The GATE Grind

GATE 2025 PH – Question 41

Electronics · basics of digital logic circuits, combinational and sequential circuits, flip- flops, timers, counters, registers, A/D and D/A conversion. · 2 marks · Multiple choice

An α particle is scattered from an Au target at rest as shown in the figure. D1 and D2 are the detectors to detect the scattered α particle at an angle θ and along the beam direction, respectively, as shown. The signals from D1 and D2 are converted to logic signals and fed to logic gates. When a particle is detected, the signal is 1 and is 0 otherwise. Which one of the following circuits detects the particle scattered at the angle θ only?

Scattering detectors D1 and D2 and four logic circuits.
  1. Option A in the figure
  2. Option B in the figure
  3. Option C in the figure
  4. Option D in the figure

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Show answer and explanation

Correct answer: (A) Option A in the figure

Explanation

Accepting a scattered particle but rejecting a beam-direction detection requires $D_1\land\neg D_2$. Circuit A implements this veto.