JEE Main 2019PhysicsDual Nature of MatterMediumMCQ

JEE Main 2019 — Dual Nature of Matter Question with Solution

JEE Main 2019 (09 Jan Shift 2)

Question

The magnetic field associated with a light wave is given, at the origin, by B=B0 sin⁡3.14×107ct+sin⁡6.28×107ct. If this light falls on a silver plate having a work function of 4.7eV, what will be the maximum kinetic energy of the photoelectrons?

(c=3×108 m s−1,h=6.6×10−34 J s)

Choose an option

Show full solutionCorrect option: B
Correct answer
B7.72 eV

Step-by-step explanation

B=B0sin⁡3.14×107ct+sin⁡6.28×107ct

Maximum KE will associate with the maximum frequency

fmax⁡ =6.28×107c2π=107×3×108 Hz           =3×1015 Hz

KEmax=hfmax-ϕ

=6.63×10-34×3×10151.6×10-19-4.7 eV

=7.72 eV

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About this question

This is a previous-year question from JEE Main 2019, covering the Dual Nature of Matter chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.