A 500 W heater is used to heat 250 mL of water from 20° C to 100° C. What is minimum time in which this can be done?

Question

A 500 W heater is used to heat 250 mL of water from 20° C to 100° C. What is minimum time in which this can be done? (A) 142 s (B) 190 s (C) 167 s (D) 210 s

Tardigrade Admin · Accepted Answer

H=P t=500 t=m s Δ T 500 t=0.25 × 4.184 × 80 × 1000 t=(0.25 × 1000 × 80 × 4.184/500) =167.4 s

Q. A $500 W$ heater is used to heat $250 m L$ of water from $2 0^{\circ} C$ to $10 0^{\circ} C$ . What is minimum time in which this can be done?

142 s

190 s

167 s

210 s

$H = Pt = 500 t = m s Δ T$
$500 t = 0.25 \times 4.184 \times 80 \times 1000$
$t = \frac{0.25 \times 1000 \times 80 \times 4.184}{500}$
$= 167.4 s$

Q. A 500W heater is used to heat 250mL of water from 20∘C to 100∘C. What is minimum time in which this can be done?