. State the principle of moving coil galvanometer
is 0.02 cm is placed immediately in front of a lens of focal length 60 cm. The aperture is illuminated normally by a
parallel beam of wavelength 5 × 10^-5 cm. The distance of the first dark band of the diffraction pattern from the centre of the screen is:
A: 0.15 cm
B: 0.10 cm
C: 0.25 cm
D: 0.20 cm
Hence, the correct option is (A) i.e. 0.15cm.