Physics Circle home Student Login

Home›Chapters›Dual Nature of Radiation and Matter PYQs›Photoelectric Experiment: Intensity, Stopping Potential & Graphs›Question 74

NEET 2007 (AIPMT) · Photoelectric Experiment: Intensity, Stopping Potential & Graphs

Photoelectric Experiment: Intensity, Stopping Potential & Graphs question from NEET 2007 (AIPMT)

Q74NEET 2007 · AIPMTMedium

Photoelectric Experiment: Intensity, Stopping Potential & Graphs

A 5 watt source emits monochromatic light of wavelength 5000 A˚\text{\AA}. When placed 0.5 m away, it liberates photoelectrons from a photosensitive metallic surface. When the source is moved to a distance of 1.0 m, the number of photoelectrons liberated will be reduced by a factor of

Show answer and solution

Answer: (d)

  1. Intensity of a point source ∝1r2\propto \frac{1}{r^2}; number of photoelectrons ∝\propto intensity.
  2. r:0.5→1.0r: 0.5 \to 1.0 m (doubled) ⇒\Rightarrow intensity becomes 14\frac{1}{4}.
  3. So the answer is (d) 4.
Report a mistake

More questions on Photoelectric Experiment: Intensity, Stopping Potential & Graphs