generate a cathodic photocurrent sufficient to match the current generated in the photoanodic half-cell.

To learn more about Photocathode from the given link:

brainly.com/question/9861585

#SPJ4

3 0
2 years ago
20.0 Ω resistor and a 2.50 μF capacitor are connected in parallel with signal generator. The signal generator produces a sinusoi
Free_Kalibri [48]

Answer:

0.15A

Explanation:

The parameters given are;

R=20.0 Ω

C= 2.50 μF

V= 3.00 V

f= 2.48×10^-3 Hz

Xc= 1/2πFc

Xc= 1/2×3.142 × 2.48×10^-3 × 2.5 ×10^-6

Xc= 25666824.1

Z= 1/√(1/R)^2 +(1/Xc)^2

Z= 1/√[(1/20)^2 +(1/25666824.1)^2]

Z= 1/√(2.5×10^-3) + (1.5×10^-15)

Z= 20 Ω

But

V=IZ

Where;

V= voltage

I= current

Z= impedance

I= V/Z

I= 3.00/20

I= 0.15A

6 0
3 years ago
A person walks from her home at position O to position F by taking a path that is comprised of three displacement vectors travel
lidiya [134]

Answer:

Explanation:

A = 155 m at 25° North of west

B = 92 m due north

C = 64.7 m at an angle 50° East of north

Write the displacements in the vector form

\overrightarrow{A} = 155\left ( Cos25\widehat{i}-Sin25\widehat{j} \right )

\overrightarrow{A}=140.5\widehat{i}-65.5\widehat{j}

\overrightarrow{B}=92\widehat{j}

\overrightarrow{C} = 64.7\left ( Cos50\widehat{i}+Sin50\widehat{j} \right )

\overrightarrow{C} = 41.6\widehat{i}+49.6\widehat{j}

(a)

\overrightarrow{A}.\overrightarrow{C}=\left ( 140.5\widehat{i}-65.5\widehat{j} \right ).\left ( 41.6\widehat{i}+49.5\widehat{j} \right )

\overrightarrow{A}.\overrightarrow{C} = 2602.55

(b)

\overrightarrow{A}\times \overrightarrow{C}=\left ( 140.5\widehat{i}-65.5\widehat{j} \right )\times \left ( 41.6\widehat{i}+49.5\widehat{j} \right )

\overrightarrow{A}\times \overrightarrow{C}=9679.55 \widehat{k}

4 0
3 years ago
The owners want the speed at the bottom of the first hill doubled. How much higher must the first hill be built?
Sonja [21]
Neglecting friction and air resistance, the first hill must be built 4 times higher than it is now.
3 0
4 years ago
A 620 kg car is traveling at 24 m/s on horizontal ground when it starts up a 30 m high hill. The engine can produce up to 144,00
sweet-ann [11.9K]

Answer:

The kinetic energy of the car at the top of the hill is 140280 Joules.

Explanation:

Mass of the car, m = 620 kg

Speed of the car, v = 24 m/s

Height of the hill, h = 30 m

The engine can produce up to 144,000 J of work during that time, W = 144,000 J

We need to find the kinetic energy of the car at the top of the hill. It can be calculated using conservation of mechanical energy as :

(mgh+K)-\dfrac{1}{2}mv^2=144000

(620\times 9.8\times 30+K)-\dfrac{1}{2}\times 620\times (24)^2=144000

620\times9.8\times30+K=322560

K=140280\ J

So, the kinetic energy of the car at the top of the hill is 140280 Joules. Hence, this is the required solution.

7 0
4 years ago
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