1- An aqueous solution Y contains both barium ions and silver ions.
In separate experiments, dilute sulfuric acid and dilute hydrochloric acid are added to solution Y.
Which of these acids causes a precipitate to form in solution Y?
dilute
sulfuric acid
dilute
hydrochloric acid
2-

black Black Black Black Black Black Black Black

the transfer of heat by electromagnetic radiation is called thermal radiation . it is usually carried out by electromagnetic waves in an energy range just below the visible spectrum, which is the infrared range.

so the answer would be radiation.

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