Q=cm△t c=4.2X10^3 m=100g=0.1kg △t=35℃-15℃=20℃
Q=4.2X10^3X0.1kgX20℃
=8.2X10^3J
∵Q甲/Q乙=7/1
且Q甲=8.2X10^3J
∴Q乙=8.2X10^3J/7
≈1171.4J
∵Q=cm△t 1171.4=4.2X10^3X0.1kgX △t
△t≈2.9
∴t=15=2.9=17.9℃
Q=cm△t c=4.2X10^3 m=100g=0.1kg △t=35℃-15℃=20℃
Q=4.2X10^3X0.1kgX20℃
=8.2X10^3J
∵Q甲/Q乙=7/1
且Q甲=8.2X10^3J
∴Q乙=8.2X10^3J/7
≈1171.4J
∵Q=cm△t 1171.4=4.2X10^3X0.1kgX △t
△t≈2.9
∴t=15=2.9=17.9℃