Question

the threshold photoelectric effects in Tungsten is produced by light of a wavelength 260 nm give the energy of a photon of this light in Joules. ​

Answer 1

Answer:

Energy of light is $7.62\times 10^{-17} \ Joules$

Explanation:

Given:

Wavelength $(\lambda)=260 \ nm=2.60 \times 10^{-7} m$

Also we know the speed of light $(c) =3 \times 10^8 \ m/s$

To calculate frequency of light $(v)$, divide speed of light$(c)$ by Wavelength$(\lambda)$

$v= \frac{3 \times 10^8}{2.60\times 10^{-7}}= 1.15\times 10^{15} \ per \ second$

Hence frequency is $1.15\times 10^{15} \ per \ second$

Now, To calculate energy (E), we need to multiply planks's constant $(h)$ with the frequency of light  $(v)$.

Also Plank's Constant $(h)$ = $6.626\times 10^{-34}\ J \ s$

$E = h \times. f = 6.626\times 10^{-34}\ J \ s \times 1.15 \times 10^{15}\ s^{-1} = 7.62 \times 10^{-19} \ J$

Hence Energy of light is $7.62\times 10^{-19} \ Joules$