A 500W heater is used to heat 0.6kg of water from $25^\circ\mathrm{C}$ to $100^\circ\mathrm{C}$ in $t_2$ seconds. If another 1000W heater is used to h...

Assessment: JAMB UTME - Physics - 1998 Subject: Physics

Question 1 Report

A 500W heater is used to heat 0.6kg of water from $25^\circ\mathrm{C}$ to $100^\circ\mathrm{C}$ in $t_2$ seconds. If another 1000W heater is used to heat 0.2kg of water from $10^\circ\mathrm{C}$ to $100^\circ\mathrm{C}$ in t, seconds, find $\frac{t_1}{t_2}$

50

5

5/4

1/5

Answer Details

Heat energy = Electrical energy

mc $θ$ = power x time

0.6 x c x (100 - 25) = 500 x t1

and, 0.2 x c x (100 - 10)= 100 x t2
$\frac{t_{1}}{t_{2}}$ = 5