When a metal surface is illuminated by light of wavelength , the … - Vidyadip

MCQ

When a metal surface is illuminated by light of wavelength $\lambda$, the stopping potential is $8 \mathrm{~V}$. When the same surface is illuminated by light of wavelength $3 \lambda$, stopping potential is $2 \mathrm{~V}$. The threshold wavelength for this surface is :

A
$5 \lambda$
B
$3 \lambda$
✓
$9 \lambda$
D
$4.5 \lambda$

✓

Answer

Correct option: C.

$9 \lambda$

c
$\mathrm{E}=\phi+\mathrm{K}_{\max }$

$\phi=\frac{\mathrm{hc}}{\lambda_0}$

$\mathrm{~K}_{\max }=\mathrm{eV}_0$

$8 \mathrm{e}=\frac{\mathrm{hc}}{\lambda}-\frac{\mathrm{hc}}{\lambda_0} \ldots . . \text { (i) }$

$2 \mathrm{e}=\frac{\mathrm{hc}}{3 \lambda}-\frac{\mathrm{hc}}{\lambda_0} \ldots . . . \text { (ii) }$

$\text { on solving (i) & (ii) }$

$\lambda_0=9 \lambda$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "M.C.Q (1 Marks)" from 11. Dual nature of radiation and matter→11. Dual nature of radiation and matter — all question types→Physics STD 12 Science question papers→CBSE Board STD 12 Science question papers→CBSE Board question paper generator→

Similar questions

A wire of radius $r$ has resistance $R$. If it is stretched to a radius of $\frac{{3r}}{4}$, its resistance becomes

In a series $L-C-R$ circuit the frequency of a $10\,volt$ $a.c.$ voltage source is adjusted in such a fashion that the reactance of the inductor measures $15\,\Omega $ and that of the capacitor $11\,\Omega $. If $R = 3\,\Omega $, the potential difference across the series combination of $L$ and $C$ will be.....$V$

The resistance of a wire is $R$. If the length of the wire is doubled by stretching, then the new resistance will be

In a photoelectron experiment, the stopping potential from the photoelectrons is $2V$ for the incident of wavelength $400\ nm$. If the incident light is changed to $300\ nm$, the cut$-$off potential is:

A steady current is passing through a linear conductor of non uniform cross$-$section. The net quantity of charge crossing any cross section per second is:

The value of the resistance $R$ in figure is adjusted such that power dissipated in the $2\,\Omega $ resistor is maximum. Then the power dissipated in the $2\,\Omega $ will be ................ $W$

The curve between current $(i)$ and potential difference $(V)$ for a photo cell will be

In two separate set - ups of the Young's double slit experiment, fringes of equal width are observed when lights of wavelengths in the ratio 1 : 2 are used. If the ratio of the slit separation in the two cases is 2 : 1, the ratio of the distances between the plane of the slits and the screen in the two set - ups is

In a parallel plate capacitor set up, the plate area of capacitor is $2 \,m ^{2}$ and the plates are separated by $1\, m$. If the space between the plates are filled with a dielectric material of thickness $0.5\, m$ and area $2\, m ^{2}$ (see $fig.$) the capacitance of the set-up will be $.........\, \varepsilon_{0}$

(Dielectric constant of the material $=3.2$ ) and (Round off to the Nearest Integer)

Which one of the following statements is correct