Light of wavelength ',$$\lambda$$' is incident on a slit of width '$$\mathrm{d}$$'. The resulting diffraction pattern is observed on a screen at a distance '$$D$$'. The linear width of the principal maximum is then equal to the width of the slit if $$D$$ equals

Two S.H.Ms. are represented by equations $$\mathrm{y}_1=0.1 \sin \left(100 \pi \mathrm{t}+\frac{\pi}{3}\right)$$ and $$\mathrm{y}_2=0.1 \cos (100 \pi \mathrm{t})$$ The phase difference between the speeds of the two particles is

A film of soap solution is formed between two straight parallel wires of length $$10 \mathrm{~cm}$$ each separated by $$0.5 \mathrm{~cm}$$. If their separation is increased by $$1 \mathrm{~mm}$$ while still maintaining their parallelism. How much work will have to be done?

(surface tension of solution $$=65 \times 10^{-2} \mathrm{~N} / \mathrm{m}$$ )

An ideal gas in a container of volume 500 c.c. is at a pressure of $$2 \times 10^{+5} \mathrm{~N} / \mathrm{m}^2$$. The average kinetic energy of each molecule is $$6 \times 10^{-21} \mathrm{~J}$$. The number of gas molecules in the container is