Conversion : J ➝ Cal
[tex]\bigstar\:\boxed{\bf{\purple{4.2\:Joule=1\:Cal}}}[/tex]
[tex]:\implies\sf\:3.5\times 10^6\:J[/tex]
[tex]:\implies\sf\:3.5\times 10^6\:J\times \dfrac{1\:Cal}{4.2\:J}[/tex]
[tex]:\implies\sf\:0.833\times 10^6\:Cal[/tex]
[tex]:\implies\bf\:8.33\times 10^5\:Cal[/tex]