Asked by  | 14th Jun, 2009, 01:08: PM

Expert Answer:

1. (1) relative density : hygrometer

           Note- Hygrometer is used to measure the relative humidity of the sir.

2.  (2)radioactivitywas discovered by Madam Curie

        Note -  Radioactivity was discovered by Antonie Henri Becquerel in 1986.

Answered by  | 14th Jun, 2009, 02:28: PM

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