MCQ
Work function of a metal is 2.51 eV. Its threshold frequency is
  • A
    $5.9 \times 10^{14}$ cycle$/\mathrm{sec}$
  • B
    $6.5 \times 10^{14}$ cycle$/\mathrm{sec}$
  • C
    $9.4 \times 10^{14}$ cycle$/\mathrm{sec}$
  • $6.08 \times 10^{14}$ cycle$/\mathrm{sec}$

Answer

Correct option: D.
$6.08 \times 10^{14}$ cycle$/\mathrm{sec}$
(d) $6.08 \times 10^{14}$ cycle$/\mathrm{sec}$

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

Similar questions

The angle of dip is the angle
The sensitivity of a Galvenometer of resistance $171\,\Omega $ becomes $20\,times$ when we used shunt of $x \,\Omega .$ Find $x$ ................. $\Omega$
Two identical p-ri junctions may be connected in series with a battery in three ways (figure). The potential difference across the two p-n. junctions are equal in:
$(1):$ The dielectric medium between the plates of a parallel plate capacitor lowers the potential difference between the plates without a battery.
$(2):$ The maximum electric field that a dielectric can withstand without causing it to break down is dielectric strength.
If yellow light emitted by sodium lamp in Young's double slit experiment is replaced by monochromatic blue light of the same intensity
An optical device is constructed by fixing three identical convex lenses of focal lengths $10 \,cm$ each inside a hollow tube at equal spacing of $30 \,cm$ each. One end of the device is placed $10 cm$ away from a point source. ........... $cm$ the image shift when the device is moved away from the source by another $10 \,cm$ ?
If reading of voltmeter $V$ shown in the figure at resonance is $200 \,V$, then the quality factor of the circuit is
What conclusion is drawn regarding the magnetic field at a point if a compass needle at that point rests in any direction?
Two radioactive substances $X$ and $Y$ originally have $N _{1}$ and $N _{2}$ nuclei respectively. Half life of $X$ is half of the half life of $Y$. After three half lives of $Y$, number of nuclei of both are equal. The ratio $\frac{ N _{1}}{ N _{2}}$ will be equal to
A star moves away from earth at speed $0.8\, c$ while emitting light of frequency $6 \times 10^{14} \,Hz$. What frequency will be observed on the earth ? 
($c =$ speed of light)