Question 7: Dual Nature of Matter and Radiation

Question

Lights of two different frequencies whose photons have energies 1.5 eV and 2.5 eV respectively illuminate a metallic surface whose work function is 0.5 eV successively. Ratio of maximum speeds of emitted electrons will be

Accepted Answer

Kinetic energy in photoelectric effect can be given as
KE = W $$-$$ W
0
[W $$	o$$ incident energy, W
0
$$	o$$ work function]
Given, (KE)
1
= 1.5 $$-$$ 0.5 = 1 eV
(KE)
2
= 2.5 $$-$$ 0.5 = 2.0 eV
$$\because$$ $${{{{(KE)}_1}} \over {{{(KE)}_2}}} = {1 \over {2}}$$
$$ \Rightarrow {{{1 \over 2}mv_1^2} \over {{1 \over 2}mv_2^2}} = {1 \over 2} \Rightarrow {{{v_1}} \over {{v_2}}} = \sqrt {{1 \over 2}} $$
$$	herefore$$ $${v_1}:{v_2} = 1 :\sqrt 2 $$
So, the ratio of maximum speeds of emitted electrons is $$1 :\sqrt 2 $$.

Answer

3 : 2

Answer

2 : 3

Answer

$$\sqrt3$$ : $$\sqrt2$$

Answer

$$1 :\sqrt 2 $$

Dual Nature of Matter and Radiation

Lights of two different frequencies whose photons have energies 1.5 eV and 2.5 eV respectively illuminate a metallic surface whose work function is 0.5 eV successively. Ratio of maximum speeds of emitted electrons will be

Choose the correct answer: