$A$ Young's double slit experiment uses a monochromatic source. The shape of the interference fringes formed on a screen is

In a Young's double slit experiment,$12$ fringes are observed to be formed in a certain segment of the screen when light of wavelength $600 \ nm$ is used. If the wavelength of light is changed to $400 \ nm$,the number of fringes observed in the same segment of the screen is:

In Young's double-slit experiment,the intensity at a point on the screen where the path difference is $\lambda/6$ is $I$. If the intensity of the central bright fringe is $I_0$,then $I/I_0$ is:

In Young's double-slit experiment,when light of wavelength $\lambda_1 = 5898 \ \mathring{A}$ is used,$92$ fringes are observed in a certain region. If light of wavelength $\lambda_2 = 5461 \ \mathring{A}$ is used instead,how many fringes will be observed in the same region?

In Young's double-slit experiment,if a metal plate of thickness $t$ is placed in the path of one of the rays,then:

In Young's double-slit experiment,using light of wavelength $\lambda = 5890 \ \mathring{A}$,the angular width of the fringe is $0.20^\circ$. To increase the angular width by $10\%$,the wavelength must be increased by .......... $\mathring{A}$.