You visited us 1 times! Enjoying our articles? Unlock Full Access!

Byju's Answer

Standard XII

Physics

I vs V - Varying Frequency

In fig, elect...

Question

In fig, electromagnetic radiations of wavelength $200 n m$ are incident on a metallic plate A. The photoelectrons are accelerated by a potential difference of $10 V$ .These electrons strike another metal plate B from which electromagnetic radiations are emitted. The minimum wavelength of emitted photons is $100 n m$ . If the work function of metal A is found to be $(x \times 10^{- 1}) e V$ , then find the value of $x$ . (Given $h c = 1240 e V n m)$

Open in App

Solution

Let us first find the initial energy of the electron just after the light strikes the plate :
$E_{i}$ = $\frac{h C}{λ}$ - $ϕ$ = $\frac{1240}{200} - ϕ$ = $6.2 - ϕ$
After this it gains energy from the battery. Now the total energy becomes :
$E_{f}$ = $E_{i}$ + $10$ = $16.2 - ϕ$
This energy is released as light from the other plate .
$\frac{h C}{λ_{2}}$ = $16.2 - ϕ$
$\frac{1240}{100}$ = $16.2 - ϕ$
$ϕ = 16.2 - 12.4 = 3.8 = 38 \times 10^{- 1}$
Hence $x = 38$

Suggest Corrections

Similar questions

Q. In the figure shown electromagnetic radiations of wavelength

200 nm

are incident on the metallic plate

A

. The photo electrons are accelerated by a potential difference

10 V

. These electrons strike another metal plate

B

from which electromagnetic radiations are emitted. The minimum wavelength of the emitted photons is

100 nm

. The work function of the metal

A

x eV

, then the value of

x + 2.2

is (use

h c = 12400 eV \circ A

)

Q. When electromagnetic radiation of wavelength

500 \circ A

is incident on a metal sheet that has a work function of 15.6 eV, find the maximum kinetic energy of the photoelectrons emitted.
Take

h = 6.6 \times 10^{- 34} J s

Q. When electromagnetic radiation of wavelength

396 \circ A

is incident on a metal sheet that has a work function of 15.6 eV, find the maximum kinetic energy of the photoelectrons emitted.
Take

h = 6.6 \times 10^{- 34} J s

Q. In a photoelectric setup, the radiations from the Balmer series of hydrogen atom are incident on a metal surface of work function

2 e V

. The wavelength of incident radiations lies between

450 n m

700 n m

. Find the maximum kinetic energy of photoelectron emitted. (Given

h c / e = 1241 e V - n m)

When an electromagnetic radiation of wavelength $310 n m$ falls on the surface of sodium metal, electrons are emitted with $K . E_{m a x} = 1.5 e V$ . Determine the work function $W_{o}$ of metal.

Join BYJU'S Learning Program