UN Fisika 2016 Paket 1 Nomor 20

Logam yang massanya 100 gram dipanaskan sampai 75 {}^\circ C kemudian dimasukkan ke dalam 500 gram air pada suhu  25 {}^\circ C. Setelah keadaan setimbang suhu campuran menjadi  50 {}^\circ C. Apabila kalor jenis air 4200 J.k{{g}^{-1}}{}^\circ {{C}^{-1}}, maka kalor jenis logam adalah …

A.    4,2\times {{10}^{4}}~J.{{g}^{-1}}{}^\circ {{C}^{-1}} D. 1\times {{10}^{4}}~J.{{g}^{-1}}{}^\circ {{C}^{-1}}
B.     3,2\times {{10}^{4}}~J.{{g}^{-1}}{}^\circ {{C}^{-1}} E. 0,5\times {{10}^{4}}~J.{{g}^{-1}}{}^\circ {{C}^{-1}}
C.     2,1\times {{10}^{4}}~J.{{g}^{-1}}{}^\circ {{C}^{-1}}

Penyelesaian

Asas black.

20-kunci

{{Q}_{lepas}}={{Q}_{serap}}

{{m}_{k}}~.{{c}_{k}}~.\Delta T={{m}_{a}}~.{{c}_{a}}~.\Delta T

\left( 0,1 \right)~{{c}_{k}}~\left( 75-50 \right)=0,5~\left( 4200 \right)\left( 50-25 \right)

\left( 0,1 \right)~{{c}_{k}}~\left( 25 \right)=0,5~\left( 4200 \right)\left( 25 \right)

2,5~{{c}_{k}}~=2100

{{c}_{k}}=2,1\times {{10}^{4}}~J.k{{g}^{-1}}.{}^\circ {{C}^{-1}}

jawaban C

 

 

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