A. a beam of monochromatic coherent light
B. a beam of monochromatic incoherent light
C. highly penetrating X-rays
D. a beam of a fast moving neutron rays
Free MCQs for FPSC, NTS, PPSC, PMS, CSS & All Pakistan Exams 2026
A. a beam of monochromatic coherent light
B. a beam of monochromatic incoherent light
C. highly penetrating X-rays
D. a beam of a fast moving neutron rays