Light of two different frequencies whose photons have energies 1eV

⇦

⇨

Light of two different frequencies whose photons have energies 1 eV and 2.5 eV respectively illuminate a metallic surface whose work function is 0.5 eV successively. Ratio of maximum speed of emitted electrons will be

Options

(a) 1 : 4
(b) 1 : 2
(c) 1 : 1
(d) 1 : 5

Correct Answer:

1 : 2

Explanation:

The maximum kinetic energy of emitted electrons is given by
K.E = WorkFunction(₀) – WorkFunction(₁)
K.E₁ = 1 eV – 0.5 eV = 0.5 eV
K.E₂ = 2.5 eV – 0.5 eV = 2.0 eV
K.E₁ / K.E₂ = 0.5 eV / 2 eV = 1/4

KE = mv² /2
v₁ / v₂ = √1/4 = 1/2

Related Questions:

1. A satellite A of mass m is at a distance r from the centre of earth. Another satellite
2. A particle is kept at rest at the top of a sphere of diameter 42m.When disturbed slightly
3. Fusion reaction takes place at high temperature because
4. A scooter is going round a circular road of radius 100 m at a speed of 10m/s
5. A body initially at rest is moving with uniform acceleration a m/s²

Topics: Dual Nature of Matter and Radiation (150)
Subject: Physics (2479)

---

Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score

18000+ students are using NEETLab to improve their score. What about you?

Solve Previous Year MCQs, Mock Tests, Topicwise Practice Tests, Identify Weak Topics, Formula Flash cards and much more is available in NEETLab Android App to improve your NEET score.

---

Share this page with your friends