JEE Main 2002 — Optics

Which of the following is used in optical fibres ?

Wavelength of light used in an optical instrument are $\lambda_1=4000 Å$ and $\lambda_2=5000 Å$, then ratio of their respective resolving powers (corresponding to $\lambda_1$ and $\lambda_2$ ) is

If two mirrors are kept at $60^{\circ}$ to each other, then the number of images formed by them is