In your own words who discovered gadolinium

Who Discovered Gadolinium Gadolinium was only discovered in 1880 by a Swiss chemist called Jean Charles Galissard de Marignac.

Explanation:

When analyzing samples of two minerals which contain small amounts of gadolinium, didymium and gadolinite, he discovered spectroscopic lines that were unrecognisable. Every single element has distinctive spectroscopic lines so he knew he had discovered a new element, and called it gadolinium after Finnish chemist Johan Gadolin.

d

explanation:

v=uf/(u-f)

= 5.10/(5-10) convex lens has positive focal length

=50/-5

=-10 cm (formed at other side)

mistakes are ok