Question

For photoelectric emission, tungsten requires light of 2300$\mathring{A}$. If light of 1800 $\mathring{A}$ wavelength is incident, then emission :

• A. Takes place
• B. Doesn't take place
• C. May or may not lake place
• D. Depends on frequency

Answer 1

The correct option is A Takes place

By Einstein's photoelectric equation, the maximum kinetic energy of the photoelectrons is $K{E}_{max}=hf-h{f}_0$

where $h=$ Plank's constant, $f=$ frequency of incident light and $f_0=$ threshold frequency for the metal.

As kinetic energy is positive, so we must have $f>f_0$ for the occurrence of photoelectric effect.

Here, $f=2300A^o$ and $f_0=1800A^o$

As $f>f_0$, photo emission will take place.