Question

In the Young’s Experiment regarding interference, one of the slits is covered by a thin film that absorbs 50% of the incident light. Then

• A. the bandwidth in the interference pattern increases
• B. the contrast between the bright and dark bands increases
• C. the ratio of brightness of a bright band to that of a dark band is about 25:1
• D. there will be a shift in the position of the central bright band

Answer 1

The correct option is D there will be a shift in the position of the central bright band

Bandwidth is independent of intensity contrast is less when amplitudes are different. Ratio of amplitudes $1:\sqrt{2}$.

Intensity ratio is $\frac{(1.4+1{)}^2}{(1.4-1{)}^2}=36$.
Central fringe will shift due to additional optical path.