Download App

Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

Maharashtra BoardEnglish MediumSTD 12 SciencePhysicsDual Nature of Radiation and Matter1 Mark
MCQ
When light of wavelength $\lambda$ is incident on photosensitive surface, the stopping potential is $V$. When light of wavelength $3 \lambda$ is incident on same surface, the stopping potential is $\frac{V}{6}$. Threshold wavelength for the surface is
  • A
    $2 \lambda$
  • B
    $3 \lambda$
  • C
    $4 \lambda$
  • ✓
    $5 \lambda$
✓

Answer

Correct option: D.
$5 \lambda$
(d) : Einstein's photoelectric equation,
$
\begin{aligned}
& e V_0=\frac{h c}{\lambda}-\frac{h c}{\lambda_0} \\
& \therefore \quad e V=\frac{h c}{\lambda}-\frac{h c}{\lambda_0} \\
& \frac{e V}{6}=\frac{h c}{3 \lambda}-\frac{h c}{\lambda_0}
. . . . . . . (ii)\end{aligned}
$. . . . . . (i)
From eqns. (i) and (ii),
$
\begin{aligned}
& \frac{h c}{6 \lambda}-\frac{h c}{6 \lambda_0}=\frac{h c}{3 \lambda}-\frac{h c}{\lambda_0} \\
& \Rightarrow \frac{h c}{3 \lambda}-\frac{h c}{6 \lambda}=\frac{h c}{\lambda_0}-\frac{h c}{6 \lambda_0} \Rightarrow \frac{h c}{6 \lambda}=\frac{5 h c}{6 \lambda_0} \text { or } \lambda_0=5 \lambda
\end{aligned}
$

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 Dual Nature of Radiation and Matter→Dual Nature of Radiation and Matter — all question types→Physics STD 12 Science question papers→Maharashtra Board STD 12 Science question papers→Maharashtra Board question paper generator→

Similar questions

If the frequency of incident light falling on a photosensitive material is doubled, then the kinetic energy of the emitted photoelectron will be $........$
→
In the following circuit diagram, an infinite series of resistances is shown. Equivalent resistance between points A and B is

Image

→
A mass is suspended from a vertical spring which is executing. $\text{S.H.M.}$ of frequency $5\ Hz$. The spring is unstretched at the highest point of oscillation. Maximum speed of the mass is $[$acceleration due to gravity $g=10\ m / s ^2 ]$
→
A body is said to be opaque to the radiation if ( $a, r$ and $t$ are coefficient of absorption, reflection and transmission respectively)
→
In a gravity free space, the liquid in a capillary tube will rise to
→
In biprism experiment, the distance of 20th bright band from the central bright band is 1.2 cm. Without changing the experimental set-up, the distance of 30 bright band from the central bright band will be ______.
→
The electrons are emitted in the photoelectric effect from a metal surface.
→
When open pipe is closed from one end then third overtone of closed pipe is higher in frequency by $150 Hz$ than second overtone of open pipe. The fundamental frequency of open end pipe will be
→
Consider following cases:
(P) A planet revolving in an elliptical orbit.
(Q) A planet revolving in a circular orbit.
Principle of conservation of angular momentum comes in force in which of these?
→
If flux is given as $\phi=3 t^2+4 t+8$. Then find the induced emf at $t=2 s$
→